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Silicon-mediated alleviation of Cr(VI) toxicity in wheat seedlings as evidenced by chlorophyll florescence, laser induced breakdown spectroscopy and anatomical changes
Abstract
Silicon (Si)-mediated alleviation of Cr(VI) toxicity was examined in wheat seedlings using an
in vivo approach that involves chlorophyll fluorescence, induced breakdown spectroscopy (LIBS) and
anatomical changes. Exposure to Cr(VI) significantly reduced the growth and photosynthetic activities
(chlorophyll fluorescence) in wheat which was accompanied by remarkable accumulation of this
element in tissues. However, addition of Si to the growth medium alleviated the effects of Cr(VI). The
LIBS spectra were used as a fingerprint of the elemental compositions in wheat seedlings, which
showed a reduction in Cr accumulation following Si addition. Nutrient element levels (Ca, Mg, K and
Na) declined in wheat following the addition of Cr (VI), as recorded by LIBS and inductively coupled
plasma atomic emission spectroscopy (ICAP-AES). However, addition of Si along with Cr(VI) increased
the contents of nutrient elements in wheat. LIBS, ICAP-AES and AAS showed a similar distribution
pattern of elements measured in wheat. Anatomical observations of leaf and root revealed that Cr(VI)
affected internal structures while Si played a role in protection from toxic effects. The results showed
the suitability of chlorophyll fluorescence as a parameter and appropriateness of LIBS technique and
anatomical procedures to elucidate Si-mediated alleviation of Cr(VI) toxicity. Furthermore, our results
suggest that the measured parameters and techniques can be used non-invasively for monitoring the
growth of crops under different environmental conditions.
... According to our results, P deficiency decreased chlorophyll fluorescence parameters (F m , F v /F m , F v /F 0 , and F v ) and increased F 0 and NPQ. F v /F 0 measures the activity of PSII (Tripathi et al., 2014), and F 0 estimates the relative antenna pigment level in the PSII complex (Huang et al., 2004). High F 0 and low F m indicate that P deficiency might damage to the photosynthetic apparatus, thereby affecting PSII activity (Tripathi et al., 2014;Pshenichnikova et al., 2019). ...
... F v /F 0 measures the activity of PSII (Tripathi et al., 2014), and F 0 estimates the relative antenna pigment level in the PSII complex (Huang et al., 2004). High F 0 and low F m indicate that P deficiency might damage to the photosynthetic apparatus, thereby affecting PSII activity (Tripathi et al., 2014;Pshenichnikova et al., 2019). Under P deficiency, increased NPQ values reflect light energy absorbed via fluorescence radiation energy in PSII, protecting seedlings from photodynamic damage (Tripathi et al., 2014). ...
... High F 0 and low F m indicate that P deficiency might damage to the photosynthetic apparatus, thereby affecting PSII activity (Tripathi et al., 2014;Pshenichnikova et al., 2019). Under P deficiency, increased NPQ values reflect light energy absorbed via fluorescence radiation energy in PSII, protecting seedlings from photodynamic damage (Tripathi et al., 2014). Although P deficiency reduced F v /F m , the value was still higher than 0.8, which is normally seen in healthy plants (Gao et al., 2001). ...
This study assessed the effect of Bacillus megaterium on seedling growth of Glycyrrhiza uralensis Fisch. under control and phosphorus (P) deficiency conditions. The results showed that P deficiency improved 1) G. uralensis root growth, 2) superoxide dismutase, catalase, and peroxidase activities, 3) inorganic P, starch, and soluble sugar contents in roots, 4) dissipated energy flux per reaction center, trapped energy flux per reaction center, and absorption flux per reaction center, and 5) net photosynthetic rate, stomatal conductance, transpiration rate, maximum fluorescence intensity after dark adaptation, and variable fluorescence. However, P deficiency significantly decreased chlorophyll and carotenoid contents in G. uralensis, but enhanced chlorophyll and carotenoid contents in B. megaterium. Our findings on the regulatory mechanisms of B. megaterium in response to P starvation hold promise for improving the success of G. uralensis cultivation. Keywords: Bacillus megaterium; Glycyrrhiza uralensis Fisch; Phosphorus deficiency; Chlorophyll fluorescence; Antioxidant enzymes superoxide; Non-structural carbohydrate
... One of the major ways silicon helps plants reduce metal toxicity is by reducing the absoprtion and transport of metals, as observed in numerous studies (Ali et al., 2013b;Anwaar et al., 2015;Bokor et al., 2015;Dresler et al., 2015;Farooq et al., 2013;Fleck et al., 2013;Gu et al., 2012;Horst et al., 1999;Hu et al., 2013;Hussain et al., 2015;Keller et al., 2015a;Liang et al., 2005c;Liu et al., 2013;Marmiroli et al., 2014;Naeem et al., 2015;Rizwan et al., 2012;Sanglard et al., 2014;Shen et al., 2014;Shi et al., 2010;Singh et al., 2011;Song et al., 2011;Tripathi et al., 2013Tripathi et al., , 2015Zeng et al., 2011). The reduced plant metal uptake that follows silicon application can be attributed to different mechanisms. ...
... Silicon application to plants under metal toxicity is widely reported to positively affect the photosynthetic machinery and chlorophyll biosynthesis . For example, Si application to heavy-metal-stressed plants increased the carotenoid, chlorophyll a, and chlorophyll b contents in the leaves and improved the gas exchange characteristics (net photosynthetic rate, stomatal conductance, transpiration rate, and WUE) (Ali et al., 2013b;Bharwana et al., 2013;Farooq et al., 2013;Feng et al., 2010;Hu et al., 2013;Hussain et al., 2015;Malčovská et al., 2014;Huerta, 2008, 2010;Rizwan et al., 2012;Sanglard et al., 2014;Shen et al., 2014;Singh et al., 2011;Song et al., 2014;Tripathi et al., 2015;. ...
... Silicon can interact with other elements in plants to reduce the metal toxicity, and plays a significant role in the nutrient absorption of plants that are under heavy metal stress. Silicon application to heavy-metal-stressed plants increased the accumulation and content of macronutrients (Ca, Mg, K, P, etc.) and micronutrients (Fe, Mn, Zn, etc.) (Frantz et al., 2011;Kaya et al., 2009;Keller et al., 2015a;Mehrabanjoubani et al., 2015;Oliva et al., 2011;Rizwan et al., 2012;Tripathi et al., 2015;Wang et al., 2014). Silicon application was observed to lessen the inhibitory effects of heavy metals on the enzymes associated with nitrogen metabolism, including, glutamate synthase (GOGAT), glutamate dehydrogenase (GDH), glutamine synthetase (GS), and nitrogen reductase (NR) in plants (Feng et al., 2010). ...
... Quantification of approved limits of Toxic elements present in any food item is essential. LIBS can be useful to detect toxic elements present in any food item even at a trace level [105]. Since LIBS is capable of identifying and quantifying elements present in any food item, therefore it can be considered as a useful tool in the food sector industry. ...
... Since LIBS is capable of identifying and quantifying elements present in any food item, therefore it can be considered as a useful tool in the food sector industry. Indian researchers performed some experiments for detecting and quantifying the toxic elements present in the foodmaterials [105,106]. Tripathi et al detected and measured the elemental concentration of Si and Cr accumulation in the wheat seeds [105]. Agrawal et al investigated the impurities present in the different colors of ice balls [106]. ...
... Indian researchers performed some experiments for detecting and quantifying the toxic elements present in the foodmaterials [105,106]. Tripathi et al detected and measured the elemental concentration of Si and Cr accumulation in the wheat seeds [105]. Agrawal et al investigated the impurities present in the different colors of ice balls [106]. ...
... It has been established that exogenous supply of SiO 2 NPs displays efficacy to palliate the heavy metals toxicity in major agricultural crops including wheat (T. aestivum) [33,72], maize (Z. mays) [74], common beans (P. ...
... The higher production of antioxidant enzymes by SiO 2 NPs have been documented in P. sativum under Cr stress [73], Z. mays under As stress [74] and T. aestivum under Cd stress [5]. However, the response of SiO 2 NPs to the activities of antioxidant enzymes is complex and can vary depending on the plant species, type of heavy metal, method of metals or SiO 2 NPs supply, and exposure time ( [72,73], 2016; [5,78,79]). Overall, these results indicate that seed priming with SiO 2 NPs plays a protective role in regulating the enzymatic and non-enzymatic regulation in governing antioxidative defense under Cr stress by enhancing their activities or endogenous contents. ...
Plant yield is severely hampered by chromium (Cr) toxicity, affirming the urgent need to develop strategies to suppress its phyto-accumulation. Silicon dioxide nanoparticles (SiO2 NPs) have emerged as a provider of sustainable crop production and resistance to abiotic stress. But, the mechanisms by which seed-primed SiO2 NPs palliate Cr-accumulation and its toxic impacts in Brassica napus L. tissues remains poorly understood. To address this gap, present study examined the protective efficacy of seed priming with SiO2 NPs (400 mg/L) in relieving the Cr (200 µM) phytotoxicity mainly in B. napus seedlings. Results delineated that SiO2 NPs significantly declined the accumulation of Cr (38.7/35.9%), MDA (25.9/29.1%), H2O2 (27.04/36.9%) and O2• (30.02/34.7%) contents in leaves/roots, enhanced the nutrients acquisition, leading to improved photosynthetic performance and better plant growth. SiO2 NPs boosted the plant immunity by upregulating the transcripts of antioxidant (SOD, CAT, APX, GR) or defense-related genes (PAL, CAD, PPO, PAO and MT-1), GSH (assists Cr-vacuolar sequestration), and modifying the subcellular distribution (enhances Cr-proportion in cell wall), thereby confer tolerance to ultrastructural damages under Cr stress. Our first evidence to establish the Cr-detoxification by seed-primed SiO2 NPs in B. napus, indicated the potential of SiO2 NPs as stress-reducing agent for crops grown in Cr-contaminated areas.
... It results in lipid, protein, and nucleic acid degradation in plants. That may lead to seed germination, photosynthesis, or water balance dysfunction [42][43][44]. ...
... This element is highly toxic to wheat plants. It interferes with various metabolic processes and leads to the inhibition of plant growth and development [43]. Our results show that wheat assimilates chromium very effectively. ...
Metalloenzymes play an important role in the regulation of many biological functions. An effective way to prevent deficiencies of essential minerals in human diets is the biofortification of plant materials. The process of enriching crop sprouts under hydroponic conditions is the easiest and cheapest to conduct and control. In this study, the sprouts of the wheat (Triticum aestivum L.) varieties Arkadia and Tonacja underwent biofortification with Fe, Zn, Mg, and Cr solutions in hydroponic media at four concentrations (0, 50, 100, and 200 µg g−1) over four and seven days. Moreover, this study is the first to combine sprout biofortification with UV-C (λ = 254 nm) radiation treatment for seed surface sterilization. The results showed that UV-C radiation was effective in suppressing seed germination contamination by microorganisms. The seed germination energy was slightly affected by UV-C radiation but remained at a high level (79–95%). The influence of this non-chemical sterilization process on seeds was tested in an innovative manner using a scanning electron microscope (SEM) and EXAKT thin-section cutting. The applied sterilization process reduced neither the growth and development of sprouts nor nutrient bioassimilation. In general, wheat sprouts easily accumulate Fe, Zn, Mg, and Cr during the applied growth period. A very strong correlation between the ion concentration in the media and microelement assimilation in the plant tissues (R2 > 0.9) was detected. The results of the quantitative ion assays performed with atomic absorption spectrometry (AAS) using the flame atomization method were correlated with the morphological evaluation of sprouts in order to determine the optimum concentration of individual elements in the hydroponic solution. The best conditions were indicated for 7-day cultivation in 100 µg g−1 of solutions with Fe (218% and 322% better nutrient accumulation in comparison to the control condition) and Zn (19 and 29 times richer in zinc concentration compared to the sprouts without supplementation). The maximum plant product biofortification with magnesium did not exceed 40% in intensity compared to the control sample. The best-developed sprouts were grown in the solution with 50 µg g−1 of Cr. In contrast, the concentration of 200 µg g−1 was clearly toxic to the wheat sprouts.
... In polluted soils, Si can reduce Cr toxicity, which significantly increases the physiological growth of the plants and crop yield (Kharbech et al., 2020). Si-enhanced tolerance against Cr in different species of plants, such as tomato (Alam et al., 2021), mustard (Ashfaque et al., 2017), wheat (Tripathi et al., 2015), and rice (Huda et al., 2017) has also been reported. These studies suggest the protective nature of Si accumulation against Cr toxicity. ...
... However, in the present study, the exogenous application of NaHS and Si, alone or in combination, improved RWC in the leaves of both chickpea plants. Similarly, Si application mitigate the toxic effects of Cr VI by enhancing RWC via reducing metal accumulation (Alam et al., 2021;Yang et al., 2021), which improves plant growth and biomass production and increases the activities of antioxidant enzymes (Tripathi et al., 2015;Huda et al., 2017). ...
Contamination of soils with chromium (Cr) jeopardized agriculture production globally. The current study was planned with the aim to better comprehend how melatonin (Mel) and hydrogen sulfide (H2S) regulate antioxidant defense system, potassium (K) homeostasis, and nitrogen (N) metabolism in tomato seedlings under Cr toxicity. The data reveal that application of 30 μM Mel to the seedlings treated with 25 μM Cr has a positive effect on H2S metabolism that resulted in a considerable increase in H2S. Exogenous Mel improved phytochelatins content and H+-ATPase activity with an associated increase in K content as well. Use of tetraethylammonium chloride (K+-channel blocker) and sodium orthovanadate (H+-ATPase inhibitor) showed that Mel maintained K homeostasis through regulating H+-ATPase activity under Cr toxicity. Supplementation of the stressed seedlings with Mel substantially scavenged excess ROS that maintained ROS homeostasis. Reduced electrolyte leakage and lipid peroxidation were additional signs of Mel's ROS scavenging effects. In addition, Mel also maintained normal functioning of nitrogen (N) metabolism and ascorbate-glutathione (AsA-GSH) system. Improved level of N fulfilled its requirement for various enzymes that have induced resilience during Cr stress. Additionally, the AsA-GSH cycle's proper operation maintained redox equilibrium, which is necessary for the biological system to function normally. Conversely, 1 mM hypotaurine (H2S scavenger) abolished the Mel-effect and again Cr-induced impairment on the above-mentioned parameters was observed even in presence of Mel. Therefore, based on the observed findings, we concluded that Mel needs endogenous H2S to alleviate Cr-induced impairments in tomato seedlings.
... In polluted soils, Si can reduce Cr toxicity, which significantly increases the physiological growth of the plants and crop yield (Kharbech et al., 2020). Si-enhanced tolerance against Cr in different species of plants, such as tomato (Alam et al., 2021), mustard (Ashfaque et al., 2017), wheat (Tripathi et al., 2015), and rice (Huda et al., 2017) has also been reported. These studies suggest the protective nature of Si accumulation against Cr toxicity. ...
... However, in the present study, the exogenous application of NaHS and Si, alone or in combination, improved RWC in the leaves of both chickpea plants. Similarly, Si application mitigate the toxic effects of Cr VI by enhancing RWC via reducing metal accumulation (Alam et al., 2021;Yang et al., 2021), which improves plant growth and biomass production and increases the activities of antioxidant enzymes (Tripathi et al., 2015;Huda et al., 2017). ...
Extensive use of chromium (Cr) in anthropogenic activities leads to Cr toxicity in plants causing serious threat to the environment. Cr toxicity impairs plant growth, development, and metabolism. In the present study, we explored the effect of NaHS [a hydrogen sulfide; (H2S), donor] and silicon (Si), alone or in combination, on two chickpea (Cicer arietinum) varieties (Pusa 2085 and Pusa Green 112), in pot conditions under Cr stress. Cr stress increased accumulation of Cr reduction of the plasma membrane (PM) H⁺-ATPase activity and decreased in photosynthetic pigments, essential minerals, relative water contents (RWC), and enzymatic and non-enzymatic antioxidants in both the varieties. Exogenous application of NaHS and Si on plants exposed to Cr stress mitigated the effect of Cr and enhanced the physiological and biochemical parameters by reducing Cr accumulation and oxidative stress in roots and leaves. The interactive effects of NaHS and Si showed a highly significant and positive correlation with PM H⁺-ATPase activity, photosynthetic pigments, essential minerals, RWC, proline content, and enzymatic antioxidant activities (catalase, peroxidase, ascorbate peroxidase, dehydroascorbate reductase, superoxide dismutase, and monodehydroascorbate reductase). A similar trend was observed for non-enzymatic antioxidant activities (ascorbic acid, glutathione, oxidized glutathione, and dehydroascorbic acid level) in leaves while oxidative damage in roots and leaves showed a negative correlation. Exogenous application of NaHS + Si could enhance Cr stress tolerance in chickpea and field studies are warranted for assessing crop yield under Cr-affected area.
... Among all the heavy metals, Cd was proved to be more persistent to cause oxidative stress and lipid peroxidation using ROS through several oxidation-reduction reactions (Jing et al. 2021). Recently, the synergistic effect of both Se-Si on mitigation of heavy metal toxic effects has been widely reported in several plant species such as rice (Wang and Han 2007;Gao et al. 2018;Huang et al. 2021;Ghouri et al. 2021), wheat (Tripathi et al. 2015;Taha et al. 2021;Zhou et al. 2021b), Pfaffia glomerata (Spreng.) (Pereira et al. 2018) and Chinese cabbage . ...
... (Pereira et al. 2018) and Chinese cabbage . For further understanding of these detrimental effects of heavy metals on physio-biochemical processes of plants, Tripathi et al. (2015) employed in vivo strategy that included chlorophyll fluorescence, laser-induced breakdown spectroscopy (LIBS), and anatomical alterations to investigate the Si-mediated reduction of Cr(VI) toxicity in wheat. In control Cr(VI) accumulation led to reduced plant growth and showed deleterious effects on photosynthetic activities. ...
stress signaling cross-talk. Several studies had provided pieces of evidence for the potential role of Si/ Se in the induction of phytohormonal and anti-oxidant stress signaling mechanisms. Except for greater Se-toxicity at low concentrations when compared to Si, the individual and combined effects of Si/Se in many plants have shown similar induction routes. However, the effectiveness of Si/Se levels in different plant species differs greatly. A vast number of omics studies are currently being conducted in order to determine the exact molecular mechanisms through which Si/ Se activation of the defense response could well be understood. This review aims to uncover the possible molecular convergent points for Si and Se actions as well as their potential cross-talk with stress signaling mechanisms. Abstract The global agriculture system remains vulnerable to several kinds of spatio-temporal abiotic and biotic stressors. At the molecular and physiological levels, the elimination of challenges associated with these stressors in plants has been intensively explored. The plants appear to have evolved with a multitude of physio-biochemical survival strategies, including a central signaling cross-talk channel that allows the plant to arbitrate between active growth and defensive pathways. Furthermore, exogenous administration of micronutrients such as silicon (Si) and selenium (Se) has been shown to improve plant defense responses under stressful situations. These micro-nutrients exhibited a large number of physio-biochemical responses throughout various plant systems and were found associated with pathways of
... The possible mechanism of counteracting the toxic effects of Cd and Cu through the application of Si was correlated with overexpression of metal ion transporter genes, such as OsLsi and OsHMA3 (Kim et al., 2014b). Moreover, Si resulted in declined Al and Cr (Chromium) uptake through roots, stems, and leaves of peanut and rice seedlings, ameliorating toxic effects of these heavy metals Shen et al., 2014;Tripathi et al., 2015). Si in the form of silica gel helps to shuttle the influx transporter (Lsi1) to transport Si rather than arsenic, reducing its toxicity in rice . ...
... Under metal toxicity, it was reported that Si supplementation mediated positive effects on plants through enhancing chlorophyll biosynthesis and, in turn, photosynthetic machinery (Adrees et al., 2015;Imtiaz et al., 2016). The stomatal conductance, net photosynthetic quotient, transpiration ratio increase by enhanced synthesis of carotenoids, chlorophyll a, and b upon administration of Si under heavy metal stress in cotton and wheat plants (Bharwana et al., 2013;Hussain et al., 2015;Tripathi et al., 2015). Si supplementation downregulated the expression of zinc (Zn) transporters under zinc toxicity in maize roots (Bokor et al., 2015). ...
Sustainable agricultural production is critically antagonistic by fluctuating unfavorable environmental conditions. The introduction of mineral elements emerged as the most exciting and magical aspect, apart from the novel intervention of traditional and applied strategies to defend the abiotic stress conditions. The silicon (Si) has ameliorating impacts by regulating diverse functionalities on enhancing the growth and development of crop plants. Si is categorized as a non-essential element since crop plants accumulate less during normal environmental conditions. Studies on the application of Si in plants highlight the beneficial role of Si during extreme stressful conditions through modulation of several metabolites during abiotic stress conditions. Phytohormones are primary plant metabolites positively regulated by Si during abiotic stress conditions. Phytohormones play a pivotal role in crop plants’ broad-spectrum biochemical and physiological aspects during normal and extreme environmental conditions. Frontline phytohormones include auxin, cytokinin, ethylene, gibberellin, salicylic acid, abscisic acid, brassinosteroids, and jasmonic acid. These phytohormones are internally correlated with Si in regulating abiotic stress tolerance mechanisms. This review explores insights into the role of Si in enhancing the phytohormone metabolism and its role in maintaining the physiological and biochemical well-being of crop plants during diverse abiotic stresses. Moreover, in-depth information about Si’s pivotal role in inducing abiotic stress tolerance in crop plants through metabolic and molecular modulations is elaborated. Furthermore, the potential of various high throughput technologies has also been discussed in improving Si-induced multiple stress tolerance. In addition, a special emphasis is engrossed in the role of Si in achieving sustainable agricultural growth and global food security.
... In this study, it was found that the content of photosynthetic pigments decreased in T. vulgaris at all Cr levels. Cr in plants can nega-tively impact their Chl content, carbon fixation, and photosynthetic activity [74], as it causes stomatal closing; damage to the photosynthetic system, the light-gathering complex, and photosystems I and II; and a reduction in Fe, which is essential for Chl content, pigment biosynthesis, and the overall photosynthesis process and apparatus [52,75,76]. The application of CS-NP was shown to enhance the amount of chlorophyll in plants [72], maybe due to the high concentration of amino acids in CS-NPs, which can promote the formation of chloroplasts and chlorophyll [77]. ...
An excessive amount of chromium in soil has detrimental effects on plant processes, and impairs food security, and public health. The application of nanoparticles may be a suitable solution and an innovative strategy by which to reduce plant abiotic stresses and pollution in the agricultural ecosystems. This research focuses on the effects of chitosan nanoparticles (CS-NPs) on thyme (Thymus vulgaris L.) plants grown in Cr-contaminated soil. The effects of CS-NPs as a soil amendment at four concentrations were investigated on plant nutrient uptake, photosynthesis parameters, antioxidant system, and essential oil (EO) content under soil Cr stress. The results show that chromium stress reduced fresh and dry weight of shoots, the uptake of macro-, and micro-elements, chlorophyll and carotenoids. The application of CS-NPs improved the antioxidant enzyme activity, reduced malondialdehyde, and increased the content of nutrients, EOs, photosynthetic pigments, and chlorophyll fluorescence parameters. The intermediate dose of chitosan nanoparticles (0.1% w/v) best valorized the content and yield of thyme EOs under chromium stress. These results are indicative that the application of CS-NPs can represent a supportive approach for plant production in soils contaminated with heavy metals.
... Similarly, Vatehova et al. [79] and Thind et al. [86] found that Si alleviates the negative impact of Cd on pigment content in Brassica juncea L. and wheat respectively. Song et al. [99] reported similar findings in Brassica campestris L. Our results align with the findings of Tripathi et al. [100], who reported enhanced activity of photosystem-II in Indian Raya with Si application. It also increased the rubisco synthesis [84,101]. ...
Heavy metal toxicity poses severe threats to soil and crop productivity. Cadmium (Cd) toxicity disrupts plant metabolism, reducing growth and yield. Si has emerged as a potential element in the context of metal toxicity, playing a crucial role in the compartmentalization and immobilization of metal ions. This study explores the potential of foliar-applied Si to mitigate Cd toxicity in Raya (Brassica juncea L.).
Seedlings underwent Cd toxicity induction using CdCl2 (300 μM) along with control (0 μM) and were subjected to foliar Si application of Na2SiO3 (0 and 500 ppm). The impact on agronomic parameters, photosynthetic pigments, antioxidants (SOD, POD, CAT), and stress markers (H2O2, MDA, proline) was evaluated.
Cd stress reduced agronomic parameters, while Si application, particularly in Super Raya, showed positive effects under stress and non-stress conditions. Photosynthetic pigments decreased in response to Cd stress, although Si had a significant effect. Biochemical attributes such as antioxidants (SOD, POD, and CAT) and stress markers (H2O2, MDA, and proline) increased, with positive effects shown in the Cd+Si treatment.
This study unveils the potential of foliar-applied Si to alleviate Cd-induced toxicity in Raya, offering novel insights into its impact on agronomic and physico-chemical attributes. Si application emerges as an effective strategy to limit Cd uptake in aerial parts of the plant, paving the way for future research in optimizing Si application for enhanced plant resilience to heavy metal stress.
... 427.4, and 428.9 nm (inset of Fig. 5(a 1 ) &(b 1 )) demonstrate the Cr(VI) adsorption onto the pBvBC and nFeO@BvBC surface [42,43]. ...
... Plant biomass recovery increases net photosynthetic rate efficiency. The photosynthetic mechanism of mesophyll tissue has been found to be negatively affected by stress-related changes in chlorophyll fluorescence parameters [53][54][55][56]. Energy absorption by antenna pigments decreases with a reduction in excessive HM-mediated chlorophyll content. ...
World's population is facing serious constrains due to the deposition of heavy metals (HMs) in soil since last decades. Over the years, there has been an increased concern in relation to the HMs impact on the agricultural production. The HMs stress causes severe constrains in yield due to disruption of several physio-biochemical and metabolic activities of the plants. At present, the majority of agricultural practices still rely on conventional methods such as fertilizers and pesticides, but the implementation of more sustainable methods is necessary to meet the nutritional needs of the growing population, which is expected to reach several times higher than the present record. Recently, Si has attracted the attention of researchers for improving the plants growth and development in the presence/absence of HMs stress. In plants, Si nutrition could mitigate the HMs concentration in plants via reducing transpiration rate and improvement in enzyme activities. This review provided an overview on key step towards the toxicity adjustment and morpho-physiological detoxification of HMs by Si. In addition, the emerging role of Si nanoparticles (NPs) to mitigate the HMs toxicity is also highlighted.
... Nearly all major field crops are affected by HM toxicity in terms of grain yield and biomass production. There has been evidence that Si ameliorates manganese (Mn), zinc (Zn), cadmium (Cd), copper (Cu) and aluminum (Al) toxic effects in certain crop species (Pontigo et al., 2015;Tripathi et al., 2015 andDar et al., 2022a). In plants, silicon forms complexes with metals in the rhizosphere that prevent the metal from being absorbed by the plant (Shim et al., 2014). ...
Silicon (Si) as silicic acid, Si(OH)4 offers several benefits to the growth of plants, especially under adverse environmental conditions. Therefore, the present study aimed to assess the role of exogenous Si treatments (0.5 and 1.0 mM) in the tolerance of Fagopyrum esculentum Moench to Al stress applied at two different concentrations (0.2 and 0.4 mM). A set of agrophysiological, biochemical and antioxidant parameters were evaluated during the investigation. The exogenous Si application to Fagopyrum esculentum plants exposed to Al treatments significantly modulated the physiological and antioxidant responses to overcome the Al phytotoxicity and provide beneficial effects. The results indicated that the application of different doses of Al significantly affected the physiological parameters viz., plant growth, tolerance index, biomass accumulation (BA), relative water content (RWC), lipid peroxidation (LP), membrane stability index (MSI) and reduced glutathione (GSH) content. Likewise, aluminum-treated leaves also displayed increased hydrogen peroxide accumulation signifying the extent of the damage in F. esculentum. However, the individual and combined doses of silicon (Si) yielded beneficial effects on the physiological and antioxidant attributes. Multivariate analysis also suggested that individual and combined doses of Si improved physiological (root length (RL), shoot length (SL), root and shoot tolerance index (TI), BA, RWC, MSI and osmolytes) and modulates antioxidant defense enzymes (SOD, APX, GPX, CAT, GR and GST). The study reveals that exogenous Si application acts as a potent stress-modulating agent either via the formation of aluminum-silicate complexes or by improving the efficiency of antioxidant enzymatic activities in Al-contaminated soils.
... Former investigations had revealed that Si could act as a growth regulator in various crops such as maize [70] mustard [71] barley [72] and rice [73] promoting crop growth and yield in stressed environment. According to Singh et al. [74], Cr toxicity reduced seed germination, leading to a decline in crop growth and yield attributes. Si interacted with Cr, reduced its uptake and retention in plant tissues, and subsequently improved the plant growth and yield [57]. Si nutrition improved the plant growth and yield in Cr-stressed environment by improving antioxidant activities [71], photosynthetic efficiency [72], water relations [36], membrane integrity [32], nutrient use efficiency [75], enzymatic activities [57] and hormonal balance [76]. Moreover, Si increased the absorption and transportation of essential nutrients like phosphorous (P) and nitrogen (N) in plants, ultimately promoting plant growth and development under stress conditions [77]. ...
Soil contamination with chromium (Cr) is posing a severe threat to global food security and safety. Conventional strategies being used to combat Cr toxicity are costly, destructive and environmentally problematic. The present study aimed to evaluate silicon (Si) nutrition for ameliorating Cr toxicity in maize (Zea mays L). Experimental plan comprised of four Cr levels, i.e. control (Cr0), 5 mg kg⁻¹ (Cr5), 10 mg kg⁻¹ (Cr10) and 25 mg kg⁻¹ (Cr25), and three Si levels including control (Si0), 15 mg kg⁻¹ (Si15) and 30 mg kg⁻¹ (Si30) with three replications. Maize cultivar Hycorn-339 was used. Each pot was filled with 25 kg soil. Harvesting was done 30, 60 and 120 days after sowing. Cr contamination significantly (p ≤ 0.05) increased Cr concentration in plant tissues with a decrease in plant growth, yield and physiological characteristics, highest reduction with Cr25. The said treatment decreased photosynthetic rate (Pn) by 42%, transpiration rate (Tr) 35%, stomatal conductance (Gs) 31%, relative water content (RWC) 32% and membrane stability index (MSI) 30% compared with Cr0. Si nutrition alleviated the deleterious effects of Cr on maize growth and yield by decreasing its absorption while increasing retention in roots and subsequently restricting its translocation from roots to aerial plant parts. Si30 improved Pn by 16%, Tr 19%, Gs 14%, RWC 12%, MSI 15% and grain yield 19% at Cr25 compared to Cr25 without Si. It was concluded that Si could ameliorate Cr toxicity in maize by restricting its absorption and translocation from roots to aerial plant tissues.
... This exogenous SA increases biomass and tolerance to different stresses (17,36). Nanotechnology is a promising technology that allows materials with sizes less than 100 nanometers (41). It can be used in multiple fields, such as agriculture and industry (29). ...
This experiment was conducted to investigate the effect of different zinc oxide nanoparticle (ZnONPs) concentrations and salicylic acid (SA) on growth characteristics and antioxidant defence from Cucurbita pepo L. callus culture in response to drought stress conditions. The study included two levels of drought induced by sorbitol (0 and 20 g l-1), two concentration of SA (0 and 20 mg l-1), and four concentrations of ZnONPs (0, 100, 200, and 300 ppm). Drought stress by sorbitol showed negative effects on some characteristics of callus culture fresh weight (FW), dry weight (DW), and hydrogen peroxide (H 2 O 2). The exogenous SA showed a positive in most characteristics except for DW, H 2 O 2 and CAT. ZnONPs positively affected all study indicators on tissue culture under drought conditions. The exogenous of both SA and ZnONPs without sorbitol increased significantly in FW and DW. The SA and ZnO NPs with sorbitol increased significantly in biochemical characteristics such as H 2 O 2 , SOD, CAT, proline, and phenolic compounds such as coumaric acid, ferulic acid, caffeic acid, luteolin, and rutin. Cucurbita pepo L. الجفاف من مستويين اسة الدر تضمنت الجفاف. ظروف تحت ا باستعمال استحداثه تم هما لسوربيتول 0 و 20 لتر غم-1 هما السالسيليك حامض من وتركيزين ، 0 و 20 لتر ملغم-1 من اكيز تر أربعة و ، النانوي الزنك جسيمات 0 ، 100 ، 200 ، 300 الوزن مثل الصفات بعض على سلبية ات تأثير الجفاف إجهاد أظهر المليون. في جزء معظم في ا ً إيجابي ً ا دور الساليسيليك بحامض المعاملة أظهرت الهيدروجين. بيروكسيد من اها ومحتو الكالس اع لمزر الجاف الوزن و الطري و الجاف الوزن باستثناء الصفات محتوى hydrogen peroxide وفعالية انزيم catalase الزنك اوكسيد بجسيمات المعاملة أثرت. الساليسليك حامض من بكل المعاملة ادت ز الجفاف. ظروف ظل في الكالس ارع مز على اسة الدر ات مؤشر جميع على إيجابي بشكل النانوي اد ز فيما للكالس. الجاف و الطري الوزن في ملحوظ بشكل السوربيتول بدون النانوي الزنك أوكسيد و أوكسيد و الساليسليك بحامض المعاملة ت محتوى مثل الحيوية الكيميائية الخصائص في ملحوظ بشكل السوربيتول مع النانوي الزنك hydrogen peroxide وفعالية انزيم superoxide dismutase أنزيم وفعالية catalase مثل الفينولية المركبات و البرولين ومحتوى coumaric acid و ferulic acid و caffeic acid و luteolin و rutin. النباتية. نمو منظمات السوربيتول, الثانوي, األيض لألكسدة، المضادة األنظمة المفتاحية: الكلمات
... This exogenous SA increases biomass and tolerance to different stresses (17,36). Nanotechnology is a promising technology that allows materials with sizes less than 100 nanometers (41). It can be used in multiple fields, such as agriculture and industry (29). ...
This experiment was conducted to investigate the effect of different zinc oxide nanoparticle (ZnONPs) concentrations and salicylic acid (SA) on growth characteristics and antioxidant defence from Cucurbita pepo L. callus culture in response to drought stress conditions. The study included two levels of drought induced by sorbitol (0 and 20 g l-1), two concentration of SA (0 and 20 mg l-1), and four concentrations of ZnONPs (0, 100, 200, and 300 ppm). Drought stress by sorbitol showed negative effects on some characteristics of callus culture fresh weight (FW), dry weight (DW), and hydrogen peroxide (H2O2). The exogenous SA showed a positive in most characteristics except for DW, H2O2 and CAT. ZnONPs positively affected all study indicators on tissue culture under drought conditions. The exogenous of both SA and ZnONPs without sorbitol increased significantly in FW and DW. The SA and ZnO NPs with sorbitol increased significantly in biochemical characteristics such as H2O2, SOD, CAT, proline, and phenolic compounds such as coumaric acid, ferulic acid, caffeic acid, luteolin, and rutin.
... Thus, the present result of increased F 0 could be due to a reduction in energy absorption by the antenna pigments. Our observations regarding excess Fe 2+ -mediated reduction in F m, F v /F m , and Φ PSII was also in accordance with similar studies on metal toxicity (Pereira et al., 2013;Tripathi et al., 2015). Decrease in F m and F s values have been reported to be due to a damage to the thylakoid membrane (Belgio et al., 2012;Ralph and Burchett, 1998), which ultimately reduced the maximum quantum yield of photosystem II (F v /F m ) and the photosystem II operating efficiency (Φ PSII ). ...
Iron toxicity originated from excess ferrous ion (Fe2+) availability within plant growth medium remains a potent stress severely limiting rice productivity via alteration of photosynthetic and metabolic processes. Silicon (Si) or potassium (K) individually can enhance plant tolerance to abiotic stresses, including metal toxicity. However, their combined mitigation effects lack proper exploration even though greater alleviation potential could possibly be achieved. The objective of the present study was to evaluate the potential of combined application of Si and K in mitigating Fe2+ toxicity impairments to rice leaf mesophyll tissue. The experiment was laid out in a factorial combination of two Fe2+ levels (0 and 300 mg L−1), two Si levels (0 and 56 mg L−1), and two K levels (0 and 200 mg L−1) following a completely randomized design. Excess Fe2+ impaired leaf mesophyll performance by negatively affecting all tested parameters; however, Si and K significantly reduced those impairments. The integrated application of Si and K resulted in the maximum mitigation effects as high as 23%, 27%, 14%, 40%, 25%, 37%, 24%, 48%, 34%, 28%, 41%, and 15% for total chlorophyll content, maximum quantum yield of photosystem II, membrane stability index, relative cell death, lipid peroxidation, total protein content, free proline content, total polyphenol content, hydrogen peroxide content, total antioxidant activity, net photosynthetic rate, and plant biomass, respectively, compared with the control, with 29% decrease in Fe content and 4.2-fold and 1.7-fold respective increase in Si and K content of rice leaf mesophyll. Silicon or K enhanced photosynthetic performance by boosting antioxidant activity, proline content, and polyphenol content, thereby reducing oxidative damages from Fe2+-generated free radicals like hydrogen peroxide; however, K was comparatively more effective than Si. The combined application of Si and K resulted in significantly better Fe2+ toxicity alleviation response over their sole application for the maximum studied traits. The findings would contribute to the present understanding of Fe2+ toxicity alleviation and help in strategizing crop management practices for sustainable rice production in Fe2+-toxic lowlands.
... It has been found that using engineered nanomaterials can significantly lessen the adverse effects of heavy metals on plants [14,15]. Because of their enormous surface area and high reactivity compared with their bulk form, nanomaterials are helpful for the remediation method and may rapidly penetrate contaminated locations. ...
Heavy metal pollution is one of the major global issues arising from various anthropogenic activities. The natural habitat and human health may be at peril from heavy metal exposure since they are tenacious, bio-accumulative, and non-biodegradable. Therefore, eradicating heavy metals from the soil ecosystem is a crucial responsibility to create a secure, viable, and zero-waste ecosystem. There are numerous techniques for eliminating heavy metals from the environment, but each has its own benefits and drawbacks. When a biological agent is used to degrade pollutants, this process is called bioremediation. Nano-phytoremediation, an emerging bioremediation approach in the field of nanotechnology, uses biosynthesized nanoparticles and plant species for the removal of toxic heavy metals from the environment. It is an efficient, economical, and environmentally friendly technique. The adverse consequences of metal exposure on different plant species have been discovered to be greatly reduced by engineered nanomaterials. Because of their tiny dimensions and huge surface area, nanomaterials have an attraction towards metals and can thus quickly enter the contaminated zone of ecosystems that are metal-challenged. The current review provides an overview of various aspects of nano-phytoremediation for heavy metal remediation.
... This growth reduction is partly due to a decrease in stomatal conductance to prevent cavitation and hydraulic failure, leading to a sharp drop in transpiration and CO 2 assimilation (Johnson et al. 2022). Water restriction can also affect the contents of photosynthetic pigments, soluble and storage carbohydrates, proteins, and amino acids (Patmi et al. 2020), and negatively impact other photosynthetic traits, such as the quantum yield (F v /F 0 ) and the maximum quantum e ciency of photosystem II photochemistry (Tripathi et al. 2015; Li et al. 2020). A decrease in CO 2 assimilation causes an accumulation of NADPH, hindering the transfer of electrons from the photosystem II reaction center (FSII) to NADP + . ...
Background and Aims
Water restriction significantly affects the growth and survival of young plants following transplantation. Although silicon (Si) is not typically considered essential for plants, it can help mitigate abiotic stresses. We hypothesized that Si application in plants, depending on how it is applied, can improve the tolerance to water restriction. The objective was to investigate how applying Si to the leaves and roots of young Eucalyptus urophylla plants can mitigate water restriction effects.
Methods
A greenhouse experiment was conducted with one factor consisting of three Si application methods (via root substrate, foliar spray, and a combination of both) and a control group with no Si; the other factor involved well-watered and water-deficit irrigation regimes, based on 90% and 30% pot capacity, respectively.
Results
Silicon application improved the plant’s tolerance to water restriction by maintaining stable cell turgor and increasing intrinsic water use efficiency. Silicon also helped to reduce stomatal conductance and water losses through transpiration, which prevented a decline in CO2 assimilation and promoted osmoregulation. It also prevented a decrease in chlorophyll content and attenuated oxidative stress, by increasing superoxide dismutase and guaiacol peroxidase activity, which contributed to preventing an increase in lipid peroxidation and electrolyte leakage. The effectiveness of Si supply was higher when applied through the roots or a combination of roots and leaves compared to foliar spray alone.
Conclusion
These findings suggest that Si application can be a useful strategy for improving plant tolerance to water restriction, particularly when applied through the roots.
... 427.4, 428.9 nm (inset of Fig. 4(a 1 ) and (c 1 )) distinctly shows the Cr(VI) adsorption through the pristine and modified GHBC [52,53]. ...
In the present study, the thermal conversion of Arachis hypogaea (groundnut) husk into biochar and its subsequent application in the adsorptive removal of Cr(VI) from an aqueous solution has been studied. The SEM–EDX and LIBS analyses showed that the adsorbent material incorporates both magnesium (Mg) and chromium (Cr) on its surface. The FTIR spectra revealed the involvement of several functional groups in the Cr(VI) adsorption, including –OH, Mg–O–Mg, –CH, –NH, and –COO. Specific surface area (SSA) is determined using BET (Brunauer–Emmett–Teller) analysis and the SSA of adsorbent material was 35.83 m² g⁻¹. Data from batch adsorption experiments demonstrated that magnesium-supported biochar increased the binding capacity of the adsorbent to the Cr(VI) ions. Adsorption experiment data at equilibrium conditions showed that the Langmuir model provided a best suited to the nMgO@GHBC than the Freundlich and Temkin models with a maximum adsorption capacity of 93.86 mg g⁻¹. The kinetic-second-order model with the highest R² value of 0.993 and the lowest values for root mean square error and chi-square (χ²) can reasonably explain the hexavalent chromium adsorption data. This study suggested that the mechanism of Cr(VI) adsorption onto both adsorbents might be chemisorption or ion exchange processes as adsorption data effectively fitted the PSO model. The outcomes of thermodynamic parameters like ΔG° indicated that Cr(VI) adsorption on pGHBC and nMgO@GHBC was spontaneous. Fixed-bed-column studies were conducted at different experimental conditions, such as inlet flow rate and bed height. The outcomes of the experimental data showed that the adsorption capacity of adsorbent for Cr(VI) adsorption in a fixed bed continuous flow was 50 mg g⁻¹. The adsorbent was recycled ten times using NaOH, HNO3, H2SO4, and EDTA. The continuous adsorption and desorption of Cr ions for up to 10 cycles showed the reusability of spent biochar.
Graphical Abstract
... Moreover, it affects water relations in drought-stressed plants, as it induces the formation of a silica cuticle double layer under the leaf epidermis which reduces water losses through cuticular transpiration [120]. Recent research has demonstrated that Si is associated with the regulation of antioxidant enzymes [121], increase in synthesis of endogenous antioxidants leading to mitigation of oxidative stress [50], maintenance of net photosynthesis through the stabilization of chloroplast structures, PSII integrity, and increased pigment concentration [122,123] when plants are subjected to heavy metal treatment [116]. Something else worth noting is that since the ceramic powder had previously been fermented with photosynthetic bacteria, it would also bring products of their metabolism. ...
The issue of high concentration of salt in soil is not restricted to coastal areas, but also expands to cultivated lands, complicating, or even intercepting, the growth of plants. The objective of this paper is to study the effect of zeolite, compost and effective microorganisms (EM), seaweed extract, and ceramic powder on MM106 apple (Malus domestica Borkh.) plants in normal and saline conditions. More specifically, the weight of the dry matter of the plants, physiological parameters, proline, carbohydrate, carotenoid, phenolic, and flavonoid concentrations in leaf tissues and antioxidant capacity were determined. At the end of the experiment, it was ascertained that the plants of the treatments which included zeolite or EM exhibited the highest dry matter weight of the leaves in normal (5.07 g and 4.68 g, respectively) and saline conditions (4.14 g and 3.02 g, respectively), while the leaf dry weight in the control treatment was 4.37 g in the absence and 2.34 g in the presence of NaCl. Furthermore, these treatments resulted in significantly higher proline concentration in plant leaves under salinity with values of 5.63 in the EM treatment, 2.44 in the zeolite treatment, and 0.75 μmol/g of leaf fresh weight in the control. At the same time, the application of ceramic powder in combination with effective microorganisms led to the highest rate of photosynthesis in salinity conditions (12.8 μmol CO2/m2s), while the seaweed extract spraying was associated with low stomatal conductance in all treatments (0.09–0.13 mol H2O/m2s). Overall, the application of effective microorganisms appeared to associate more with plant vigor in both normal and salinity conditions. In this context, the implementation of EM could improve the growth of potted plants, but it could also be used in orchards before and after their establishment.
... (Adrees et al. 2015b;Emamverdian et al. 2020). Si markedly enhances the tolerance of plants to HMs by reducing the uptake of HMs such as Pb (Bharwana et al. 2013;Emamverdian et al. 2020), zinc (Zn) (Kaya et al. 2009), cadmium (Cd) Kaya et al. 2020;Thind et al. 2020), chromium (Cr) (Tripathi et al. 2015), arsenic (As) (Sil et al. 2019), and manganese (Mn) (Shi et al. 2005) to promote plant growth. The presence of metals in organisms, especially those that are able to participate in the Fenton reaction, often accelerates the generation of excess reactive oxygen species (ROS) (Adrees et al. 2015b;Ahmad et al. 2019;Kohli et al. 2019;Bhat et al. 2019), which attack the cell membrane and cause lipid peroxidation, resulting in malondialdehyde (MDA) accumulation (Zhu and Gong 2014;Luyckx et al. 2021). ...
Herein, 7,308 relevant documents on biochar application for the remediation of heavy metal (HM)-contaminated soil (BARHMCS) from 1991 to 2020 were extracted from the Web of Science Core Collection and subjected to bibliometric and knowledge mapping analyses to provide a global perspective. The results showed that (1) the number of publications increased over time and could be divided into two subperiods, i.e., the slow growth period (SGP) and rapid growth period (RGP), according to whether the annual publication number was ≥300. (2) A total of 126 countries, 741 institutions, and 1,021 scholars have contributed to this field. (3) These studies are mainly published in Science of the Total Environment, Chemosphere, etc., and are mainly based on the categories of environmental science, soil science, and environmental engineering. (4) The top five keyword clusters for the SGP were biochar, biochar, sorption, charcoal, and HMs, and those for the RGP were adsorption, black carbon, nitrous oxide, cadmium, and pyrolysis. (5) The main knowledge domains and the most cited references during the SGP and RGP were discussed. (6) Future directions are related to biochar application for plant remediation, the mitigation of climate change through increased carbon sequestration, biochar modification, and biochar for HMs and multiple organic pollutants.
... Sustainable crop productivity can be enhanced by the accumulation of Si as it protects plants from various abiotic stresses such as metals, temperature, salinity, and drought [22,25,26]. Silicon also regulates various molecular aspects of the plants under both normal and stressed conditions [22,27,28]. Several researchers have found that different metal and metalloid stresses such as lead (Pb), As, cadmium (Cd), mercury (Hg), Al, manganese (Mn), zinc (Zn), copper (Cu), or antimony (Sb) can be mitigated by the exogenous application of Si in various plant cultivars [29][30][31]. ...
Arsenic (As) contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world. Therefore, the present study was designed to investigate the individual as well as the combined effects of exogenous silicon (Si) and sodium nitroprusside (SNP), a nitric oxide (NO) donor, on plant growth, metabolites, and antioxidant defense systems of radish (Raphanus sativus L.) plants under three different concentrations of As stress, i.e., 0.3, 0.5, and 0.7 mM in a pot experiment. The results showed that As stress reduced the growth parameters of radish plants by increasing the level of oxidative stress markers, i.e., malondialdehyde and hydrogen peroxide. However, foliar application of Si (2 mM) and pretreatment with SNP (100 µM) alone as well as in combination with Si improved the plant growth parameters, i.e., root length, fresh and dry weight of plants under As stress. Furthermore, As stress also reduced protein, and metabolites contents (flavonoids, phenolic and anthocyanin). Activities of antioxidative enzymes such as catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD), and polyphenol oxidase (PPO), as well as the content of non-enzymatic antioxidants (glutathione and ascorbic acid) decreased under As stress. In most of the parameters in radish, As III concentration showed maximum reduction, as compared to As I and II concentrations. However, the individual and combined application of Si and NO significantly alleviated the As-mediated oxidative stress in radish plants by increasing the protein, and metabolites content. Enhancement in the activities of CAT, APX, POD and PPO enzymes were recorded. Contents of glutathione and ascorbic acid were also enhanced in response to co-application of Si and NO under As stress. Results obtained were more pronounced when Si and NO were applied in combination under As stress, as compared to their individual application. In short, the current study highlights that Si and NO synergistically regulate plant growth through lowering the As-mediated oxidative stress by upregulating the metabolites content, activity of antioxidative enzymes and non-enzymatic antioxidants in radish plants.
... (Adrees et al. 2015b;Emamverdian et al. 2020). Si markedly enhances the tolerance of plants to HMs by reducing the uptake of HMs such as Pb (Bharwana et al. 2013;Emamverdian et al. 2020), zinc (Zn) (Kaya et al. 2009), cadmium (Cd) Kaya et al. 2020;Thind et al. 2020), chromium (Cr) (Tripathi et al. 2015), arsenic (As) (Sil et al. 2019), and manganese (Mn) (Shi et al. 2005) to promote plant growth. The presence of metals in organisms, especially those that are able to participate in the Fenton reaction, often accelerates the generation of excess reactive oxygen species (ROS) (Adrees et al. 2015b;Ahmad et al. 2019;Kohli et al. 2019;Bhat et al. 2019), which attack the cell membrane and cause lipid peroxidation, resulting in malondialdehyde (MDA) accumulation (Zhu and Gong 2014;Luyckx et al. 2021). ...
A hydroponic method was conducted to test whether Spathiphyllum kochii is tolerant to multiple HMs as well as to evaluate whether sodium silicate promotes plant growth and alleviates HM stress mainly by assessing biomass, HM accumulation characteristics and antioxidant enzyme activities (AEAs). Three soil extractions from an uncontaminated soil, a comparable lightly HM-contaminated soil (EnSE), and a comparable heavily HM-contaminated soil (ExSE) with or without 1 mM sodium silicate supplementation were used. S. kochii showed no obvious symptoms when cultured in EnSE and ExSE, indicating that it was a multi-HM-tolerant species. The biomass and photosynthesis followed the order: UnSE > EnSE > ExSE, but the opposite order was found for HM concentration, AEAs, and malondialdehyde content. Silicate had no effects on the growth and HM bioaccumulation characteristics of S. kochii cultured in UnSE but exhibited a novel role in decreasing HM uptake by 13.61-41.51% in EnSE and ExSE, respectively, corresponding upregulated AEAs, and reduced malondialdehyde contents, resulting in increased biomass and alleviating HM stress. The activities of peroxidase and superoxide dismutase were upregulated by an increase in soil extraction HM concentration and further upregulated by silicate supplementation, indicating that they were important mechanisms alleviating HM stress in S. kochii.
... Plants are normallyexposed to severalecological stresses and have produced particular response mechanisms (Ramegowda and Senthil-Kumarb, 2015). Within the recent ten years, a need for grasping the molecular mechanisms has arisen which has application on biotic and abiotic stresstolerance (Tripathi et al., 2015;Tripathi et al., 2016;Pontigo et al., 2017;Singh et al., 2017;Tripathi et al., 2017). ...
PGPR are those bacteria occurring as natural colonizers of soil which had gained worldwide importance in the field of agricultural enhancement. They had been observed in essential requirements to increase the productivity of soil by regaining fertility. Advancement of life in all systems has been nowadays not only reliant on farming butdietsafetyplay a chief role in satisfying the growing population basic needs.The viability of soilenvironmentserve as a source of a non-stopmanifestation of soil bacteria. There are even other aspects of soil GSJ: Volume 8, Issue 5, May 2020 ISSN 2320-9186 359 GSJ© 2020 www.globalscientificjournal.com which play conservatory role in soil fertility; including of plants in synergistic co-evolution, soil microbes and bio-mineralization. The growth of population globally has put pressure on farming thus demanding chemical fertilizer's high yield. Meanwhile with the application of peats and insect killer in the farming area have ruined the soil worth and richness, resulting incontraction of farmingacreage havingproductive soil, therefore the consideration of scientists and researchers has moved towards harmless and fruitful sources of farmingcarry out. (PGPR) Plant growth promoting rhizobacteria has been effective by co-evolution between plants and microbes. Bacteriologicalrevival had been attained byplant growth promoters activatedby direct and indirect tacticssuch as disease resistance, rhizoremediation, bio-fertilization, invigorating root growth, etc. The sort of unpredictability existed in the working of PGPR because of several ecological influences that effect their progression and propagation in plants. Due to existent limitations playing its role in agronomy PGPR applications were not improving. Theserestrictions could be overcome byusage of presentmethodologies and practices such asMicro-encapsulation and Nano-encapsulation.Theintroduction of new coming and modern research techniques are supporting their applications with the help of fields such as chemical engineering, biotechnology, agro biotechnology, nanotechnology, and material science by bringing together different environmental and practicalliving approaches to arrange new designs and prospects of hugeprospective.
... Excess Cr is likely to reduce crop growth, damage roots, and lessen yields, ROS produced by Cr can cause serious crop oxidation. Cr 6+ affected internal structures and reduce nutrient elements (Tripathi et al., 2015b). Cr 6+ accumulation rates significantly lessened after Si was added, it may because that Si played a role in protection to plants from toxic effects. ...
Plant growth, development, and productivity are hindered by a wide range of environmental stresses, posing significant challenges. In the pursuit of sustainable agriculture, nanotechnology has emerged as a leading approach to address these constraints, surpassing conventional methods. Silicon nanoparticles (SiNP) have garnered considerable attention due to their unique properties, including solubility, substantial specific surface area, compatibility with living organisms, and facilitation of essential biological interactions. These inherent traits endow SiNP with immense potential to exert prophylactic effects in both biotic and abiotic stress conditions. However, a major obstacle lies in the scarcity of plant-accessible monosilicic acid, the primary form of silicon in most cultivated soils, presenting a significant challenge to realizing the benefits of SiNP. Compounding this issue, conventional silicate fertilizers (bulk-Si) demonstrate limited effectiveness. Nevertheless, recent advancements in nanotechnology have paved the way for enhancing crop yields through SiNP application. Recent studies have demonstrated the effectiveness of SiNP in alleviating both biotic and abiotic stresses in plants. These nanoparticles have shown efficacy in mitigating the detrimental impacts of various abiotic stresses such as drought, salinity, and heavy metal stress. Moreover, SiNP enhance plant vigor and bolster resistance to external stressors. Initially, the protective function of SiNP was attributed to their role as a physical barrier, reinforcing the plant cell wall and preventing penetration by fungal hyphae. However, further research has unveiled the intricate effects of SiNP on plants, involving communication within the cell interior and influencing plant metabolism. Consequently, there is an urgent need for in-depth investigation to explore the potential applications of SiNP in agriculture. This article aims to provide a comprehensive and meticulous overview of SiNP synthesis, practical applications, and their role in enhancing plant growth while mitigating challenges from living organisms and environmental factors. Furthermore, it discusses the advantages of SiNP over traditional bulk-Si fertilizers in agriculture, their effectiveness across diverse plant types, and safety considerations. Additionally, the article highlights gaps in current knowledge regarding SiNP interactions with plants, which can guide future research in this rapidly advancing field. By focusing on research related to SiNP, the full potential of their role in agriculture can be realized, leading to innovative and sustainable approaches for enhancing crops and boosting resilience to stress.
Molecular and Physiological Insights into Plant Stress Tolerance and Applications in Agriculture Part 2 is an edited volume that presents research on plant stress responses at both molecular and physiological levels. This volume builds on the previous volume to provide additional knowledge in studies on the subject.
Key Features
- Explains aspects of plant genetics central to research such as the role of cytosine methylation and demethylation in plant stress responses, and the importance of epigenetic genetics in regulating plant stress responses.
- Explores how Late Embryogenesis Abundant proteins affect plant cellular stress tolerance with an emphasis on their molecular mechanisms and potential implications.
- Focuses on beneficial microorganisms including rhizobacteria, endophytes, and mycorrhizal fungi, which are expected to be alternative fertilizers with the advantages of being cost-effective, toxin-free, and eco-friendly.
- Highlights the potential use of endophytic bacteria for protecting crops against pathogens
- Presents an in-depth analysis of the molecular level to understand the impact of ATP-binding cassette transporters on plant defense mechanisms with a discussion of the potential anti-pathogenic agents based on terpenes and terpenoids.
The content of the book is aimed at addressing UN SDG goals 2, 12, and 15 to achieve zero hunger and responsible consumption and production, and to sustainable use of terrestrial ecosystems, respectively.
This comprehensive resource is suitable for researchers, students, teachers, agriculturists, and readers in plant science, and allied disciplines.
Heavy metal pollution has become a grave environmental problem drawing worldwide attention. Reclamation of polluted land using innovative and ecofriendly way is crucial to restore soil fertility. During the past two decades, various approaches of bio-/phytoremediation are gaining their acceptance to remediate contaminated soil. Recently, the use of reactive nanomaterials for phytoremediation or ‘nano-phytoremediation’ is becoming popular, claiming to improve the phyto-availability of heavy metals and reduce their toxicity through transformation or detoxification. Nanomaterials exhibit distinct properties concerning size, shape, reactivity, and ratio of surface area to volume rendering their potential for a range of applications including remediation of polluted soil environments with heavy metals, chlorinated organic solvents, organochlorine pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. Further, the combination of plants and associated microbes such as rhizospheric bacteria or arbuscular mycorrhizal fungi has the potential to significantly improve the nano-phytoremediation of heavy metal contaminated soil. This review focuses on recent developments on nano-phytoremediation, plant root associated microbes, and their interaction for developing an integrated and efficient nano-phytoremediation strategy for improved soil remediation in general and for soil contaminated with heavy metal. The application of nanomaterials combined with phytoremediation was discussed.
The gasification filter cake (GFC) has great application potential for improving the characteristics of seedling substrates due to its nutrient richness and excellent water retention capacity. However, GFCs leach heavy metals easily and thus pose certain ecological risks. Sodium silicate can enhance plant resistance to heavy metal toxicity by fixing heavy metals. This study investigated the impact of sodium silicate on cucumber plant growth, the chemical characterization of the substrate, and the distribution and transfer of heavy metals. Sodium silicate was added to the seedling substrate mix at mass rates of 0 g/kg−1 (GFC0), 2 g/kg−1 (GFC2), 4 g/kg−1 (GFC4), and 8 g/kg−1 (GFC8). The seedling substrate was composed of a commercial matrix, caragana compost, and GFC (m:m 7:7:2). The GFC increased the content of total phosphorus (P), available phosphorus (P), and available potassium (K) in the substrate by 31.58%, 16.58%, and 80.10%, respectively. Conversely, the GFC decreased the plant height by 12.3%. Adding sodium silicate to the GFC increased the chlorophyll content of the plants, fixed heavy metals in the substrate, and promoted nutrient absorption and utilization by the plants. Compared with GFC0 without sodium silicate, adding sodium silicate at a mass rate of 2 g/kg−1 (GFC2) reduced the chromium, lead, and cadmium contents by 51.13%, 26.37%, and 90.04%, respectively, which effectively alleviated heavy metal stress and was more conducive to plant growth.
Prispevek na podlagi širokega pregleda literature obravnava vlogo silicija pri rastlinah, od same pojavnosti silicija v tleh preko mehanizmov privzema in prenosa, do nalaganja in deleža silicija v rastlinah. Članek nadalje zajema evolucijski vidik pojavnosti silicija pri rastlinah ter izpostavlja njegove ključne vloge pri uspevanju rastlin in blaženju negativnih učinkov številnih stresnih dejavnikov ter njegovo uporabnost v kmetijstvu.
Heavy metals deliberately released into the environment can cause serious environmental damage, as they tend to accumulate in cultivated soils, affecting crops, which start to absorb them through their roots, and when absorbed in high amounts they can become toxic and promote negative effects for plants, soil, man and animals. The absorption of heavy metals by plants, even at low concentrations, can promote negative effects on growth, and at high concentrations, these effects can go beyond the reduction of crop development, causing serious physiological damage that can lead to large losses in agricultural production. Given this scenario of heavy metal stress, numerous studies have shown that silicon (Si) is considered beneficial to plants because it mitigates the deleterious effects of stresses caused by the toxicity of metals and metalloids in plants, by improving photosynthetic activity, increasing enzyme activity antioxidants, which help to reduce oxidative stress, in addition to increasing the absorption of macro and micronutrients. In this chapter, we aim to report the main aspects of the use of Si as a mitigator of toxicity by heavy metals in plants, emphasizing aspects ranging from absorption and accumulation to defense mechanisms related to the use of silicon.KeywordsHeavy metalSiCadmiumToxicity
Despite the growing concerns about arsenic (As) toxicity, information on wheat adaptability in such an aggravating environment is limited. Thus, the present investigation based on an iono-metabolomic approach is aimed to decipher the response of wheat genotypes towards As toxicity. Wheat genotypes procured from natural conditions were characterized as high As-contaminated (Shri ram-303 and HD-2967) and low As-contaminated (Malviya-234 and DBW-17) based on ICP-MS As accumulation analysis. Reduced chlorophyll fluorescence attributes, grain yield and quality traits, and low grain nutrient status were accompanied by remarkable grain As accumulation in high As-contaminated genotypes, thus imposing a higher potential cancer risk and hazard quotient. Contrarily, in low As-contaminated genotypes, the richness of Zn, N, Fe, Mn, Na, K, Mg, and Ca could probably have supported less grain As accumulation, imparting better agronomic and grain quality traits. Additionally, from metabolomic analysis (LC-MS/MS and UHPLC), abundances of alanine, aspartate, glutamate, quercetin, isoliquiritigenin, trans-ferrulic, cinnamic, caffeic, and syringic bestow Malviya-234 as the best edible wheat genotype. Further, the multivariate statistical analysis (HCA, PCA, and PLS-DA) revealed certain other key metabolites (rutin, nobletin, myricetin, catechin, and naringenin) based genotypic discrimination that imparts strength to genotypes for better adaptation in harsh conditions. Out of the 5 metabolic pathways ascertained through topological analysis, the two main pathways vital for plant's metabolic adjustments in an As-induced environment were: 1. The alanine, aspartate and glutamate metabolism pathway, and 2. The flavonoid biosynthesis pathway. This is also evident from network analysis, which stipulates amino acid metabolism as a prominent As regulatory factor closely associated with flavonoids and phenolics. Therefore, the present findings are useful for wheat breeding programs to develop As adaptive genotypes that are beneficial for crop improvement and human health.
The root is an important organ affecting cadmium accumulation in grains, but there is no comprehensive research involving rice root phenotype under cadmium stress yet. To assess the effect of cadmium on root phenotypes, this paper investigated the response mechanism of phenotypic information including cadmium accumulation, adversity physiology, morphological parameters, and microstructure characteristics, and explored rapid detection methods of cadmium accumulation and adversity physiology. We found that cadmium had the effect of "low-promotion and high-inhibition" on root phenotypes. In addition, the rapid detection of cadmium (Cd), soluble protein (SP), and malondialdehyde (MDA) were achieved based on spectroscopic technology and chemometrics, where the optimal prediction model was least squares support vector machine (LS-SVM) based on the full spectrum (Rp=0.9958) for Cd, competitive adaptive reweighted sampling-extreme learning machine (CARS-ELM) (Rp=0.9161) for SP and CARS-ELM (Rp=0.9021) for MDA, all with Rp higher than 0.9. Surprisingly, it took only about 3 min, which was more than 90% reduction in detection time compared with laboratory analysis, demonstrating the excellent ability of spectroscopy for root phenotype detection. These results reveal response mechanism to heavy metal and provide rapid detection method for phenotypic information, which can substantially contribute to crop heavy metal control and food safety supervision.
Cadmium is an important soil pollutant and poses serious challenges to crop production due to its significant toxicity to crop plants. However, crop plants possess several homeostatic cellular processes or mechanisms that can regulate or detoxify high Cd concentrations to mitigate their toxicity to cells and tissues. These cellular processes can be enhanced or promoted by the exogenous application of nanoparticles due to their ability to cross cellular barriers because of their specific physical and chemical features. Therefore, this chapter presents an overview of recent advances regarding the use of nanoparticles in the alleviation of Cd toxicity in crop plants. Additionally, the mechanisms of alleviation of Cd toxicity by exogenously-applied nanoparticles were explored to better understand the regulation of Cd toxicity in crop plants in the presence of nanoparticles.
نفذت تجربة في أصص لدراسة تأثير خلط المواد النانوية بتربة زراعة نباتات الشعير (Hordeum vulgare) النامية تحت مستويات مختلفة من الرطوبة على بعض مؤشرات النمو والحاصل ومكوناته. طبقت التجربة بترتيب الألواح المنشقة مرة واحدة وبتصميم القوالب الكاملة المعشاة RCBD)) Randomized Completely Block Design بثلاثة مكررات، إذ تضمن العامل الرئيس (Whole or Main plots) معاملات الري وهي (الري كل 3 و 6 و 9 و 12 و 15 يوم) وأشتمل العامل الثانوي (Sub-plots) على نسب خلط المواد النانوية مع تربة الزراعة وهي (تربة بدون معاملة (معاملة المقارنة) وترب مخلوطة بنسب 1% و 2% و 3% و 4% و 5%) وبثلاث مكررات. وقد تم التوصل إلى النتائج الاتية: أدى اتساع المدة بين الريات مرة كل 15 يوماً إلى انخفاض اغلب الصفات التي تم تقديرها، وتفوقت معاملة الري كل 12 يوم في صفات عدد الاشطاء والأوراق (10.54 شطأ/ نبات و 10.47ورقة/ نبات) وعدد السنابل (10.33 سنبلة/ نبات) ووزن الحبوب (4.06 غم/ نبات) ووزن المادة الجافة الكلية (8.60 غم/ نبات) ودليل الحصاد (47.20%). أدى خلط تربة الزراعة بأي نسبة من المواد النانوية إلى تحسين أغلب مؤشرات النمو وحاصل الحبوب ومكوناته، وتفوقت معاملة الخلط بنسبة 4% في صفات طول النبات ووزن الحبوب والمادة الجافة الكلية للنبات ودليل الحصاد، أما الخلط بنسبة 5% فقد تفوق في صفات طول المجموع الجذري وعدد أشطاء النبات وعدد أوراقه والوزن الجاف للمجموع الخضري وعدد سنابل النبات. أظهرت معاملات تداخل معاملات الري مع نسب خلط التربة بالمواد النانوية تأثيراً معنوياً في اغلب الصفات التي تم تقديرها، ولوحظ إن أغلب الصفات ازدادت قيم متوسطاتها عند تداخل معاملات الري مع النسب المتزايدة من المواد النانوية المخلوطة مع تربة الزراعة، أكثر من تداخل معاملات الري مع عدم خلط التربة مع المواد النانوية. كانت قيمة معامل الانحدار البسيط موجبة لأغلب الصفات، مما أشار إلى تزايد القيم المتوقعة لتلك الصفات مع تزايد نسبة خلط المواد النانوية. وهذا ما يشير إلى ان خلط ترب الزراعة ولاسيما الخفيفة منها بالمواد النانوية قد يساهم بفعالية في التخفيف من تاثيرات النقص الرطوبي على إنتاجية النبات وتوفير في كميات مياه الري . الكلمات المفتاحية : المواد النانوية ، السيليكون (SiO2) ، الأجهاد المائي
The prevailing environmental conditions control the growth and development of plant in one way or the other throughout the world. Abiotic stresses, i.e., drought, heavy metals, salinity, heat and cold and other environmental extremes negatively influence survival of plants and reduce the productivity of crops. The world’s most popular grain, wheat (Triticum aestivum L.), is highly susceptible to abiotic stress, which is the major reason for yield losses in the crop. Silicon (Si) is the second most abundant element and gaining popularity for its multilateral role in providing significant advantages for growth and yield of crop plants. It is a non-essential nutrient, but it has been shown to have beneficial effects on the growth and development of several plant species. Si substantially reduces the most abiotic stresses and it is non-polluting, non-detrimental and non-harmful to plants even when used in large quantities. Exogenous Si application prevents the detrimental effect of drought, heat and cold stress by increasing cuticle and epidermal layer thickening from silica deposited. Si creates an apoplastic barrier in the endodermis closer to the root apex to prevent the uptake and mobility of heavy metals. Under adverse conditions, Si increases nutrient uptake and restores wheat growth and production. The review clearly reveals the importance of Si nutrition in imparting abiotic stress tolerance and the need for its application in the wheat crop. Plant producers can benefit from Si fertilizers both economically and environmentally.
Laser-Induced Breakdown Spectroscopy (LIBS) has established its position as a method for the analysis of biological samples. We aim to introduce the benefits of LIBS for the qualitative elemental imaging of tissues. The state-of-the-art instrumentation enables elemental imaging of sample surfaces with a high resolution (down to micro-scale) on a large scale (up to a whole-slide image), i.e., megapixel imaging of the distribution of investigated elements. The implementation of this promising tool to the analytical pipeline in various fields (from developmental biology to clinical research) is discussed. The typical interpretation of LIBS results through basic spectroscopic algorithms and machine learning is dissected. The chapter reviews recent advances of LIBS namely in soft and hard tissue analyses when the detection of endogenous and exogenous elements (major and trace metals) is concerned. The comparison to other elemental imaging methods (namely Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is given. Finally, future perspectives and development of LIBS bioimaging is suggested.
Minerals in rice leaves is a crucial indicator of plant health, and their concentrations can be used to guide plant management. It is important to predict mineral content in contaminated rice rapidly. In this study, Laser-induced breakdown spectroscopy (LIBS) was applied to quantify minerals (Ca, Cu, Fe, K, Mg, Mn, and Na) in rice leaves under chromium (Cr) stress. Two feature extraction methods, including principal component analysis (PCA) and extreme gradient boosting (XGBoost), were compared to identify important variables that related to mineral concentrations. Results showed that partial least square regression (PLSR) achieved good performance in Ca, Fe Mg, K, Mn and Na, with correlation coefficient of 0.9782, 0.8712, 0.8933, 0.9206, 0.9856, and 0.9865, root mean square error of 219.25, 14.78, 1192.47, 385.12, 9.56, and 124.32 mg/kg, respectively. In addition, the correlation between different spectral lines were further analyzed. Cr exhibited a positive correlation with Ca, Mg and Na, and a negative correlation with Mn, Cu and K. The proposed method provides a high-accuracy and fast approach for minerals prediction in rice leaves under Cr stress, which is important for environmental protection and food safety.
Anthropogenic activities and/or natural processes have aggravated heavy metal pollution worldwide. Heavy metal uptake beyond the permissible threshold inflicts a plethora of physiological and metabolic anomalies that affect crop quality and productivity. Unprecedented biomagnification and bioaccumulation of arsenic is an environmental disaster predominating in the countries of South East Asia where arsenic‐contaminated groundwater is extensively utilized for drinking and irrigation purposes. Arsenic pollution limits crop productivity by interfering with critical physiological and biochemical aspects of plant metabolism. The toxicological concerns of the metalloid are a menace to food safety as well as health and claim urgent solutions. Immediate strategies to curb the emerging issues would, therefore, be an effective approach to mitigate the hazards of arsenic poisoning and quick, inexpensive as well as environment‐friendly techniques seem to be the alternative. Exogenous supplies of proline, nitric oxide (NO), silicate, phosphate, selenate, and phytohormones, viz. auxins, gibberellins, cytokinins, brassinosteroids, and salicylic acid (SA) have been accounted to shield crop plants against heavy metal stress. These chemicals principally lower the uptake of arsenic and modulate the levels of enzymatic and nonenzymatic antioxidants to augment the antioxidative defense. Administration of these chemicals independently with arsenate has the ability to curtail the arsenic‐persuaded consequences and may be employed to expunge arsenate toxicity with encouraging implications in agrobiological systems. Despite numerous published reports on the morphophysiological effects of these substances in plants, comprehensive research in this arena would widen our awareness to enhance agricultural yields in arsenic‐contaminated soils and develop cost‐effective as well as environmentally benign agriculture.
Gladiolus is an important cut flower crop which has a significant contribution in Pakistan's economy by earning foreign currency. Drought is one of the main cause of decreasing ornamental crop production in most parts of the world while silicon (Si) is considered an element which can protect plants from adverse water shortage conditions. Present pot experiment was carried out to investigate the impact of drought stress and its mitigation by Si on the vegetative and reproductive attributes of Gladiolus grandifloras cv. Advance Red. Three different concentrations of Si (0.5, 1.0 and 1.5mmol/L) were selected to mediate drought stress at 100%, 75% and 50% field capacity (FC) levels. Pots were arranged according to completely randomize design (CRD) with two factor factorial arrangement which were replicated thrice. Results revealed that vegetative characteristics like plant height (cm), leaf area (cm 2), root length (cm), spike length (cm), spike diameter (mm), stem fresh and dry weight (g) and reproductive characteristics number of flowers per spike, flower size (cm), flower fresh and dry weight (g) were all enhanced with T11 (1.5mmol/L + 50% FC) followed by T10 (1.0mmol/L + 50% FC). Plants without Si application expressed lowest vegetative and reproductive growth under all FC levels especially T0 (100% FC+0.0mmol/L) which showed susceptibility of gladiolus plants to drought conditions of this experiment. From this study it can be recommended that gladiolus can be ideally cultivated under drought conditions and 1.5mmol/L Si is superlative dose for successful plant growth under hot climatic conditions of Cholistan Desert.
Due to anthropogenic activities, heavy metal inputs to the soil have significantly increased. Higher concentrations of toxic metals disturb the sustainability of agricultural productions by affecting the plants’ growth and yield and threatening public health. In the past few decades, silicon (Si) has been introduced as one of the beneficial elements that is involved in the amelioration of various stresses in plants. However, limited studies have focused on the role of Si nanoparticles in the alleviation of heavy metal toxicities in plants. There are several mechanisms involved in the Si-mediated heavy metal toxicity tolerance, which are varied depending on the type of the plant, heavy metal, and duration of the stress imposed. In the present chapter, we will be tried to present the potential functions of heavy metals and the mechanisms involved in the Si/nano Si-mediated amelioration of metal toxicities in plants from different aspects.
Given that the biological treatment of antibiotic wastewater can easily induce resistant bacteria, the photocatalytic degradation of antibiotics is considered as a better method for treating antibiotic wastewater. Therefore, the ability to remove Tylosin (TYL) and Tetracycline (TC) in aqueous solution using rare earth element Tb-doped g-C3N4 under simulated natural solar radiation was investigated. A series of rare earth Tb³⁺ doped mesoporous g-C3N4 were successfully prepared by nitric acid treatment and Tb(NO3)3·5H2O samples showed significantly higher degradation efficiency for TYL and TC than pure g-C3N4. Leaching toxicity experiments were carried out on the catalyst using chard seeds and demonstrated negligible toxicity of the leachate from the catalyst. The structure, elemental state, optical properties, morphology, and photogenerated carrier separation of the prepared xTCN catalysts were characterized by XRD, XPS, UV–Vis DRS, TEM, and PL. The results show that Tb doping enhanced the photocatalytic activity of the g-C3N4 catalyst by narrowing the band gap while improving the light-trapping ability; The separation and transport rate of photogenerated carriers were significantly increased after Tb doping. Finally, a simple, efficient, and non-polluting Tb-doped carbon nitride photocatalyst is successfully developed in this paper.
Plant resistance to drought relies on adaptive strategies based on the timing of phenophases and on the presence of structural traits mainly related to: (1) increase of water uptake and storage; (2) reduction of water loss during dry periods; and (3) mechanical reinforcement of tissues to prevent wilting that may lead to irreversible collapse and damage of cells. In this chapter, after a few evolutionary considerations, we focus on the adaptive value of the main phenological, morphological and anatomical properties. We report the common existence of such traits in both desert and semiarid environments, especially in Mediterranean-type ecosystems. All morpho-anatomical characteristics are interpreted considering that plant resistance to drought also depends on the ability to respond to multiple stressors. We conclude that various combinations of anatomical features can contribute in different degrees to the adaptive capacity of plants to drought.
Chlorophyll fluorescence is closely related to photosystem II (PS II), and chlorophyll fluorescence analysis has become one of the most powerful and widely used techniques that are available to plant physiologists and ecophysiologists. In this article we report the genetic study of leaf chlorophyll fluorescence traits in wheat. 114 wheat recombinant inbred lines (RILs) derived from W-7984×Opata85 were used as samples and QTLs of chlorophyll relative content (C), minimum fluorescence yield of PS II (F o), maximum fluorescence yield of PS II (F m), variable chlorophyll fluorescence yield (F v), maximum quantum yield of PS II (F v /F m), and time of achieving maximum fluorescence yield (T m) were obtained and analyzed. Five QTLs associated with C are detected on 4B, 4D, 6D and 7A, and the relative additive contribution of locus C6D and C7A is 15.60% and 11.04%, respectively; two pairs of interaction loci affecting C are found. Three QTLs are identified for F o on 1A, 1B and 1D. One QTL for F v is mapped on 7D, and it is found that five pairs of interaction QTLs influencing F v . One loci significantly influencing F m is on chromosome 5A, which acts as a major effect gene and can explain 20.69% of total phenotypic variation for F m , and closely links with the RFLP marker Xcdo749. There are six QTLs controlling T m mapped on 2D, 3D, 4A, 4D, 5D and 7D; one pair of interaction QTLs influencing T m exists. Three pairs of interaction QTLs influence F v /F m , showing a general epistatic contribution of 94.62%. The identified QTL markers for chlorophyll fluorescence traits will be useful for understanding the genetics background and marker-assisted selection in wheat photosynthetic traits improving.
Gas exchange, chlorophyll (Chl) fluorescence, and contents of photosynthetic pigments, soluble proteins (ribulose-1,5-bisphosphate carboxylase/oxygenase, RuBPCO), and antioxidant enzymes were characterized in the fully expanded 6th leaves in rice seedlings grown on either complete (CK) or on nitrogen-deficient nutrient (N-deficiency) solutions during a 20-chase period. Compared with the control plants, the lower photosynthetic capacity at saturation irradiance (P
max) was accompanied by an increase in intercellular CO2 concentration (Ci), indicating that in N-deficient plants the decline in P
max was not due to stomatal limitation but due to the reduced carboxylation efficiency. The fluorescence parameters PS2, Fv/Fm, electron transport rate (ETR), and qP showed the same tendency as P
max in N-deficient plants. Correspondingly, a higher qN paralleled the rise of the ratio of carotenoid (Car) to Chl contents. However, Fv/Fm was still diminished, suggesting that photoinhibition did occur in the photosystem 2 (PS2) reaction centres. In addition, the activities of antioxidant enzymes on a fresh mass basis were gradually lowered, leading to the aggravation of membrane lipid peroxidation with the proceeding N-deficiency. The accumulation of malonyldialdehyde resulted in the lessening of Chl and soluble protein content. Analyses of regression showed PS2 excitation pressure (1 - qP) was linearly correlated with the content of Chl and inversely with soluble protein (particularly RuBPCO) content. There was a lag phase in the increase of PS2 excitation pressure compared to the decrease of RuBPCO content. Therefore, the increased excitation pressure under N-deficiency is probably the result of saturation of the electron transport chain due to the limitation of the use of reductants by the Calvin cycle. Rice plants responded to N-deficiency and high irradiance by decreasing light-harvesting capacity and by increasing thermal dissipation of absorbed energy.
Reactive oxygen species (ROS) are produced as a normal product of plant cellular metabolism. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. Despite their destructive activity, they are well-described second messengers in a variety of cellular processes, including conferment of tolerance to various environmental stresses. Whether ROS would serve as signaling molecules or could cause oxidative damage to the tissues depends on the delicate equilibrium between ROS production, and their scavenging. Efficient scavenging of ROS produced during various environmental stresses requires the action of several nonenzymatic as well as enzymatic antioxidants present in the tissues. In this paper, we describe the generation, sites of production and role of ROS as messenger molecules as well as inducers of oxidative damage. Further, the antioxidative defense mechanisms operating in the cells for scavenging of ROS overproduced under various stressful conditions of the environment have been discussed in detail.
The effect of treatment of wheat plants with Cd2+ ions on the photochemical activity of the primary leaves was examined. Three day-old etiolated seedlings were treated with Cd2+ ions for 24 h in dark, and after this treatment the plants were grown in the light until the primary leaves were fully developed. Cd2+ ions (30–120 μM) induced a significant decrease in activities of both photosystem II and photosystem I. The extent of the decrease in PS II activity was much greater than that in the PS I activity. Analysis of changes in the fluorescence yield of chlorophyll α also indicated that Cd2+ ions drastically affect the photochemistry of photosystem II. Cd2+ ions induced decrease in the rates of photoreduction of 2,6-dichlorophenol indophenol even in the presence of the exogenous electron donor, hydroxylamine, both in Tris-treated and untreated chloroplasts. This result suggests that the site of inhibition is near the site of donation of electrons by hydroxylamine. Treatment with Cd2+ ions impairs the electron transport system on the reducing side of PS II. The decrease in the fluorescence yield of Chi α is less than that in the evolution of O2 mediated by oxidized phenylenediamine. This difference may be a result of inhibition on the reducing side of PS II. In addition to inhibition on the reducing side, Cd2+ ions may affect the oxidizing side of PS II. A comparative study of the rates of evolution of O2 with p-benzoquinone and dichloro-p-benzoquinone as electron acceptors was performed since the halogenated benzoquinones have been shown to accept electrons from both active and inactive centers of photosystem II while some of the benzoquinones accept electrons only from active centers. The results suggest that Cd2+ ions induced a marginal increase in the number of inactive reaction centers in PS II. Analysis of light-saturation-kinetics of the evolution of O2 catalysed by PS II indicates a reduction in the size of the antennae as well as in the concentration of the active (α-type) reaction centers of PS II. Thus, the Cd2+-induced effects on the photochemistry of PS II involve changes on the reducing side of PS II as well as possible changes in the sizes of the populations of active and inactive centers. Thus, short-term exposure to Cd2+ ions during establishment of seedlings has a severely detrimental effect on photochemical activities in chloroplasts.
Chromium (Cr) is the second most common metal contaminant in ground water, soil, and sediments due to its wide industrial application, hence posing a serious environmental concern. Among various valence states, Cr(III) and Cr(VI) are the most stable forms. Cr(VI) is the most persistent in the soil and is highly toxic for biota. Since Cr is a non-essential element for plants, there is no uptake mechanism; Cr is taken up along essential elements such as sulfate through sulfate transporters. Cr accumulation in plants causes high toxicity in terms of reduction in growth and biomass accumulation, and Cr induces structural alterations. Cr interferes with photosynthetic and respiration processes, and water and minerals uptake mechanism. Various enzymatic activities related to starch and nitrogen metabolism are decreased by Cr toxicity either by direct interference with the enzymes or through the production of reactive oxygen species. Cr causes oxidative damage by destruction of membrane lipids and DNA damage. Cr may even cause the death of plant species. Few plant species are able to accumulate high amount of Cr without being damaged. Such Cr-tolerant, hyperaccumulator plants are exploited for their bioremediation property. The present review discusses Cr availability in the environment, Cr transfer to biota, toxicity issues, effect on germination and plant growth, morphological and ultrastructural aberrations, biochemical and physiological alterations, effect on metabolic processes, Cr-induced alterations at the molecular level, Cr hyperaccumulation and Cr detoxification mechanism, and the role of arbuscular mycorrhizae in Cr toxicity, in plants.
- ions and to some extent Cl - and SO 4 2 - of Mg 2+ and nutrient imbalance caused by excess of Na + and Cl - ions. Salinity stress response is multigenic, as a number of processes i n- volved in the tolerance mechanism are affected, such as var ious compatible solutes/osmolytes, polyamines, reactive oxygen species and antioxidant defence mecha- nism, ion transport and compartmentalization of inj u- rious ions. Various genes/cDNAs encoding proteins involved in the above-mentioned processes have been identified and isolated. The role of genes/cDNAs e n- coding proteins involved in regulating other genes/ pro- teins, signal transduction process involving hormones like ABA, JA and polyamines, and strategies to i mprove salinity stress tolerance have also been di scussed. EXCESS amount of salt in the soil adversely affects plant growth and development. Nearly 20% of the world's cul- tivated area and nearly half of the world's i rrigated lands are affected by salinity 1
High temperature (HT) stress is a major environmental stress that limits plant growth, metabolism, and productivity worldwide. Plant growth and development involve numerous biochemical reactions that are sensitive to temperature. Plant responses to HT vary with the degree and duration of HT and the plant type. HT is now a major concern for crop production and approaches for sustaining high yields of crop plants under HT stress are important agricultural goals. Plants possess a number of adaptive, avoidance, or acclimation mechanisms to cope with HT situations. In addition, major tolerance mechanisms that employ ion transporters, proteins, osmoprotectants, antioxidants, and other factors involved in signaling cascades and transcriptional control are activated to offset stress-induced biochemical and physiological alterations. Plant survival under HT stress depends on the ability to perceive the HT stimulus, generate and transmit the signal, and initiate appropriate physiological and biochemical changes. HT-induced gene expression and metabolite synthesis also substantially improve tolerance. The physiological and biochemical responses to heat stress are active research areas, and the molecular approaches are being adopted for developing HT tolerance in plants. This article reviews the recent findings on responses, adaptation, and tolerance to HT at the cellular, organellar, and whole plant levels and describes various approaches being taken to enhance thermotolerance in plants.
Laser induced breakdown spectroscopy (LIBS) has
been used to perform in situ analysis of major and minor
elements present in the different parts of the Bermuda grass
(Cynodon dactylon). In situ, point detection/analysis of the
elements in plants without any sample preparation has been
demonstrated. LIBS spectra of the different parts (leaf blade,
leaf sheath and stem) of fresh C. dactylon plant have been
recorded to study the pattern of silica deposition in its
different parts. Atomic lines of Si, Mg, Ca, C, Al, Zn, N, Sr,
etc. have been observed in the LIBS spectra of the C.
dactylon. A close observation of LIBS spectra of the
different parts of the plants shows that silica concentration
is greater in leaf blades than leaf sheaths and stems. The
results obtained with LIBS analysis are also compared with
the number density of phytoliths deposited in different parts
of C. dactylon. It is observed that the highest silicified cell
frequency is present in leaf blades followed by leaf sheaths
and stems which is in close agreement with LIBS analysis.
Hydroponic experiments were conducted to investigate the role of exogenous silicon (Si) addition in increasing hexavalent chromium (Cr VI) tolerance in rice seedlings. Rice seedlings were grown under 100 μM Cr(VI) stress without or with 10 μM Si. Chromium treatment decreased growth, photosynthetic pigments and protein, which was accompanied by a significant increase in Cr accumulation and lipid peroxidation (as malondialdehyde; MDA). However, Si addition alleviated Cr toxicity and promoted growth of rice by decreasing Cr accumulation, root-to-shoot Cr transport and MDA level. Contents of macro (Mg, Ca and K) as well as micronutrients (Zn and Fe) were decreased by Cr except Mn while Si addition prevented decrease in these nutrients induced by Cr. Antioxidant capacity and total phenolic contents were decreased by Cr while these indices improved by Si addition. Treatment of Cr decreased the length of leaf epidermal cells and stomatal frequency, and adversely affected chloroplasts containing mesophyll cells and integrity of xylem and phloem, and Si addition minimized these abnormalities. However, frequency of root hairs was increased by Cr treatment. Results showed that exogenous Si addition enhanced Cr(VI) tolerance in rice seedlings by decreasing Cr accumulation, root-to-shoot Cr transport and MDA level, and by increasing content of some mineral elements (K, Fe and Zn) and antioxidant capacity compared to the Cr treatment alone. © 2011 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.
In this study, the effect of silicon (Si) addition on cadmium (Cd) toxicity in rice seedlings was investigated. After a series of screening experiments, 50 μmol·L−1 of Cd and 10 μ mol·L−1 of Si were selected. Treatment of rice seedlings with Cd (50 μ mol·L−1) resulted in significant accumulation of this metal in roots and shoots. The data revealed that accumulation of Cd resulted in oxidative stress in rice seedlings as evidenced by increased accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA; a peroxidation product of lipids). However, addition of Si (10 μ mol·L−1) together with Cd prevented accumulation of Cd, H2O2 and MDA. Antioxidant capacity was decreased by Cd but enhanced by Si addition. Cd decreased the length and frequency of root hairs, stomatal frequency, and distorted leaf mesophyll cells and vascular bundles. However, addition of Si together with Cd reduced these abnormalities. The results showed that addition of exogenous Si protected rice seedlings against Cd toxicity by preventing Cd accumulation and oxidative stress (H2O2 and MDA accumulation) by increasing Si accumulation and antioxidant capacity, which maintained the structure and integrity of leaf and root.
The effect of excess of cadmium (Cd) on chlorophyll fluores-cence of barley seedlings was studied. The leaves were dark-adapted and then illuminated at 10 different light intensities within the range of 70–1600 µmol.m –2 .s –1 photosynthetically active radiation (PAR). It was found that Cd decreases the chlorophyll fluorescence parameters in dark-adapted leaves: ground (F o), maximal (F m) and variable (F v) fluorescence. However the F v /F m ratio was slightly influenced. At light intensities below 400 µmol.m –2 .s –1 PAR no significant differences between values of photochemical quenching (qP), non-photochemical quenching (qN) and yield of photochemical energy con-version (Y) of control and Cd-treated plants were found. At light intensities about 500 µmol.m –2 .s –1 and higher significant decrease in qP, concomitant increase in qN as well as a reduction in Y were observed. In Cd-treated plants the maximum of apparent electron transport rate (ETR) were reached ear-lier than in control plants and under lower PAR intensities, indicating that the energy consumption by Calvin's cycle reactions is reduced. It is specu-lated that excess of Cd in barley plants causes a down regulation of PSII to avoid over-reduction of primary electron acceptor Q A and to reduce the load on the electron transport chain. Abbreviations: F o , F v and F m – ground, variable and maximal fluorescence of dark-adapted samples; F and F′ m – ground and maximal fluorescence of light-adapted samples; qP – photochemical quenching; qN – non-photo-BULG.
This review describes the fundamentals, instrumentation, applications and future trends of an analytical technique that is in its early stages of consolidation and is establishing its definitive niches among modem spectrometric techniques. The technique has been named Laser Induced Breakdown Spectroscopy (LIBS) and its main characteristic stands in the use of short laser pulses as the energy source to vaporize samples and excite the emission of electromagnetic radiation from its elements and/or molecular fragments. The emitted radiation is analyzed by high resolution optics and the intensities are recorded, usually by fast triggered solid state detectors. Together, these devices allow producing and registering a wide ranging emission spectrum of the short-lived phenomenon induced by the laser pulse. The spectrum contains qualitative and quantitative information which can be correlated with sample identity or can be used to determine the amount of its constituents. This review is divided in four parts. First, the relevant historical and theoretical concepts associated with LIBS are presented; then the main practical aspects of the several experimental and instrumental approaches employed for implementation of the technique are critically described; the applications related in the literature, including those making use of chemometrics, are classified and exemplified with relevant and recently published work. Finally, an attempt to portray an overall evaluation and future perspectives of the technique are presented.
Chlorophyll fluorescence parameters (Chl FPs) derived from the slow (long-term) induction kinetics of modulated Chl a fluorescence are reviewed and analysed with respect to their application in photosynthesis research. Only four mutually independent Chl FPs, calculated from values of five essential Chl fluorescence (ChlF) yields, are distinguished as the basic ones. These are: the maximum quantum yield of PS2 photochemistry (P
O), the photochemical quenching of variable ChlF (qP), the non-photochemical quenching of variable ChlF (qN), and the relative change of minimum ChlF (qO). P
O refers to the dark-adapted state of a thylakoid membrane, qP, qN and qO characterise the light-adapted state. It is demonstrated that all other Chl FPs can be determined using this quartet of parameters. Moreover, three FPs related to the non-radiative energy dissipation within thylakoid membranes are evaluated, namely: the non-photochemical ChlF quenching (NPQ), the complete non-photochemical quenching of ChlF (qCN), and the effective quantum yield of non-photochemical processes in PS2 (N). New FPs, the total quenching of variable ChlF (qTV) and the absolute quenching of ChlF (qA) which allow to quantify co-action of the photochemical and non-photochemical processes during a light period are defined and analysed. The interpretation of Chl FPs and recommendations for their application in the photosynthesis research are also given. Some alternative FPs used in the laboratory practice have only an approximate character and can lead to incorrect conclusions if applied to stressed plants. They are reviewed and compared with the standard ones. All formulae and conclusions discussed herein are verified using experimental values obtained on young seedlings of the Norway spruce (Picea abies [L.] Karst.).
The effect of silicon (Si) nutrition on low-level cadmium (Cd) toxicity symptoms was investigated in hydroponically-grown
rice seedlings (Oryza sativa L.). Silicon (0.0, 0.2, or 0.6mM) was added when seedlings were 6 or 20days old representing early (SiE) or late (SiL) Si treatment, respectively. Cadmium (0.0 or 2.5μM) was added when seedlings were 6days old. Measurements included generation
of CO2 and light response curves; chlorophyll fluorescence analysis; growth; and tissue-element content analysis. Our results showed
that low-level Cd treatment generally inhibited growth and photosynthesis. However, the addition of 0.2 or 0.6mM SiE or SiL significantly reduced root- and leaf-Cd content. Consequently, the addition of 0.6mM SiL significantly alleviated low-level Cd-induced inhibition of growth. Furthermore, 0.2mM Si treatment significantly reduced
g
s compared to 0.0 or 0.6mM Si without inhibiting A, especially in +Cd plants, suggesting an increase in instantaneous water-use-efficiency (IWUE). Additionally, in +Cd plants,
the addition of 0.6mM SiE significantly reduced F
o but increased F
v/F
m, while treatment with 0.2mM SiL significantly increased qP, suggesting an increase in light-use-efficiency. We thus, propose that 0.6mM SiL treatment is required for the alleviation of low-level Cd-mediated growth inhibition. Furthermore, we suggest that 0.2mM
Si concentration might be close to the optimum requirement for maximum Si-induced increase in IWUE in rice plants, especially
when under low-level Cd-stress. Our results also suggest that Si alleviates low-level Cd toxicity by improving light-use-efficiency.
Chlorophyll fluorescence analysis has become one of the most powerful and widely used techniques available to plant physiologists and ecophysiologists. This review aims to provide an introduction for the novice into the methodology and applications of chlorophyll fluorescence. After a brief introduction into the theoretical background of the technique, the methodology and some of the technical pitfalls that can be encountered are explained. A selection of examples is then used to illustrate the types of information that fluorescence can provide.
By treating 0.5 g DW of a plant sample directly with 10 ml of a dilute hydrofluoric acid solution (HF solution, 1.5 M HF-0.6 M HCl), all the silica in plant (as much as 150 mg SiO2) was dissolved within 1 h. After dilution of the extract with 40 mL of distilled water, the silica in the extract was measured by the spectrometric molybdenum yellow method. The molybdenum yellow method, in which silica in 0.1 mL of the diluted extract can be determined in 8 min, is well suited to rapid, micro-estimations of the silica content in plants. In the micromodification, the size of the plant sample was reduced to 100 mg DW. The analytical procedure was simple, and the analytical time was less than 2 h. The method can save much labor and time, compared with the gravimetric analysis. The dissolution with HF solution and the molybdenum yellow method were also applied to the measurement of the content of silica separated by acid digestion of rice plants. Excellent agreement in the silica measurement of rice plants was confirmed among the direct extraction method, the gravimetric method and the digestion-separation-dissolution method. In the molybdenum yellow method, the addition of boric acid enabled to mask the interference of hydrofluoric acid, and the least amount of citric acid required for the elimination of phosphorus interference was proposed. In conclusion in this report, recommended methods for the rapid estimation of the silica content in rice plants were presented.
In 1931, using their eyes as instruments, H . Kautsky and A . Hirsch related the time course of chlorophyll a fluorescence with photosynthesis in a less-than-one-page article in Naturwissenschaften (see Kautsky's photograph). Chlorophyll a fluorescence is now being used by hundreds of investigators as a probe for various aspects of photosynthesis-from excitation energy transfer in picosecond time scale to CO2 fixation in minutes . It is not only a much used, but also a much abused, tool. It is used because of it being a non-invasive, rapid and a highly sensitive probe, and misused because it is sometimes not recognised that it is affected by various photosynthetic and other reactions. I submit that, like any other technique, if it is used with care and with due regard for its time dependence and competing parameters. it will remain as the one-most powerful tool for probing excitation energy transfer, primary photochemistry, electron flow on both the donor and the acceptor side of photosystem II (PSII) of oxygenic PSII. Further, it is very useful in the quick assay of PSII mutations, and down- regulation and other adjustments to stress (excess light, heat, heavy metal, nutrients and certain herbicides). In this paper, I will present my viewpoint, not a review, on the conceptual and experimental developments in this field. Whenever appropriate, and without any shame and humility, I will include some of my involvement in the excitement surrounding this field. I hope that this paper will serve as a starting point for further discussion of not only the history, but the practical use of chlorophyll a fluorescence as an intrinsic probe of stresses to plants, as well as individual reactions of oxygenic photosynthesis, when combined with other parallel measurements.
Silicon (Si) plays important roles in alleviating various abiotic stresses. In rice (Oryza sativa), arsenic (As) is believed to share the Si transport pathway for entry into roots, and Si has been demonstrated to decrease As concentrations. However, the physiological mechanisms through which Si might alleviate As toxicity in plants remain poorly elucidated. We combined detailed gas exchange measurements with chlorophyll fluorescence analysis to examine the effects of Si nutrition on photosynthetic performance in rice plants (a wild-type cultivar and its lsi1 mutant defective in Si uptake) challenged with As (arsenite). As treatment impaired carbon fixation (particularly in the wild-type genotype) that was unrelated to photochemical or biochemical limitations but, rather, was largely associated with decreased leaf conductance at the stomata and mesophyll levels. Indeed, regardless of the genotypes, in the plants challenged with As, photosynthetic rates correlated strongly with both stomatal (r(2) = 0.90) and mesophyll (r(2) = 0.95) conductances, and these conductances were, in turn, linearly correlated with each other. The As-related impairments to carbon fixation could be considerably reverted by Si in a time- and genotype-dependent manner. In conclusion, we identified Si nutrition as an important target in an attempt to not only decrease As concentrations but also to ameliorate the photosynthetic performance of rice plants challenged with As.
Cultivated rice (Oryza sativa) accumulates high concentration of silicon (Si), which is required for its high and sustainable production. High Si accumulation in cultivated rice is achieved by a high expression of both influx (Lsi1) and efflux (Lsi2) Si transporters in roots. Herein, we physiologically investigated Si uptake, isolated and functionally characterized Si transporters in six wild rice species with different genome types. Si uptake by the roots was lower in Oryza rufipogon, Oryza barthii (AA genome), Oryza australiensis (EE genome) and Oryza punctata (BB genome), but similar in Oryza glumaepatula and Oryza meridionalis (AA genome) compared with the cultivated rice (cv. Nipponbare). However, all wild rice species and the cultivated rice showed similar concentration of Si in the shoots when grown in a field. All species with AA genome showed the same amino acid sequence of both Lsi1 and Lsi2 as O. sativa, whereas species with EE and BB genome showed several nucleotide differences in both Lsi1 and Lsi2. However, proteins encoded by these genes also showed transport activity for Si in Xenopus oocyte. The mRNA expression of Lsi1 in all wild rice species was lower than that in the cultivated rice, whereas the expression of Lsi2 was lower in O. rufipogon and O. barthii but similar in other species. Similar cellular localization of Lsi1 and Lsi2 was observed in all wild rice as the cultivated rice. These results indicate that superior Si uptake, the important trait for rice growth, is basically conserved in wild and cultivated rice species.
We studied the long-term effect of nutrient management on soil fertility and soil organic carbon (SOC) pools under a 6-year-old pearl millet–wheat cropping system in an Inceptisol of subtropical India. Significant build-up in soil fertility in terms of alkaline KMnO4-N, Olsen-P, NH4OAc-K and CaCl2-S as well as SOC pools namely, total organic carbon (TOC), Walkley and Black organic carbon (WBC), labile organic carbon (LBC) and microbial biomass carbon (MBC) were maintained under FYM and integrated nutrient management involving FYM and NPK than unfertilized control plot in 0–15 and 15–30 cm soil depths. The highest values of TOC (11.48 g kg−1) and WBC (7.86 g kg−1) were maintained in FYM treated plot, while the highest values of LBC (1.36 g kg−1) and MBC (273 mg kg−1) were found in FYM + NPK. The magnitude of change in pools of SOC in sub-surface (15–30 cm) soil was low as compared to the surface soil (0–15 cm). Significant increase in all the pools of SOC in FYM treated plots indicates the importance of application of organic manure like FYM in maintaining organic carbon in soil. Highly strong relationships were exhibited between LBC and MBC with yield, indicating that these pools are more important for nutrient turn-over and their availability to plants than total SOC. Carbon management index revealed that integrated nutrient management could be followed for enhancing crop productivity, nutrient availability and soil carbon pools for long-term. These results conclude that for sustainable crop production and maintaining soil quality, input of organic manure like FYM is of major importance and should be advocated in the nutrient management of intensive cropping system for improving soil fertility and biological properties of soils.
A mass spectrometric 16O2/18O2 technique was used to determine the rate of gross O2 evolution in attached leaves of Triticum aestivum under several environmental conditions. Simultaneously, fluorescence emission was determined from the upper and the lower sides of the leaf. The rate of non-cyclic electron flow derived from gross O2 evolution deviated from the rates predicted from fluorescence measurements. This deviation varies depending on environmental conditions and on the side on which the leaf fluorescence is being measured. Our data clearly indicate that fluorescence measurements provide trends in electron transport but do not yield accurate electron transport rates of the entire leaf.
Seedlings of Picea abies (L.) Karst. were grown in nutrient solutions containing a range of Pb concentrations. A 4-week exposure to 0.5 μM Pb reduced the growth of primary, secondary and tertiary roots. The initiation of lateral roots appeared to be more sensitive to Pb than the growth of already formed roots. After a 9-week exposure to a range of Pb concentration (0.1-2 μM) the levels of Pb in roots increased with increasing Pb supply. The Pb levels in roots were higher than in needles by a factor of 100-300. The Pb levels in roots were strongly dependent upon the pH of the nutrient solution and decreased at lower pH. With the exception of decreased levels of Ca, Fe and Zn in root tips (5 mm) exposure to Pb only slightly affected the levels of other mineral elements in the roots. In needles, the Ca and Mn levels decreased after exposure to all Pb concentrations.
Modification of PSII photochemistry in nitrogen deficient maize and wheat plants was investigated. Fluorescence quenching analyses showed that nitrogen deficiency induced decreases in the quantum yield of PSII electron transport, the efficiency of excitation energy capture by open PSII reaction centers, and the photochemical quenching, but an increase in the non-photochemical quenching. The analyses of the polyphasic rise of fluorescence transients demonstrated that nitrogen deficiency decreased the efficiency with which a trapped exciton can move an electron into the electron transport chain further than QA and the quantum yield of electron transport beyond QA, while it increased the absorption and trapping fluxes per PSII reaction center. Nitrogen deficiency also resulted in a decrease in the absorption, trapping and electron transport fluxes per leaf cross section as well as a decrease in the concentration of active PSII reaction centers. The comparisons between fluorescence parameters and photosynthetic CO2 assimilation and growth rates suggest that fluorescence quenching analysis and the JIP test derived from the polyphasic rise of fluorescence transient can be a useful tool for assessing the physiological effects of N deficiency on plants.
Hydroponic experiments were conducted to investigate whether exogenous addition of nitric oxide (NO) as sodium nitroprusside (SNP) alleviates arsenic (As) toxicity in Luffa acutangula (L.) Roxb. seedlings. Arsenic (5 and 50 μM) declined growth of Luffa seedlings which was accompanied by significant accumulation of As. SNP (100 μM) protected Luffa seedlings against As toxicity as it declined As accumulation significantly. The photosynthetic pigments and chlorophyll fluorescence parameters such as Fv/Fm, Fv/F0, Fm/F0 and qP were decreased while NPQ was raised by As. However, the toxic effects of As on photosynthesis were significantly ameliorated by SNP. The oxidative stress markers such as superoxide radical, hydrogen peroxide and malondialdehyde (lipid peroxidation) contents were enhanced by As, however, these oxidative indices were diminished significantly in the presence of SNP. As treatment stimulated the activities of SOD and CAT while the activities of APX and GST, and AsA content and AsA/DHA ratio were decreased. Upon SNP addition, along with further rise in SOD and CAT activity, APX and GST activity, and levels of AsA and AsA/DHA ratio were restored considerably. Overall results revealed that significant accumulation of As suppressed growth, photosynthesis, APX and GST activities and decreased AsA content, hence led to the oxidative stress. However, the addition of SNP protected seedlings against As stress by regulating As accumulation, oxidative stress and antioxidant defense system.
Biotic systems face immense environmental hazards such as accumulation of heavy metals, particularly in agricultural ecosystems that might cause deterioration of yield and quality of crops. In this study, we evaluated the role of silicon (Si) in alleviating the heavy metal (Cd) stress tolerance in cotton by analyzing the induced Physio-chemical changes. Cotton plants were grown in hydroponic culture with three different Cd levels (0, 1 and 5μM) along with two Si treatment levels (0 and 1mM). The data showed that Cd alone reduced the plant growth as well as the efficiency of antioxidant activity as compared to control plants. Plant growth, gas exchange characteristics (net photosynthetic rate, stomatal conductance, transpiration rate, water use efficiency) chlorophyll contents, and carotenoids as well as the performance of antioxidant enzymes were improved by the exogenous application of Si. The adverse effects of Cd on plant growth were alleviated by the exogenous application of Si. It was observed that Si effectively mitigated the adverse effects of Cd on cotton plants and markedly enhanced the growth, biomass and photosynthetic parameters while decreased the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and electrolytic leakage (EL). The antioxidant enzyme activities in cotton leaves and roots increased significantly, when Si was added to control as well as Cd stressed plants. In conclusion, Si improved the growth and photosynthesis attributes of cotton plants by mitigating the adverse effects of Cd stress through reduced EL, MDA and H2O2 contents and improved activities of antioxidant enzymes.
The quantification of silicon (Si) in plant samples is being requested more frequently, especially in agricultural laboratories associated with the determination of nutritional requirements of sugarcane (Saccharum officinarum L.) and rice (Oryza sativa L.). The analysis of plant material for Si can be protracted, especially if laboratories do not have access to X‐ray flourescence (XRF) instrumentation and large numbers of samples are involved. A simplified procedure using equipment considered standard in most agricultural laboratories is reported. Dry, ground plant material is subjected to nitric acid/peroxide oxidation in a low‐pressure laboratory microwave digestion system. The hydrated silica liberated from the organic matrix is dissolved in a small volume of sodium hydroxide solution also using the microwave digestion system. Silicon is measured by inductively coupled plasma atomic emission spectrometry (ICP‐AES). This method gives results that are linearly correlated with the much slower conventional techniques and avoids using hazardous chemicals (hydrofluoric acid) sometimes employed in other microwave methods.
Hydroponic experiments were conducted to investigate whether exogenous addition of nitric oxide (NO) as sodium nitroprusside (SNP) alleviates arsenic (As) toxicity in Luffa acutangula (L.) Roxb. seedlings. Arsenic (5 and 50 µM) declined growth of Luffa seedlings which was accompanied by significant accumulation of As. SNP (100 µM) protected Luffa seedlings against As toxicity as it declined As accumulation significantly. The photosynthetic pigments and chlorophyll fluorescence parameters such as Fv/Fm, Fv/F0, Fm/F0 and qP were decreased while NPQ was raised by As. However, the toxic effects of As on photosynthesis were significantly ameliorated by SNP. The oxidative stress markers such as superoxide radical, hydrogen peroxide and malondialdehyde (lipid peroxidation) contents were enhanced by As, however, these oxidative indices were diminished significantly in the presence of SNP. As treatment stimulated the activities of SOD and CAT while the activities of APX and GST, and AsA content and AsA/DHA ratio were decreased. Upon SNP addition, along with further rise in SOD and CAT activity, APX and GST activity, and levels of AsA and AsA/DHA ratio were restored considerably. Overall results revealed that significant accumulation of As suppressed growth, photosynthesis, APX and GST activities and decreased AsA content, hence led to the oxidative stress. However, the addition of SNP protected seedlings against As stress by regulating As accumulation, oxidative stress and antioxidant defense system.
The response of the antioxidant enzymes and metabolites of the ascorbate glutathione pathway to oxidative stress caused by equal concentration (50μM) of Cr(III) and Cr(VI) was studied in 15-day-old seedlings of green gram (Vigna radiata (L.) R.Wilczek. cv CO 4) for 5 days after imposition of stress. Significant increase in lipid peroxidation and H2O2 generation was seen 5h after stress in Cr(VI) as against 12h in Cr(III)-treated plants. High rate of uptake and translocation of Cr was seen in the first 12h of treatment with roots retaining 80 times more Cr than the shoots in both the speciation. No significant increase in catalase (CAT) activity and monodehydroascorbate reductase (MDHAR) was observed under Cr(III). Superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities increased under Cr(VI) after 12 and 4h, respectively. Under Cr(VI) stress there was a steep increase of 194.6nMg−1 FW in the ascorbic acid (AA) content between 5 and 24h of treatment. In contrast to reduced glutathione (GSH) content, which reduced after 24h after treatment, oxidized glutathione (GSSG) increased steadily through the course of the experiment under both speciation. The rate of decline in the GSH/GSSG ratio was much faster in Cr(III) than Cr(VI). Results suggest differential response to AA and H2O2 signaling by Cr(III) and Cr(VI) and that AA in combination with APX was more effective in mitigating oxidative stress as against the role of GSH as an antioxidant.
This paper deals with the photosynthetic effects of a range of heavy metals on the seagrass Halophila ovalis. In this study, the photosynthetic response of laboratory-cultured H. ovalis to four heavy metals (Cu, Cd, Pb, Zn) was investigated. The results indicated clearly that chlorophyll a fluorescence was effective in monitoring the onset and development of stress, and occasional recovery, of H. ovalis when exposed to a wide range of heavy metals. Heavy metals in concentrations from 1 to 10 mg litre−1 produced several acute toxic responses. They had a variety of effects on the photosynthetic processes of this seagrass, with Cu and Zn having substantially greater effects than Pb and Cd. Quantum yield was the most sensitive measure of the photosynthetic processes affected by all heavy metals tested. With some exceptions, photosynthetic pigment content generally confirmed the chlorophyll a fluorescence responses.
Metal (Pb, Zn and Fe2+) tolerances, root anatomy and profile of radial oxygen loss (ROL) along the root (i.e., spatial pattern of ROL) were studied in 10 emergent wetland plants. The species studied could be classified into three groups. Group I included Alternanthera philoxeroides, Beckmannia syzigachne, Oenanthe javanica and Polypogon fugax, with high ROL along the whole length of root (‘partial barrier’ to ROL). Group II included Cyperus flabelliformis, Cyperus malaccensis, Juncus effusus, Leersia hexandra and Panicum paludosum, ROL of which was remarkably high just behind the root apex, but decreased significantly at relatively basal regions (‘tight barrier’ to ROL). Group III consisted of only Neyraudia reynaudiana, with extremely low ROL along the length of root. The results indicated that metal tolerance in wetland plants was related to root anatomy and spatial pattern of ROL. Co-evolution of metal (Fe and Zn) tolerance and flood tolerance possibly developed in wetland plants since species showing a ‘tight barrier’ to ROL (a common trait of flood-tolerant species) in basal root zones had higher Fe and Zn tolerances than those showing a ‘partial barrier’. Root anatomy such as lignin and suberin deposition contributed to a ‘tight barrier’ in root and conferred to exclusion ability in tolerant species.
Laser induced breakdown spectroscopy (LIBS) is basically an emission spectroscopy technique where atoms and ions are primarily formed in their excited states as a result of interaction between a tightly focused laser beam and the material sample. The interaction between matter and high-density photons generates a plasma plume, which evolves with time and may eventually acquire thermodynamic equilibrium. One of the important features of this technique is that it does not require any sample preparation, unlike conventional spectroscopic analytical techniques. Samples in the form of solids, liquids, gels, gases, plasmas and biological materials (like teeth, leaf or blood) can be studied with almost equal ease. LIBS has rapidly developed into a major analytical technology with the capability of detecting all chemical elements in a sample, of real- time response, and of close-contact or stand-off analysis of targets. The present book has been written by active specialists in this field, it includes the basic principles, the latest developments in instrumentation and the applications of LIBS . It will be useful to analytical chemists and spectroscopists as an important source of information and also to graduate students and researchers engaged in the fields of combustion, environmental science, and planetary and space exploration. * Recent research work * Possible future applications * LIBS Principles.
The present study investigated impact of exogenous application of indole acetic acid (IAA; 10 and 100μM) in pea seedlings under hexavalent chromium (Cr VI; 50, 100 and 250μM). Cr and 100μM IAA alone as well as in combination decreased seed germination rate compared to control. However, under Cr phytotoxicity, addition of 10μM IAA recovered seed germination rate to the level of control. Exposure of pea seedlings to Cr and 100μM IAA during their early stage caused decrease in fresh mass, length, protein and nitrogen contents of roots and shoots compared to control. Treatment of pea seedlings with Cr resulted in a rapid accumulation of this metal in roots and shoots. Moreover, addition of 100μM IAA together with Cr, further increased accumulation of this metal in roots and shoots compared to Cr treatments alone. Treatment of pea seedlings with Cr and 100μM IAA, resulted in a marked decrease in nitrate reductase, nitrite reductase, glutamine synthetase and glutamate synthase (GOGAT) activities (except 50μM Cr alone for GOGAT), and an increase in ammonium content and glutamate dehydrogenase activity. Parameters related with oxidative stress, i.e. superoxide radicals and reactive carbonyl groups (protein oxidation) were increased by Cr and 100μM IAA compared to control. By contrast, addition of 10μM IAA together with Cr, alleviated negative effect of Cr on growth, protein, nitrogen and nitrogen metabolism, and led to decrease in oxidative injuries caused by Cr. The data indicate that 10μM IAA protects pea seedlings during the early growth period against Cr phytotoxicity by regulating Cr accumulation and oxidative damage. However, addition of 100μM IAA together with Cr showed opposite responses.
Low Si content of rice (Oryza sativa L.) straw is known to be associated with poor rice grain yields, and the need for Si fertilization can be assessed on the basis of the Si content of rice straw. Current methodologies for determining Si in plant tissue are tedious and slow and/or involve cumbersome safety precautions. A new method [autoclave-induced digestion (AID)] has been developed. Plant tissue is digested with H2O2 and NaOH in an autoclave, and Si is determined by standard colorimetric techniques that can be automated. For rice straw ranging in Si content from < 1 to > 5%, the AID method was linearly correlated (r = 0.999) with Si determination by NaOH fusion, with an intercept near zero and a slope near 1.
Understanding the matrix effects in laser plasma spectroscopy is of considerable importance, since these effects actually limit the performance of the method. Thus, a new multifiber imaging spectrometer, coupled with an ICCD detection system, was developed and applied to this task. A special sample holder which enables simultaneous observation of single-shot plasmas through eight optical fibers was constructed. The fibers collect the emission at several locations from single-shot plasma, perpendicularly to its expansion axis. In this way, high-resolution spectra of the analyte and the matrix are simultaneously obtained with spatial and temporal resolutions. Results on investigation of matrix effects in analysis of Pb in natural soils, using this setup, are reported. The matrix effect due to the sand content in the examined samples is presented, and explanations are suggested. It was found that the optimum location in the plasma for spectral analysis depends on analyte concentration in such a way that, at higher concentration ranges, the spectra should be measured closer to the surface. A clear global optimum was observed for analyte signal as a function of location and time, indicating the best experimental conditions. The matrix dependence of that optimum is addressed. The spatial distribution of the internal plasma temperature and the related matrix effects are also discussed.
By treating 0.5 g DW of a plant sample directly with 10 ml of a dilute hydrofluoric acid solution (HF solution, 1.5 M HF—0.6 M HCl), all the silica in plant (as much as 150 mg SiO2) was dissolved within 1 h. After dilution of the extract with 40 mL of distilled water, the silica in the extract was measured by the spectrometric molybdenum yellow method. The molybdenum yellow method, in which silica in 0.1 mL of the diluted extract can be determined in 8 min, is well suited to rapid, micro-estimations of the silica content in plants. In the micro-modification, the size of the plant sample was reduced to 100 mg DW. The analytical procedure was simple, and the analytical time was less than 2 h. The method can save much labor and time, compared with the gravimetric analysis. The dissolution with HF solution and the molybdenum yellow method were also applied to the measurement of the content of silica separated by acid digestion of rice plants. Excellent agreement in the silica measurement of rice plants was confirmed among the direct extraction method, the gravimetric method and the digestion-separation-dissolution method. In the molybdenum yellow method, the addition of boric acid enabled to mask the interference of hydrofluoric acid, and the least amount of citric acid required for the elimination of phosphorus interference was proposed. In conclusion in this report, recommended methods for the rapid estimation of the silica content in rice plants were presented.
Irradiation of Spinach oleracea intact leaf tissue and of mesophyll protoplasts of Valerianella locusta at 20° C with strong light resulted in severe (40–80%) inhibition of photosynthesis, measured as photosystem II electron transport activity in isolated thylakoids or as fluorescence parameter FV/FM on intact leaf disks. No net degradation of the D1 protein of photosystem II was seen under these conditions. However, in the presence of streptomycin, an inhibitor of chloroplast protein synthesis, net D1 degradation (up to about 80%) did occur with a half-time of 4–6h, and photoinhibition was enhanced. Thylakoid ultrastructure remained stable during photoinhibition, even when substantial degradation of D1 took place in the presence of streptomycin. When leaf disks were irradiated at 2°C, streptomycin did not influence the degree of photoinhibition, and net Dl degradation did not occur. These results suggest that in excess (photoinhibitory) light at 20°C, turnover (coordinated degradation and synthesis) of D1 diminished the degree of photoinhibition. The observed photoinhibition is thought to be due to the accumulation of inactive photosystem II reaction centres still containing D1. In the presence of streptomycin, the Dl protein was degraded (probably in the previously inactivated centres), but restoration of active centres via D1 synthesis was blocked, leading to more severe photoinhibition. Low temperature (2°C), by restricting both degradation and resynthesis of D1, favoured the accumulation of inactive centres. Streptomycin and chloramphenicol (another inhibitor of chloroplast protein synthesis) were tested for side-effects on photosynthesis. Strong inhibitory effects of chloramphenicol, but much less severe effects of streptomycin were observed.
Using a femtosecond laser-based technique, spectrochemical analysis of leaf samples is demonstrated. The study is exemplified for Fe. Standard reference concentrations – internal standards – of Fe in the two leaf samples were measured using the method of Relaxation Weighted Magnetic Resonance Imaging. From the spectra obtained using Laser Induced Breakdown Spectroscopy technique, spatial distribution of Fe within the leaf was identified. Thus, this technique could potentially be used as a complementary technique for identification of storage and trafficking of iron ions within different plant compartments. In particular, individual plant cells can be investigated without collateral damage with high spatial distribution. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
This article reports on the utilization of X-ray microradiography and laser induced breakdown spectroscopy (LIBS) techniques for investigation of the metal accumulation in different part of leaf samples. The potential of the LIBS-analysis for finding the proper plant species for phytoremediation is compared with the results of microradiography measurements at the HERCULES source at ENEA, Rome (Italy) and X-ray microradiography experiments at the ELETTRA Synchrotron, Trieste (Italy). Microsc. Res. Tech., 2007. © 2006 Wiley-Liss, Inc.
Chlorophyll a fluorescence characteristics were investigated in 12 species and 2 hybrids from the genus Flaveria exhibiting C3, C3–C4 intermediate, or C4 photosynthesis, and in the C4 species Zea mays. At room temperature, the variable fluorescence divided by the maximum fluorescence (FV/FM) of dark-adapted leaves decreased from C3 to C4 plants. This trend was qualitatively paralleled by an increase of the 735 nm peak relative to the 685 nm peak (F735/F685) of fluorescence emission spectra measured at low temperature (77 K). The variations were analysed using a quantitative model that takes into account higher PS I fluorescence in C4 plants than in C3 plants. The model predicts a linear correlation between 1/(FV/FM) and F735/F685, and was experimentally confirmed. From linear regression analysis, the FV/FM of PS II was calculated to be 0.88. By comparing the FV/FM of PS II with the FV/FM from leaves, the PS I contribution to total F0 fluorescence at wavelengths greater than 700 nm was determined to be about 30% and 50% in C3 and C4 plants, respectively. The corresponding values for the FM fluorescence were 6% and 12%. It is concluded that the effects of PS I fluorescence are significant and should be taken into account when analysing fluorescence data.
Single-pulse Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Ablation Inductively Coupled Plasma Mass-Spectrometry (LA-ICP-MS)
were applied for mapping the silver and copper distribution in Helianthus Annuus L. samples treated with contaminant in controlled conditions. For Ag and Cu detection the 328.07 nm Ag(I) and 324.75 nm Cu(I)
lines were used, respectively. The LIBS experimental conditions (mainly the laser energy and the observation window) were
optimized in order to avoid self-absorption effect in the measured spectra. In the LA-ICP-MS analysis the Ag 107 and Cu 63
isotopes were detected. The capability of these two analytical techniques for high-resolution mapping of selected trace chemical
elements was demonstrated.
Elemental determinations are usually performed on plant samples for agronomic or environmental studies. Direct solid sampling is possible when electrothermal vaporization (ETV) is used as a method of sample introduction in inductively coupled plasma atomic emission spectrometry (ICP-AES). ETV-ICP-AES was applied for elemental determinations in plant samples. The first application aimed at Cd determinations in very small size plant material samples. Several reference plant materials were used to validate the accuracy of the method. Quality control included the systematic analysis of a reference sample in each batch of unknown samples. The performance of the method in time was illustrated by a control chart. The second application aimed at the content of Si in plant materials. Quantification of Si in plant samples was carried out using samples issued from an inter-laboratory test. Detection limit of 30 μg g− 1 was achieved for Si. In all cases, quantification was accomplished easily by means of aqueous standard solutions deposited on cellulose support.
We report on the development and implementation of analytical methodology for investigating elemental accumulation in different layers within plant leaves, with in-situ spatial resolution mapping, exploiting the technique of LIBS. The spectrochemical analysis of lead-doped leaf samples is demonstrated to develop a real time identification procedure in order to complement other analytical techniques not lending themselves for spatial resolution analysis. Our findings suggest that with elevated levels of Pb within the plants transportation and storage of some nutrition elements is changed.