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The Water-Culture Method for Growing Plants Without Soil
... After the rooting of minicuttings, the seedlings received 5 mL of water for 20 days. Next, with the seedlings measuring 55 cm in height, the application of 10 mL daily nutrient solution -P [26] was started with modification of the Fe source to Fe-EDDHMA, and the pH adjusted to 5.0 ± 0.5 with the use of NaOH (1 M) or HCl (1 M) solution. Initially, the nutrient solution was applied for a 7-day period, at 25% of the concentration indicated by Hoagland and Arnon [26]. ...
... Next, with the seedlings measuring 55 cm in height, the application of 10 mL daily nutrient solution -P [26] was started with modification of the Fe source to Fe-EDDHMA, and the pH adjusted to 5.0 ± 0.5 with the use of NaOH (1 M) or HCl (1 M) solution. Initially, the nutrient solution was applied for a 7-day period, at 25% of the concentration indicated by Hoagland and Arnon [26]. Afterward, the solution concentration was increased to 50% for one week and then to 75%, which was kept until the end of the experimental period. ...
... The experiment was developed in a completely randomized design in a 3 × 2 factorial scheme, with three concentrations of P: 0.1 mM under dose, 0,1 mM (under dose), 1,0 mM (adequate dose), and 10 mM (overdose) in the absence and presence (2 mmol L − 1 ) of Si. Phosphorus concentrations were based on the recommendation of Hoagland and Arnon [26] corresponding to 10, 100, and 1000% of the recommended value, respectively. Potassium phosphate (KH 2 PO 4 ) was used as a P source, and the K content was balanced across treatments by adding potassium chloride. ...
Background
Nutritional disorders of phosphorus (P), due to deficiency or toxicity, reduce the development of Eucalyptus spp. seedlings. Phosphorus deficiency often results in stunted growth and reduced vigor, while phosphorus toxicity can lead to nutrient imbalances and decreased physiological function. These sensitivities highlight the need for precise management of P levels in cultivation practices. The use of the beneficial element silicon (Si) has shown promising results under nutritional stress; nevertheless, comprehensive studies on its effects on Eucalyptus spp. seedlings are still emerging. To further elucidate the role of Si under varying P conditions, an experiment was conducted with clonal seedlings of a hybrid Eucalyptus spp. (Eucalyptus grandis × Eucalyptus urophylla, A207) in a soilless cultivation system. Seedlings were propagated using the minicutting method in vermiculite-filled tubes, followed by treatment with a nutrient solution at three P concentrations: a deficient dose (0.1 mM), an adequate dose (1.0 mM) and an excessive dose (10 mM), with and without the addition of Si (2mM). This study assessed P and Si concentration, nutritional efficiency, oxidative metabolism, photosynthetic parameters, and dry matter production.
Results
Si supply increased phenolic compounds production and reduced electrolyte leakage in seedlings provided with 0.1 mM of P. On the other hand, Si favored quantum efficiency of photosystem II as well as chlorophyll a content in seedlings supplemented with 10 mM of P. In general, Si attenuates P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters in seedlings of Eucalyptus grandis × Eucalyptus urophylla.
Conclusion
The results of this study indicate that Eucalyptus grandis × Eucalyptus urophylla seedlings are sensitive to P deficiency and toxicity and Si has shown a beneficial effect, attenuating P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters.
... Hyperspectral data often has hundreds or even thousands of wavelength points, which not only provides rich information about samples but also poses challenges for computer storage, transmission, and data processing (Arnon and Hoagland, 1938). When extracting spectral dimension information from hyperspectral data for modeling, using full band spectral information to establish the model will bring various negative impacts to the model due to the presence of uninformative variables in the data (Gruber et al., 2013). ...
... The dimension reduction algorithm can select the wavelength variables that are more meaningful to the classification results from the full wavelength range and eliminate redundant wavelengths. It could improve the prediction accuracy and modeling calculation efficiency of the model, as well as reducing the overfitting of the model and improve the generalization ability of the model (Arnon and Hoagland, 1938;Gruber et al., 2013;Khan et al., 2018). ...
Introduction
The micronutrient deficiency of iron and boron is a common issue affecting the growth of rapeseed (Brassica napus). In this study, a non-destructive diagnosis method for iron and boron deficiency in Brassica napus (genotype: Zhongshuang 11) using hyperspectral imaging technology was established.
Methods
The recognition accuracy was compared using the Fisher Linear Discriminant Analysis (LDA) and Support Vector Machine (SVM) recognition models. Recognition results showed that Multiple Scattering Correction (MSC) could be applied for the full band hyperspectral data processing, while the LDA models presented better performance on establishing the leaf iron and boron deficiency symptom recognition than the SVM models.
Results
The recognition accuracy of the training set reached 96.67%, and the recognition rate of the prediction set could be 91.67%. To improve the model accuracy, the Competitive Adaptive Reweighted Sampling algorithm (CARS) was added to construct the MSC-CARS-LDA model. 33 featured wavelengths were selected via CARS. The recognition accuracy of the MSC-CARS-LDA training set was 100%, while the recognition accuracy of the MSC-CARS-LDA prediction set was 95.00%.
Discussion
This study indicates that, it is capable to identify the iron and boron deficiency in rapeseed using hyperspectral imaging technology.
... As shown in Figure 1, the experimental design was divided into four parts. In accordance with the plant chemical analysis method [37], two hundred lettuce plants at each growth stage (1, 20, and 35 days after transplanting) from the station were selected for the determination of their N, P, K, Ca, and Mg contents. The sample leaves were dried and crushed, and then the contents (mg·g −1 ) of N, K, P, Ca, and Mg were measured. ...
... The digestion method and hydrochloric acid extraction method were used to determine the contents of macronutrients in the lettuce leaves [38]. The contents of chlorophyll and carotenoids in the lettuce plants were determined through ethanol acetone extraction [37]. Anthrone colorimetry and the salicylic acid method were used to determine the soluble sugar content and nitrate content in the lettuce plants. ...
In order to precisely obtain the impact of nutritional elements on lettuce yield and quality, in the present study, a nutrient solution formula suitable for lettuce hydroponic production was development using response surface methodology based on the determination for micro-elements in three growth stages and taking the interaction between elements into account. Then, the formula was optimized and validated, aiming for the goal of improving lettuce yield and quality. The results showed that 200 healthy lettuce leaves contained similar amounts of macro-elements, and there was no significant difference in the unit content of micro-elements among the seedling, rosette, and harvest stages. Quadratic regression models between shoot fresh weight, SPAD value, soluble sugar content, Vc content, and nutrient content were established (R2 = 0.91, 0.95, 0.98, and 0.81, respectively). The optimal concentrations of P, K, Ca, and Mg obtained by multi-objective optimization of the quadratic regression models for fresh weight, SPAD value, soluble sugar content, and Vc content were 2.71 mmol·L−1, 6.42 mmol·L−1, 5.58 mmol·L−1, and 7.11 mmol·L−1, respectively. The nutrient solution formula (T1) was found to be the optimal nutrient solution formula for improving lettuce growth and quality. Overall, we developed a specific and targeted nutrient solution formulation for lettuce; this formulation not only meets lettuce’s demand for nutrients, but also improves lettuce yield and quality, providing more choices for lettuce production in a region with high salts and high pH in the irrigation water.
... Only a 15% loss in nitrogen concentration can be observed for the continuous run, while the organic carbon is sufficiently removed even with increases in the HRT. The N content in the polished product is >220 mg/L NH 4 + -N, which is higher than a standard Hoagland medium, which contains roughly 210 mg/L total N [52]. In addition, with the remaining-NO 3 -N, the total N of the polished product is increased, which would make it suitable for systems which make use of a full-strength Hoagland medium, which, as previous findings show, most hydroponic systems use [53]. ...
... The data for the continuous run show that whatever organic carbon is added is rapidly utilised, while the N content in the polished product remains high and on par with a Hoagland medium [52]. The analysis shows that even with the continued addition of LD, the organic carbon is rapidly taken up, as the TOC values remained below 100 mg/L from day 10 onwards. ...
Nutrient pollution-mainly nitrogen and phosphorus-caused by organic waste continues to impact the environment. The implementation of a circular economy is integral to alleviating these effects. Liquid digestate, which is a byproduct of anaerobic digestion (a waste-valorising process), is a nutrient-dense organic fertiliser with vast applications in agriculture. Using an aerobic polishing unit, this study developed a viable method for the preparation of a hydroponic fertiliser by investigating the effect of pH on the nutrient recycling capabilities of said system. The heterotrophic bacteria present in the biofilm, identified by 16S gene sequencing, are responsible for 90% of organic carbon (as TOC) removal with minimal ammonium loss. This is ideal for promoting optimal nitrification in hydroponic systems in the absence of organic carbon to ensure plant growth is not affected. Although pH 8 was found to be ideal for batch operation, this pH condition resulted in decreased microbial longevity and, therefore, increased ammonification due to microbial decay. Therefore, continuous operation at pH 7 proved to be a better option owing to the ammonium-rich effluent (>220 mg/L) which was produced, which is on par with the nitrogen concentration of a Hoagland solution. The continuous carbon polishing of liquid digestate provides an efficient way of utilising organic fertilisers in hydroponic systems.
... After 3 h of inoculation, the seedlings were individually transferred into 50 mL pots filled with commercial substrate West Garden ® (West Garden Ltd.a, São Paulo, SP, Brazil) that was autoclaved for 40 min at 121 • C. The seedlings were incubated at 23 • C, 60% relative humidity, and 70 µmol m −2 s −1 light (12 h photoperiod) for 50 days. The seedlings were irrigated with 25% Hoagland's solution [69] every two days. ...
Gluconacetobacter diazotrophicus is a diazotrophic endophytic bacterium that promotes the growth and development of several plant species. However, the molecular mechanisms activated during plant response to this bacterium remain unclear. Here, we used the RNA-seq approach to understand better the effect of G. diazotrophicus PAL5 on the transcriptome of shoot and root tissues of Arabidopsis thaliana. G. diazotrophicus colonized A. thaliana roots and promoted growth, increasing leaf area and biomass. The transcriptomic analysis revealed several differentially expressed genes (DEGs) between inoculated and non-inoculated plants in the shoot and root tissues. A higher number of DEGs were up-regulated in roots compared to shoots. Genes up-regulated in both shoot and root tissues were associated with nitrogen metabolism, production of glucosinolates and flavonoids, receptor kinases, and transcription factors. In contrast, the main groups of down-regulated genes were associated with pathogenesis-related proteins and heat-shock proteins in both shoot and root tissues. Genes encoding enzymes involved in cell wall biogenesis and modification were down-regulated in shoots and up-regulated in roots. In contrast, genes associated with ROS detoxification were up-regulated in shoots and down-regulated in roots. These results highlight the fine-tuning of the transcriptional regulation of A. thaliana in response to colonization by G. diazotrophicus PAL5.
... Seeds of creeping bentgrass cultivar 'Penncross' germinated and grew in white quartz sands filled with ½ Hogland's nutrient solution (Hoagland and Arnon 1950) for 30 days. Mature plants with same sizes were removed carefully from quartz sands and then were suspended in Hogland's nutrient solution for hydroponic cultivation by using styrofoam floating boards on the rectangular container (25 cm in length, 15 cm in width, and 20 cm in height) for 7 days. ...
Main conclusion
γ-Aminobutyric acid alleviates acid-aluminum toxicity to roots associated with enhanced antioxidant metabolism as well as accumulation and transportation of citric and malic acids.
Abstract
Aluminum (Al) toxicity has become the main limiting factor for crop growth and development in acidic soils and is further being aggravated worldwide due to continuous industrial pollution. The current study was designed to examine effects of GABA priming on alleviating acid-Al toxicity in terms of root growth, antioxidant defense, citrate and malate metabolisms, and extensive metabolites remodeling in roots under acidic conditions. Thirty-seven-day-old creeping bentgrass (Agrostis stolonifera) plants were used as test materials. Roots priming with or without 0.5 mM GABA for 3 days were cultivated in standard nutrient solution for 15 days as control or subjected to nutrient solution containing 5 mM AlCl3·6H2O for 15 days as acid-Al stress treatment. Roots were sampled for determinations of root characteristics, physiological and biochemical parameters, and metabolomics. GABA priming significantly alleviated acid-Al-induced root growth inhibition and oxidative damage, despite it promoted the accumulation of Al in roots. Analysis of metabolomics showed that GABA priming significantly increased accumulations of organic acids, amino acids, carbohydrates, and other metabolites in roots under acid-Al stress. In addition, GABA priming also significantly up-regulated key genes related to accumulation and transportation of malic and citric acids in roots under acid-Al stress. GABA-regulated metabolites participated in tricarboxylic acid cycle, GABA shunt, antioxidant defense system, and lipid metabolism, which played positive roles in reactive oxygen species scavenging, energy conversion, osmotic adjustment, and Al ion chelation in roots.
... The seedlings were placed in the culturing room at Fujian Agriculture and Forestry University (26 • 5′N and 119 • 14′E) under natural light and temperature. The formula of the modified Hoagland nutrient solution was as follows: KNO 3 , 1 mM; Ca (NO 3 ) 2 , 1 mM; MgSO 4 , 0.5 mM; KH 2 PO 4 , 0.1 mM; H 3 BO 3 , 10 μM; MnCl 2 , 2 μM; ZnSO 4 , 2 μM; (NH 4 ) 6 Mo 7 O 24 , 0.065 μM; CuSO 4 , 0.5 μM and FeSO 4 -EDTA, 20 μM (Hoagland and Arnon, 1950). Seven weeks after transplantation, seedlings were supplied with nutrient solution with or without 1 mM AlCl 3 ⋅6 H 2 O (0 mM AlCl 3 ⋅6 H 2 O, -Al, control; or 1 mM AlCl 3 ⋅6 H 2 O, +Al) every other day until dripping (about 0.8 L nutrient solution for each pot). ...
Isoprenoid metabolism and its derivatives took part in photosynthesis, growth regulation, signal transduction, and plant defense to biotic and abiotic stresses. However, how aluminum (Al) stress affects the isoprenoid metabolism and whether isoprenoid metabolism plays a vital role in the Citrus plants in coping with Al stress remain unclear. In this study, we reported that Al-treatment-induced alternation in the volatilization rate of monoterpenes (α-pinene, β-pinene, limonene, α-terpinene, γ-terpinene and 3-carene) and isoprene were different between Citrus sinensis (Al-tolerant) and C. grandis (Al-sensitive) leaves. The Al-induced decrease of CO 2 assimilation, maximum quantum yield of primary PSII photochemistry (F v /F m), the lower contents of glucose and starch, and the lowered activities of enzymes involved in the mevalonic acid (MVA) pathway and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway might account for the different volatilization rate of isoprenoids. Furthermore, the altered transcript levels of genes related to isoprenoid precursors and/or derivatives metabolism , such as geranyl diphosphate (GPP) synthase (GPPS) in GPP biosynthesis, geranylgeranyl diphosphate synthase (GGPPS), chlorophyll synthase (CHS) and GGPP reductase (GGPPR) in chlorophyll biosynthesis, limonene synthase (LS) and α-pinene synthase (APS) in limonene and α-pinene synthesis, respectively, might be responsible for the different contents of corresponding products in C. grandis and C. sinensis. Our data suggested that isoprenoid metabolism was involved in Al tolerance response in Citrus, and the alternation of some branches of isoprenoid metabolism could confer different Al-tolerance to Citrus species.
... Plants were collected during their vegetative stage comprising rhizomes (10 cm long), roots, and about three leaves; these individuals were washed and selected for phytosanitary quality and uniformity of size. Then, they were taken to a greenhouse in the Department of Biology of the Federal University of Lavras, where they were grown in a nutrient solution of Hoagland and Arnon (1950) The clones were standardized in size (10 cm long rhizome, 3-5 leaves, and 10-15 roots) and transferred to plastic trays with a capacity of seven liters. The treatments consisted of six different concentrations of Pb: zero (control), 0.75; 1.5; 3.0 6.0, and 9.0 µM of Pb(NO 3 ) 2 . ...
Lead (Pb) can be deposited in aquatic environments that are especially subject to pollution due to wastewater and sewage disposal. This study aimed to evaluate the tolerance of Echinodorus grandiflorus (Cham. & Schltr.) Micheli to Pb and changes in growth, gas exchange, and leaf anatomy. Experiments were conducted with E. grandiflorus plants exposed to the following Pb concentrations in nutrient solution: [0; 0.75; 1.5; 3.0 and 9.0 μM Pb (NO 3)2] in a greenhouse for 60 days. At the end of the experiment, the lead concentration, growth, leaf gas exchange, and changes in leaf anatomy were evaluated. There was no mortality of E. grandiflorus plants, and they accumulated higher concentrations of Pb proportional to the concentration of the pollutant in the solution. Pb did not cause significant changes in growth, stomatal conductance, transpiration, and Ci/Ca rate but reduced the photosynthesis in E. grandiflorus. The leaf anatomy showed significant changes in the presence of Pb, reducing the epidermis and chlorophyll parenchyma. E. grandiflorus demonstrated tolerance to Pb, surviving and growing under contamination; however, it negatively modified its leaf anatomy and photosynthesis in the presence of the metal.
... Disease-free-viable soybean (Glycine max L.) seeds were surface sterilized with 70% ethanol for 1 min, seeds were washed properly using double distilled water, and then seeds were transferred to a germination tray for three days. Subsequently, 3 days later the soybean's small seedlings were transferred to micro-macro nutrient-containing traditional Hoagland solution [13]. The soybean seedlings were grown with the following combinations: 25 µM FeNaEDTA with all macro-micro element containing media (control); only 0.1 µM FeNaEDTA (−Fe); 0.1 µM FeNaEDTA +sodium nitroprusside (100 µM) as nitric oxide (NO) donor (-Fe+NO); and 100 µM SNP treatment (NO). ...
Iron (Fe)-shortage is a serious limitation in Strategy I dicot crops including soybean (Glycine max L.). Fe-deficiency causes chlorosis, growth retardation, low photosynthetic performance, and productivity. Nitric oxide (NO) is known to serve as a signalling molecule in plants, but its role in mitigating Fe-deficiency in soybeans is still vague. Therefore, the study aims to explore physiological and molecular mechanisms associated with Fe-acquisition and homeostasis is highly demandable. In this study, we found Fe-deficiency occurred leaf chlorosis, inhibiting photosynthetic performance and biomass yield in soybean. However, the exogenous supplementation of sodium nitroprusside, a donor of nitric oxide (NO) significantly restored these physiological attributes. The fluorescence intensity of NO indicates that NO-singling induced in response to Fe-deficiency, along with NO induces conversion of Fe3+ to Fe2+, which leads to Fe acquisition and homeostasis mechanism in Strategy I soybean plants. This study further suggests that NO up-regulates the expression candidate genes ZmIRT1, ZmFRO2, and ZmSultr1;3 related to Fe-acquisition and homeostasis in soybean plants. These findings might be useful to soybean breeders and farmers for coping with Fe-deficiency in Strategy I soybean and other grains crops.
... Alternatively, for hydroponic cultivation, the shoots were grown in plastic pots filled with high-density hydroton (0.8 cm in diameter). The pots from both soil and hydroponic cultivation systems were placed in plastic containers (35 cm width × 50 cm length ×15 cm height) containing reverse osmosis water and Hoagland solution [27], respectively ( Figure 1). These cultures were maintained indoors in a room without temperature control, with daytime ambient temperature ranging from 32 °C to 37 °C and nighttime temperature ranging from 28 °C to 32 °C. ...
Bacopa monnieri, a cognitive-enhancing herb crucial in health supplements, faces quality variations and contamination by toxic substances in conventional field cultivation, which hinders industrial use. Here, indoor cultivation of diploid (2x) and tetraploid (4x) B. monnieri using hydroponic and soil systems was studied. Soil cultivation promoted longer shoot lengths but resulted in lower biomass and chlorophyll contents compared to hydroponic cultivation. Conversely, soil cultivation significantly elevated total phenolics, total triterpenoids, bacoside A3, and bacopaside X contents in both lines, showing 1.7- to 3.3-fold increases over hydroponic cultivation. Furthermore, 4x plants grown in soil had higher bacopaside II and total bacoside contents than hydroponically grown plants, with 2- and 1.5-fold increases, respectively. Yet, no significant differences were observed in growth and pigment between 2x and 4x lines under the same system. Similarly, no significant differences in bioactive compound productions were found between 2x and 4x hydroponically grown plants. However, in soil, 4x plants exhibited higher total phenolic content, bacopaside II, and total bacoside contents compared to 2x plants. Interestingly, 2x plants grown in soil were the top performers for bacoside production per plant. These findings optimize cultivation practices to meet industry demands, warranting further research into large-scale production techniques.
... Water was sprinkled daily to keep the soil moist. Hoagland's nutrient solution was applied to ensure ample supply of nutrients (Hoagland and Arnon, 1950). At the end of the experiment (45 days after sowing), the early seedlings traits were recorded using standard scientific procedures as under: ...
... Plants were watered every week and fertilized with halfstrength Hoagland's solution (Hoagland & Arnon, 1950) every 2 wk at a rate of 200 ml per pot (from April to September 2008). One-year-old plants with similar aboveground biomass were selected and transferred into 3-gallon pots in March 2009 for subsequent experiments. ...
... Initially, 100 mL of distilled water per pot was applied for the first 7 days to maintain the required humidity for the seedlings. Distilled water was subsequently substituted with 200 mL of a nutrient solution for each pot [38], with a modification in the source of iron, alternating between Fe-EDTA and Fe-EDDHMA. The pH of the nutrient solution was monitored daily and kept within a range of 5.4 ± 0.3 by adjusting with 0.01 mol L −1 sodium hydroxide (NaOH) and/or hydrochloric acid (HCl). ...
Nitrogen (N) holds a prominent position in the metabolic system of plants, as it is a main constituent of amino acids, which are the basic building blocks of proteins and enzymes. Plants primarily absorb N in the form of ammonium (NH4+) and nitrate (NO3−). However, most plants exhibit severe toxicity symptoms when exposed to NH4+ as the sole N source. Addressing NH4+ stress requires effective strategies, and the use of silicon (Si) has shown promising results. However, there is a lack of underlying studies on the impact of NH4+ toxicity on C:N:P stoichiometric balance and the role of Si in these ratios. In this study, we explored the effects of varying NH4+ concentrations (1, 7.5, 15, 22.5, and 30 mmol L−1) on the C:N:P stoichiometry and yield of beetroot in hydroponic conditions. Additionally, we investigated whether the application of Si (2 mmol L−1) could mitigate the detrimental effects caused by toxic NH4+ levels. The experiment followed a randomized block design based on a 5 × 2 factorial scheme with four replicates. Results revealed that in the presence of Si, both [N] and [P] significantly increased in shoots and roots, peaking at 15 mmol L−1 of NH4+ in the nutrient solution. While shoot [C] remained stable, root [C] increased with NH4+ concentrations of 22.5 and 30 mmol L−1, respectively. Moreover, shoot and root [Si] increased with higher NH4+ levels in the nutrient solution. The findings underscored homeostatic instability under the highest NH4+ levels, particularly in plants cultivated without Si in the nutritive solution, leading to a reduction in both shoot and root dry matter production.
... The next step involved transferring them into hydroponic pots filled with Hoagland nutrient solution. The pots were then placed inside a greenhouse with the ideal conditions of a 14 h photoperiod and a day/night temperature of 28 °C (Hoagland and Arnon 1950). After the third true leaf emerged, the seedlings were exposed to sodium chloride (NaCl) 200 mM solutions to assess their response to salt stress. ...
Key message
The utilization of transcriptome analysis, functional validation, VIGS, and DAB techniques have provided evidence that GhiPLATZ17 and GhiPLATZ22 play a pivotal role in improving the salt tolerance of upland cotton.
Abstract
PLATZ (Plant AT-rich sequences and zinc-binding proteins) are known to be key regulators in plant growth, development, and response to salt stress. In this study, we comprehensively analyzed the PLATZ family in ten cotton species in response to salinity stress. Gossypium herbaceum boasts 25 distinct PLATZ genes, paralleled by 24 in G. raimondii, 25 in G. arboreum, 46 in G. hirsutum, 48 in G. barbadense, 43 in G. tomentosum, 67 in G. mustelinum, 60 in G. darwinii, 46 in G. ekmanianum, and a total of 53 PLATZ genes attributed to G. stephensii. The PLATZ gene family shed light on the hybridization and allopolyploidy events that occurred during the evolutionary history of allotetraploid cotton. Ka/Ks analysis suggested that the PLATZ gene family underwent intense purifying selection during cotton evolution. Analysis of synteny and gene collinearity revealed a complex pattern of segmental and dispersed duplication events to expand PLATZ genes in cotton. Cis-acting elements and gene expressions revealed that GhiPLATZ exhibited salt stress resistance. Transcriptome analysis, functional validation, virus-induced gene silencing (VIGS), and diaminobenzidine staining (DAB) demonstrated that GhiPLATZ17 and GhiPLATZ22 enhance salt tolerance in upland cotton. The study can potentially advance our understanding of identifying salt-resistant genes in cotton.
... Four weeks later, plants that successfully developed roots were replanted in 6 L pots that contained a mixture of brown soil:peat (Brill type 5, Kekkilä-BVB, Georgsdorf, Germany):perlite (Agrilit 3, Perlite espansa; Perlite Italiana, Milano, Italy) in 1:1:1 ration and 1/3 of volume of quartz sand (Lasselberger-Knauf, Ðurdevac, Croatia) was added in the mixture. Plants were grown in an experimental greenhouse (Schwarzman) under natural light, and during the vegetation period, the temperature ranged from 18 to 35 • C. Plants were irrigated with ¼ of Hoagland solution [22] once a week at the beginning of vegetation and once every two weeks when plants reached full growth. Hoagland solution was administered to provide all the macro-and micronutrients essential for grapevine growth and development. ...
The objective of this study was to investigate the response of the grapevine variety 'Tribidrag' to virus infection over two vegetation seasons. Virus-free plants were greenhouse cultivated and green grafted with five different virus inocula composed of grapevine leafroll-associated virus 3 (GLRaV-3) singly or in coinfection with other most economically important grapevine viruses. Changes in nutrient status and photosynthesis-related parameters, along with symptom development, were measured. Using the quantitative PCR method, the relative concentration of five selected Vitis genes was determined. Cluster analysis and ANOVA revealed the reduction in phosphorus concentration (P) and photosynthesis-related parameters in infected plants in both seasons, even in the absence of symptom expression, indicating P and assimilation rate (Photo (A)) as stable markers of virus infection. Plants infected with inoculum Y composed of five different viruses provoked major significant changes in the first season while, in the second, fewer changes were measured. The sucrose synthase 3 gene was upregulated in infected plants confirming disturbed sugar metabolism related to virus-induced stress. This study showed that virus-induced changes in 'Tribidrag' plants even in the absence of symptoms are dependent on plant age, as well as on the composition of virus inocula.
... To evaluate the expression of FT/TFL-like genes, hop plants of the NB genotype were grown in a Greenhouse of the plant Physiology sector of the Federal University of Lavras. The plants were produced according to Bauerle (2019), first, the cuttings were immersed in Hoagland solution (1/4) (Hoagland and Arnon 1950) for 2 weeks in growth chambers (16/8 light/obscure to 22 °C) until the cuttings developed roots. Second, the plants were transferred to 11 L pots with a mixture of 2:1 sand-soil and maintained in greenhouse conditions (28/20 °C day/night). ...
Main conclusion
The hop phenological cycle was described in subtropical condition of Brazil showing that flowering can happen at any time of year and this was related to developmental molecular pathways.
Abstract
Hops are traditionally produced in temperate regions, as it was believed that vernalization was necessary for flowering. Nevertheless, recent studies have revealed the potential for hops to flower in tropical and subtropical climates. In this work, we observed that hops in the subtropical climate of Minas Gerais, Brazil grow and flower multiple times throughout the year, independently of the season, contrasting with what happens in temperate regions. This could be due to the photoperiod consistently being inductive, with daylight hours below the described threshold (16.5 h critical). We observed that when the plants reached 7–9 nodes, the leaves began to transition from heart-shaped to trilobed-shaped, which could be indicative of the juvenile to adult transition. This could be related to the fact that the 5th node (in plants with 10 nodes) had the highest expression of miR156, while two miR172s increased in the 20th node (in plants with 25 nodes). Hop flowers appeared later, in the 25th or 28th nodes, and the expression of HlFT3 and HlFT5 was upregulated in plants between 15 and 20 nodes, while the expression of HlTFL3 was upregulated in plants with 20 nodes. These results indicate the role of axillary meristem age in regulating this process and suggest that the florigenic signal should be maintained until the hop plants bloom. In addition, it is possible that the expression of TFL is not sufficient to inhibit flowering in these conditions and promote branching. These findings suggest that the reproductive transition in hop under inductive photoperiodic conditions could occur in plants between 15 and 20 nodes. Our study sheds light on the intricate molecular mechanisms underlying hop floral development, paving the way for potential advancements in hop production on a global scale.
... Approximately, 75 saffron corms were planted in 20 cm deep trays with universal substrate (50%) and coconut fiber (50%) at a planting depth of about 10 cm. The plants were manually fertilized with Hoagland solution No. 2 every 10 days [34]. The samples of daughter corms, mother corm, and leaves ( Figure S1) were harvested on three different dates: when the corm was actively growing (17 January), before corm growth arrest (21 March), and shortly after corm growth arrest and once leaf senescence had been initiated (13 April). ...
The reproduction of Crocus sativus L., a sterile triploid plant, is carried out exclusively through corms, whose size determines the saffron yield. The development of daughter corms (DC) is supported by photoassimilates supplied by the leaves as well as by the mother corms (MC). While biomass partitioning during DC development is well studied, growth dynamics in terms of cell number and size, the involved meristems, as well as carbohydrate partition and allocation, are not yet fully understood. We conducted a comprehensive study into saffron corm growth dynamics at the macroscopic and microscopic levels. Variations in carbohydrate content and enzymatic activities related to sucrose metabolism in sources and sinks were measured. Two key meristems were identified. One is involved in vascular connections between DC and MC. The other is a thickening meristem responsible for DC enlargement. This research explains how the previously described phases of corm growth correlate with variations in cell division, enlargement dynamics, and carbohydrate partitioning among organs. Results also elucidated that the end of DC growth relates to a significant drop in MC root biomass, limiting the water supply for the DC growth, and establishing the onset of leaf wilting. The lack of starch accumulation in aged leaf cells is noteworthy, as is the accumulation of lipids. We hypothesize a signaling role of sugars in DC growth initiation, stop, and leaf aging. Finally, we established a predominant role of sucrose synthase as a sucrolytic enzyme in the maintenance of the high flux of carbon for starch synthesis in DC. Together, the obtained results pave the way for the definition of strategies leading to better control of saffron corm development.
To explain changes in plant growth, root architecture, and endogenous hormones of different root-type alfalfa to phosphorus (P) stress (non-stressed control, 1.00 mmol·L⁻¹ KH2PO4, versus P stress treatment, 0.01 mmol·L⁻¹ KH2PO4). We used the sand culture of rhizomatous-rooted Medicago sativa ‘Qingshui’ (QS), tap-rooted M. sativa ‘Longdong’ (LD), and creeping-rooted M. varia ‘Gongnong No. 4’ (GN) to study the performance with contrasting degrees of P tolerance. After 34 days of P stress treatment, values for plant height, leaf area, specific root length, specific surface area, zeatin (ZT) level, and P content were decreased in response to stress treatment. In contrast, the contents of indole-3-acetic acid (IAA), abscisic acid (ABA), and gibberellin (GA3), as well as the root/shoot ratio, total root length, taproot length, root angle, and the number of root tips and lateral roots, increased in the year and next year, respectively. The topological index and fractal dimension (FD) were small, while the fractal abundance (FA) and the average link length were large. The root branching patterns were dichotomous branching. The amplitude of this response of plant biomass, plant height, leaf length, leaf area, root/shoot ratio, total root length, number of root tips, root angle, specific surface area, and FD in GN of the year and next year was much smaller than those in LD and QS under low-P stress. From the point of view, GN was more tolerant than LD and QS under P condition.
Phosphorus (P) is a crucial macronutrient required for normal plant growth. Its effective uptake from the soil is a trait of agronomic importance. Natural variation in maize (339 accessions) root traits, namely root length and number of primary, seminal, and crown roots, root and shoot phosphate (Pi) contents, and root-to-shoot Pi translocation (root: shoot Pi) under normal (control, 40 ppm) and low phosphate (LP, 1 ppm) conditions, were used for genome-wide association studies (GWAS). The Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model of GWAS provided 23 single nucleotide polymorphisms (SNPs) and 12 relevant candidate genes putatively linked with root Pi, root: shoot Pi, and crown root number (CRN) under LP. The DNA-protein interaction analysis of Zm00001d002842, Zm00001d002837, Zm00001d002843 for root Pi, and Zm00001d044312, Zm00001d045550, Zm00001d025915, Zm00001d044313, Zm00001d051842 for root: shoot Pi, and Zm00001d031561, Zm00001d001803, and Zm00001d001804 for CRN showed the presence of potential binding sites of key transcription factors like MYB62, bZIP11, ARF4, ARF7, ARF10 and ARF16 known for induction/suppression of phosphate starvation response (PHR). The in-silico RNA-seq analysis revealed up or down-regulation of candidate genes along with key transcription factors of PHR, while Uniprot analysis provided genetic relatedness. Candidate genes that may play a role in P uptake and root-to-shoot Pi translocation under LP are proposed using common PHR signaling components like MYB62, ARF4, ARF7, ARF10, ARF16, and bZIP11 to induce changes in root growth in maize. Candidate genes may be used to improve low P tolerance in maize using the CRISPR strategy.
The issue of arsenic (As) contamination in the environment has become a critical concern, impacting both human health and ecological equilibrium. Addressing this challenge requires a comprehensive strategy encompassing water treatment technologies, regulatory measures for industrial effluents, and the implementation of sustainable agricultural practices. In this study, diverse strategies were explored to enhance As accumulation in the presence of Acinetobacter bouvetii while safeguarding the host from the toxic effects of arsenate exposure. The sunflower seedlings associated with A. bouvetii demonstrated a favorable relative growth rate (RGR) and net assimilation rate (NAR) even less than 100 ppm of As stress. Remarkably, the NAR and RGR of A. bouvetii-associated seedlings outperformed those of control seedlings cultivated without A. bouvetii in As-free conditions. Additionally, a markedly greater buildup of bio-transformed As was observed in A. bouvetii-associated seedlings (P = 0.05). An intriguing observation was the normal levels of reactive oxygen species (ROS) in A. bouvetii-associated seedlings, along with elevated activities of key enzymatic antioxidants like catalases (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), and peroxidases (POD), along with non-enzymatic antioxidants (phenols and flavonoids). This coordinated antioxidant defense system likely contributed to the improved survival and growth of the host plant species amidst As stress. A. bouvetii not only augmented the growth of the host plants but also facilitated the uptake of bio-transformed As in the contaminated medium. The rhizobacterium's modulation of various biochemical and physiological parameters indicates its role in ensuring the better survival and progression of the host plants under As stress.
Background: In wheat, the NAC family plays a crucial role in conferring cellular responses to different abiotic stresses, particularly drought. The functional NAM-B1 allele in durum wheat accelerates senescence, while its homologous genes contribute to improved water deficit stress tolerance. Therefore, the main objective of this study was to investigate the role of the NAM-B1 gene in durum wheat subjected to water deficit stress at two reproductive stages. Materials and Methods: Three Near-Isogenic Lines carrying a functional NAM-B1 allele and their recurrent parent, Langdon (LDN), were used in this study. The study assessed NILs and LDN performance under varied water conditions (well-watered, 60%, and 80% water deficit of pot capacity) during flag leaf and anthesis stages. The agronomic performance of the three NILs and LDN was assessed for 16 traits, including plant height, grain yield, and thousand kernel weight. Additionally, physiological measurements, including stomatal resistance, chlorophyll content (SPAD values), and chlorophyll fluorescence (Fv/Fm) were taken. Results: Significant genotypic effects were observed on seven agronomic traits, while 15 traits were influenced by the water stress treatment. The NILs exhibited accelerated maturity and a shorter grain-filling period, which were particularly pronounced under stress conditions. Severe water deficit resulted in reduced grain weight and thousand-grain weight in tested genotypes. Interestingly NILs carrying functional NAM-B1 showed taller plants and had higher tiller and spike numbers when compared to LND. Significant genotypic effects were observed for seven traits, and water stress treatments affected 15 traits. The NILs exhibited accelerated maturity and reduced grain weight under severe water deficit. Physiological measurements showed genotype and water-deficit differences, with NIL #504 displaying higher SPAD values, particularly under stress conditions, and a significant genotype X treatment effect was observed for stomatal resistance at the anthesis stage. Discussion: Limited treatment × genotype interactions for most traits highlight the complexity of drought tolerance in the tested lines, which might be attributed to its quantitative nature influenced by multiple genes. The study emphasizes the necessity for future research to explore the role of other NAM-related genes in response to water deficit stress and their interactive effects with the NAM-B1 gene at different growth stages in wheat plants subjected to diverse stress conditions. Conclusion: In conclusion, this study reveals pronounced genotypic effects, particularly in agronomic traits, such as maturation rate and grain filling period, under severe water deficit stress. Future studies are needed to understand the genetic mechanisms mediated by NAM-B1 genes in accelerating maturity in response to stress.
Nitrogen (N) is a macronutrient essential for plant growth and development; insufficient N availability has an extensive impact on the overall plant metabolism and productivity. Polyamines, short aliphatic amino-containing compounds naturally produced by living cells, have been widely reported to be beneficial for plant performance under several unfavorable conditions. In this work, the role of polyamine spermine (Spm) as a priming agent for wheat growing under N deficit was investigated. Wheat seeds were primed with 0.1 mM Spm for 3 h, germinated for 48 h, and then grown in N-sufficient or N-deficient media for 8 d. Spm treatment anticipated seed germination and, though priming with Spm did not result in any stimulatory effect on plants developed under an N-sufficient medium, under N limitation many of the studied traits improved compared with control plants. Under N deficit, wheat seedlings originated from Spm-primed seeds showed increased root length, developed the third leaf earlier, and maintained higher total N and protein contents and higher nitrate reductase (NR) and glutamine synthetase (GS) activities in their leaves, compared to control plants. Likewise, total amino acids increased in the roots of primed seedlings, and carbohydrates enhanced both in roots and leaves. Our findings indicate that seed priming with Spm promotes wheat germination and early seedling growth under N limitation, mainly by promoting root elongation and N allocation to the aerial part.
Biochar, a sustainable green technology product, is essential for promoting plant development and growth. Nano biochar emerges as a promising solution for environmental sustainability. Despite its potential, the intricate dynamics between plants and nano-biochar, particularly in finger millet (Eleusine coracana), remain largely unexplored, necessitating a deeper understanding of their interaction. This study investigates the effects of carbon nitride (C3N4) nano-biochar, derived from melamine, on finger millet. A screening setup was employed with varied concentrations of C3N4: 0 µM (control), 500 µM, 1000 µM, 1500 µM, and 2000 µM. Morphological parameters of plants includes root-shoot length, fresh and dry weights, were analysed to determine the optimal dosage. Results reveal that the most effective concentration of C3N4 for enhancing finger millet growth was found to be 1000 µM. Beyond this threshold, higher doses proved to be toxic, impeding plant growth and development. This research sheds light on the unexplored relationship between nano-biochar and plant physiology, offering insights crucial for sustainable agricultural practices.
As population growth accelerates, agriculture’s significance in our lives remains paramount. However, this surge in population has led to land degradation and increased food scarcity. The impact of silicon (Si) on plants has garnered significant attention in agricultural research. This study was aimed at examining the impact of Si on barley (Hordeum vulgare) plants by administering varying concentrations (5µM, 10µM, 20µM, 50µM, 100µM, 200µM, 500µM, 1000µM) and assessing their effects on plant growth parameters, particularly root and shoot lengths, and root fresh weight. Our study employed a controlled experimental setup to observe how barley plants respond to varying concentrations of Si. The data indicates that Si concentrations up to 10µM offer advantageous effects on barley compared to the control group, suggesting its potential in bolstering agricultural productivity. Similarly, concentrations of 20µM, 50µM, and 100µM were identified as safe for plant growth, opening avenues for their agricultural utilization. However, concentrations of 500µM and 1000µM resulted in complete inhibition of plant growth, emphasizing the necessity for cautious Si application in agriculture to prevent adverse impacts on crop yields. These findings underscore the importance of fine-tuning Si concentrations in agricultural practices to optimize benefits while mitigating potential risks to plants.
Plants require nitrogen (N) in various forms to facilitate essential physiological functions. Nitrate (NO3⁻) is one of the most readily absorbed N forms by plants and is preferred in well-aerated soils because it can be easily transported within the plant. Ammonium (NH4⁺), on the other hand, is utilized especially in waterlogged or acidic soils, where it is directly absorbed by the roots and incorporated into amino acids. Urea (CH4N2O) is another significant N source found in many fertilizers; it is transformed into NH4⁺ and nitrate in the soil through microbial processes. These diverse forms of N are crucial for supporting photosynthesis, protein synthesis, and energy production in plants. The escalating use of ammonium sulphate (NH4)2SO4) as a N source in agriculture prompts a thorough examination of its impact on crop health and productivity. This study aimed to investigate the NH4⁺ toxicity on rice (Oryza sativa) plants by administering various dosages (0 mM, 5 mM, 7 mM, 10 mM, 12 mM, and 15 mM) and assessing their effects on plant growth parameters, particularly root-shoot lengths, root-shoot fresh biomass along with dry weight. Our research utilized a controlled experimental setup to monitor the growth responses of rice plants to these NH4⁺ concentrations. Results indicated a clear threshold of tolerance, with adverse effects becoming significant at concentrations starting from 7 mM. At this concentration and higher, there was a noticeable decline in root-shoot lengths, root-shoot biomass and dry biomass, marking the onset of toxicity symptoms in rice plants. These findings suggest a critical need for regulated application of (NH4)2SO4 in rice cultivation to avoid detrimental effects on plant health and yield. The study underscores the importance of establishing safe usage guidelines for (NH4)2SO4 in agriculture, ensuring sustainable farming practices while maintaining crop productivity.
Boron (B) is an essential microelement in plant growth and development. However, the molecular mechanisms underlying B uptake and translocation in Brassica napus are poorly understood. Herein, we identified a low‐B (LB)‐inducible gene, namely BnaC4.BOR2 , with high transcriptional activity in root tips, stele cells, leaves, and floral organs. The green fluorescence protein labelled BnaC4.BOR2 protein was localised to the plasma membrane to demonstrate the B efflux activity in yeast and Arabidopsis . BnaC4.BOR2 knockout considerably reduced B concentration in the root and xylem sap, and altered B distribution in different organs at low B supply, exacerbating B sensitivity at the vegetative and reproductive stages. Additionally, the grafting experiment showed that BnaC4.BOR2 expression in the roots contributed more to B deficiency adaptability than that in the shoots. The pot experiments with LB‐soil revealed B concentration in leaves and siliques of BnaC4.BOR2 mutants were markedly reduced, showing an obvious B‐deficient phenotype of ‘flowering without seed setting’ and a considerable reduction in seed yield in B‐deficient soil. Altogether, the findings of this study highlight the crucial role of BnaC4.BOR2 in B uptake and translocation during B. napus growth and seed yield under LB conditions.
Soil salinity poses a substantial threat to agricultural productivity, resulting in far-reaching consequences. Greensynthesized lignin nanoparticles (LNPs) have emerged as significant biopolymers which effectively promote
sustainable crop production and enhance abiotic stress tolerance. However, the defensive role and underlying
mechanisms of LNPs against salt stress in Zea mays remain unexplored. The present study aims to elucidate two
aspects: firstly, the synthesis of lignin nanoparticles from alkali lignin, which were characterized using Field
Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Fourier Infrared
Spectroscopy (FT-IR) and Energy Dispersive X-Ray Spectroscopy (EDX). The results confirmed the purity and morphology of LNPs. Secondly, the utilization of LNPs (200 mg/L) in nano priming to alleviate the adverse
effects of NaCl (150 mM) on Zea mays seedlings. LNPs significantly reduced the accumulation of Na+ (17/21%)
and MDA levels (21/28%) in shoots/roots while increased lignin absorption (30/31%), resulting in improved
photosynthetic performance and plant growth. Moreover, LNPs substantially improved plant biomass, antioxidant enzymatic activities and upregulated the expression of salt-tolerant genes (ZmNHX3 (1.52 & 2.81 FC), CBL
(2.83 & 3.28 FC), ZmHKT1 (2.09 & 4.87 FC) and MAPK1 (3.50 & 2.39 FC) in both shoot and root tissues.
Additionally, SEM and TEM observations of plant tissues confirmed the pivotal role of LNPs in mitigating NaClinduced stress by reducing damages to guard cells, stomata and ultra-cellular structures. Overall, our findings
highlight the efficacy of LNPs as a practical and cost-effective approach to alleviate NaCl-induced stress in Zea
mays plants. These results offer a sustainable agri-environmental strategy for mitigating salt toxicity and
enhancing crop production in saline environments.
The objective of this work was to evaluate the effect of the use of the Murashige & Skook (MS) and Linsmaer & Skoog (LS) media and of filter caps on culture flasks on the morphological and physiological characteristics of basil cultivars in vitro, as well as to determine the composition of the essential oil of plants acclimatized in pots. For the evaluation of the cultivation media, cultivars Anise, Cinnamon, Grecco a Palla, and Italian Large Leaf were used. The Anise, Cinnamon, Italian Large Leaf, and Maria Bonita cultivars were used for the evaluation of the use of filter caps. The composition of the essential oils of cultivars Anise, Cinnamon, and Italian Large Leaf was also evaluated. The basil seedlings showed a higher aerial-part dry mass and a lower hyperhydricity rate when grown in the MS medium. The flasks without filter caps produced seedlings with lower contamination rates. When acclimatized in pots, cultivars Limoncino and Anise presented the tallest plants with the largest crown diameters. In the composition of essential oils, methyl cinnamate and linalool stood out in cultivar Cinnamon, methyl chavicol in Anise, and linalool in Italian Large Leaf. In the in vitro cultivation, the evaluated cultivars present a higher aerial-part production in the MS medium and a lower contamination without the use of filters, whereas, in the pots, the composition of essential oils varies according to the cultivar.
Ilıman iklim meyve türlerinden olan badem (Prunus dulcis) yetiştiriciliğinde ilkbahar geç donları üretimi kısıtlayan ve türün yetiştirilme ekolojisini belirleyen stres koşullarının başında gelmektedir. Bitkilerde soğuğa tolerans konusundaki seleksiyonlar çoğunlukla fenolojik gözlemlere dayandırılmaktadır. Türe ait çeşitlerde genetik varyasyon düşük olmakla birlikte toleransta da farklılıklar görülmekte, bunun temelinde ise bireyler arası genetik mekanizma farklılığı rol oynamaktadır. Bu çalışmada, çiçeklenme süresi bakımından farklılık gösteren yabani badem türleri (Amygdalus arabica, A.orientalis), yerel ve ticari badem çeşitleri de dahil olmak üzere 16 badem genotipinde, soğuğa toleransta anahtar düzenleyici olduğu düşünülen CBF genlerinin (PdCBF1, PdCBF2) real-time PCR ile gen ifade analizleri gerçekleştirilmiş ve soğuğa toleranslılıkla ilgili genotipler arası karşılaştırmalar yapılmıştır. Analizler sonucunda, hem PdCBF1 hem de PdCBF2 geninde en fazla gen ifade artışı Bertina çeşidinde (sırası ile 99.63 kat ve 78.62 kat) olurken, en fazla gen ifade azalışı ise Ferraduel çeşidinde (sırası ile -59.30 ve -77.70 kat) tespit edilmiştir. Diğer yandan, Gülcan 2, Ferraduel ve Primorski çeşitlerinde ise her iki gen bakımından da gen ifade azalışı gözlemlenmiş olup, bu genotiplerin soğuğa toleranslı olabilecekleri düşünülmektedir. Çalışma bulgularının bademde soğuğa tolerans ile ilgili yapılacak gen düzeyindeki diğer çalışmalara yardımcı olacağı düşünülmektedir.
Rapeseed (Brassica napus L.) is a major oilseed crop with high boron (B) requirements. In hydroponic cultivation, B uptake is highly responsive to the media conditions (e.g., pH). Different N sources, such as NH4⁺ and NO3⁻, directly affect the media pH. To date, the underlying mechanisms, the role of the buffering at constant N-sources by separating the effects of pH and/or sources of N-form, for the uptake of B remain indistinct under hydroponic cultivation, particularly in rapeseed. Two identical experiments were conducted using (NH4)2SO4 and Ca(NO3)2 as sole N-sources each set were subjected to four treatments viz. non-buffered, buffered pH 5.0, 6.0, and 7.0 at low (1 µM) and high (100 µM) B for 5 days. The novelty of this study demonstrates that NH4⁺-fed plants prefer buffered pH (6 and 7) for promoting higher plant growth, which was in line with the B concentration, while NO3⁻-fed plants were not influenced. These aforesaid findings were further supported by the upregulation of BnaNIP5;1 and BnaBOR1;2 in the root and higher expression of BnaNIP5;1 in shoots with buffered pH in NH4⁺-fed plants. According to our findings, in NH4⁺-based buffering, B transport channel protein BnaNIP5;1 (through diffusion) facilitated B uptake and distribution from root to shoot while BnaBOR1;2 mediated active uptake of B was in root under low supply of B. In a nutshell, pH buffering in hydroponics is very important in NH4⁺-based but not in NO3⁻-based nutrition for the uptake of boron and growth of the rapeseed plants.
Boosting plant immunity by priming agents can lower agrochemical dependency in plant production. Levan and levan-derived oligosaccharides (LOS) act as priming agents against biotic stress in several crops. Additionally, beneficial microbes can promote plant growth and protect against fungal diseases. This study assessed possible synergistic effects caused by levan, LOS and five levan- and LOS-metabolizing Bacillaceae (Bacillus and Priestia) strains in tomato and wheat. Leaf and seed defense priming assays were conducted in non-soil (semi-sterile substrate) and soil-based systems, focusing on tomato-Botrytis cinerea and wheat-Magnaporthe oryzae Triticum (MoT) pathosystems. In the non-soil system, seed defense priming with levan, the strains (especially Bacillus velezensis GA1), or their combination significantly promoted tomato growth and protection against B. cinerea. While no growth stimulatory effects were observed for wheat, disease protective effects were also observed in the wheat-MoT pathosystem. When grown in soil and subjected to leaf defense priming, tomato plants co-applied with levan and the bacterial strains showed increased resistance to B. cinerea compared with plants treated with levan or single strains, and these effects were synergistic in some cases. For seed defense priming in soil, more synergistic effects on disease tolerance were observed in a non-fertilized soil as compared to a fertilized soil, suggesting that potential prebiotic effects of levan are more prominent in poor soils. The potential of using combinations of Bacilliaceae and levan in sustainable agriculture is discussed.
Salinity, which is one of the major abiotic stresses, prevails in mostly arid and semiarid areas that is nearly 20% of the world’s cultivated area. Excessive amounts of salt around the plant root zone are detrimental to vegetative growth and economic yield. Today salinization is still severely expanding and posing a great threat to the development of sustainable agriculture. Although eggplant (Solanum melongena L.) is considered moderately sensitive, soil salinity mitigates strictly the growth and yield. Eggplant has significant crop wild relatives (CWRs) which are thought to be more tolerant to abiotic stresses and it is substantial to exploit their potential against salinity in hybrid breeding studies. It has previously been proven that Solanum incanum L. has tolerance to salinity stress. This study aimed to improve salinity-tolerant pure eggplant lines. Therefore, the acquired F2 population from interspecific hybridization between the pure line (BATEM-TDC47) with distinctive features from BATEM eggplant gene pool and S. incanum L., were subjected to salinity stress at 150 mM NaCl level with its parents and F1 plants. On the 12th day after the last salt treatment, the plants were evaluated using a 0-5 visual scale. Among the 256 stressed plants, 50 F2 individuals were determined to be salt tolerant. Additionally, some of their morphological and physiological features, such as shoot length, stem diameter, number of leaves, anthocyanin presence, prickliness, malondialdehyde (MDA), and proline levels, were studied and compared to the controls of their parent and F1 plants. Results showed that shoot length and stem diameter decreased dramatically under salt stress. According to the analysis, the average MDA and proline levels of the F2 population were identified as 10.9 µ mol g-1 FW and 8.4 µ mol g-1 FW, respectively. The distinguished 50 F2 plants that showed salinity tolerance were transferred to the greenhouse and self-pollinated to produce the F3 generation.
Introduction
Toxicity due to excess soil iron (Fe) is a significant concern for rice cultivation in lowland areas with acidic soils. Toxic levels of Fe adversely affect plant growth by disrupting the absorption of essential macronutrients, and by causing cellular damage. To understand the responses to excess Fe, particularly on seedling root system, this study evaluated rice genotypes under varying Fe levels.
Methods
Sixteen diverse rice genotypes were hydroponically screened under induced Fe levels, ranging from normal to excess. Morphological and root system characteristics were observed. The onset of leaf bronzing was monitored to identify the toxic response to the excess Fe. Additionally, agronomic and root characteristics were measured to classify genotypes into tolerant and sensitive categories by computing a response stability index.
Results
Our results revealed that 460 ppm of Fe in the nutrient solution served as a critical threshold for screening genotypes during the seedling stage. Fe toxicity significantly affected root system traits, emphasizing the consequential impact on aerial biomass and nutrient deprivation. To classify genotypes into tolerant and sensitive categories, leaf bronzing score was used as a major indicator of Fe stress. However, the response stability index provided a robust basis for classification for the growth performance. Apart from the established tolerant varieties, we could identify a previously unrecognized tolerant variety, ILS 12–5 in this study. Some of the popular mega varieties, including BPT 5204 and Pusa 44, were found to be highly sensitive.
Discussion
Our findings suggest that root system damage, particularly in root length, surface area, and root volume, is the key factor contributing to the sensitivity responses under Fe toxicity. Tolerant genotypes were found to retain more healthy roots than the sensitive ones. Fe exclusion, by reducing Fe ²⁺ uptake, may be a major mechanism for tolerance among these genotypes. Further field evaluations are necessary to confirm the behavior of identified tolerant and sensitive lines under natural conditions. Insights from the study provide potential scope for enhancement of tolerance through breeding programs as well as throw light on the role root system in conferring tolerance.
Defense priming is a strategy that enables plants to react faster, minimizing the damage suffered and allowing
them to survive stress. Here, we investigated the physiological and morphological changes underpinning stress
memory and adaptive capacity in soybean plants subjected to water deficit and/or waterlogging at two developmental stages. Our experiment was carried out in a greenhouse with seven treatments and four replicates:
control (non-stressed plants), water deficit at R2; water deficit both at V4 and R2; water deficit in V4 and
waterlogging in R2; waterlogging in R2; waterlogging in both V4 and R2; and waterlogging at V4 and water
deficit at R2. Samples for biometric analyses, measurements of xylem water potential, leaf gas exchange, chlorophyll a fluorescence, and quantification of photosynthetic pigments were harvested on the last day of stress
(R2) and four days after recovery. Primed and cross-primed plants showed improvements in leaf water potential
and relative water content due to the greater water use efficiency. Together with the osmotic effects, these plants
developed greater protection of the photosynthetic apparatus, showing a superior capacity to transfer energy
between photosystems as well as to dissipate photon excess as heat. They also showed a greater ability to recover
after periods of stress and maintained carotenoid levels. This study adds another piece of evidence that soybean
plants have stress memory, important to maintain high productivity under a global climate change.
Plants generate reactive oxygen species (ROS) during different metabolic processes, which play an essential role in coordinating growth and response. ROS levels are sensitive to environmental stresses and are often used as a marker for stress in plants. While various methods can detect ROS changes, histochemical staining with nitroblue tetrazolium (NBT) and 3,3′-diaminobenzidine (DAB) is a popular method, though it has faced criticism. This staining method is advantageous as it enables both the quantification and localization of ROS and the identification of the enzymatic origin of ROS in plants, cellular compartments, or gels. In this protocol, we describe the use of NBT and DAP staining to detect ROS generation under different stresses such as nitrogen starvation, wounding, or UV-C. Additionally, we describe the use of NBT staining for detecting enzymatic generation of ROS in native and native SDS PAGE gels. Our protocol also outlines the separation and comparison of the origin of ROS generated by xanthine dehydrogenase1 (XDH1) using different substrates.
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