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The root system of the tomato plants under the three cultivation conditions tested 60 dag. (A) Optimal water regimen, root length about 100 cm; (B) water scarcity regimen, root length about 80 cm; (C) water scarcity regimen coupled with paramylon root treatment, root length about 10 cm.
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Tomatoes, the most cultivated vegetables worldwide, require large amounts of water and are adversely affected by water stress. Solanum lycopersicum L., cv. Micro-Tom was used to assess the effects of β-(1,3)-glucan (paramylon) purified from the microalga Euglena gracilis on drought resistance and fruit quality profile. Plants were grown in an aerop...
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Context 1
... the optimal water regimen (Figure 2A), plants showed a normal compact growth habit with short internodes, fully expanded leaves, and regular fruit size typical of the determinate growth of Micro-Tom. The root system was fully developed with extremely long roots and plenty lateral roots, indicating a superior growth with respect to the plants under the other cultivation conditions ( Figure 3A). Drought stressed plants ( Figure 2B) showed wilting symptoms, with yellowing and rolling of the lower leaves, as well as a reduced fruit size. ...
Context 2
... stressed plants ( Figure 2B) showed wilting symptoms, with yellowing and rolling of the lower leaves, as well as a reduced fruit size. The root system appeared reduced in density and length ( Figure 3B). Stressed plants with paramylon root treatment ( Figure 2C) did not show any wilting; the growth habit was quite compact, the internode length was greater with respect to plants grown under optimal water regimen, and the fruit sizes were comparable. ...
Context 3
... plants with paramylon root treatment ( Figure 2C) did not show any wilting; the growth habit was quite compact, the internode length was greater with respect to plants grown under optimal water regimen, and the fruit sizes were comparable. The root system showed a dramatic reduction of both density and length, coupled with an increase of the lateral rootlets ( Figure 3C). Figures 4 and 5 show the variations of the main eco-physiological parameters, monitored to highlight the effect of the paramylon root treatment during the life cycle of the plants. ...
Citations
... Scartazza et al. (2017) demonstrated the dose-dependent effects of E. gracilis paramylon on xylem sap hormonal content, photosynthetic performance, and dehydration tolerance of tomatos (Solanum lycopersicum L.). Barsanti et al. (2019) investigated the impact of purified paramylon from E. gracilis on drought resistance and tomato quality, confirming the biostimulant activity of paramylon in enhancing plant adaptation capacity to abiotic stress. Recently, Foglio et al. (2022) showcased the biostimulant effects of Euglena sp. ...
Microalgae are increasingly recognized as a valuable resource for bolstering sustainability in agriculture. However, current research and patents primarily focus on Chlorella spp., Scenedesmus spp., and Spirulina spp., thus leaving the vast diversity of microalgae relatively unexplored for agricultural applications. Euglena gracilis (Euglenophyta) is a microalga renowned for its resilience to diverse environmental stressors and capability to produce a variety of bioactive metabolites. This study investigated the potential of cultivating E. gracilis in piggery wastewater for nutrient recycling and as a source of beneficial biomolecules, particularly for biostimulant use. Utilizing raw wastewater diluted to 25% (P25) and pre-treated wastewater with photo-Fenton (PF), the research found that E. gracilis exhibited elevated cell density, biomass concentration, and overall cell health in both wastewaters compared to a synthetic medium (BG11-NPK). This was due to its efficient removal of nutrients, especially ammoniacal-nitrogen and phosphate, resulting in a biomass rich in polyunsaturated fatty acids, amino acids, and paramylon content. The whole-cell biomass significantly enhanced the germination index of lettuce and tomato seeds compared to the water control. Additionally, it promoted cell expansion and root formation in cucumber cotyledons, exhibiting similarities to phytohormones such as gibberellin, cytokinin, and auxin. Furthermore, it is suggested that E. gracilis biomass contains molecules related to resistance to environmental stresses, particularly in tomatoes, given the enhancement in the seedling vigor index. E. gracilis exhibited remarkable adaptability to piggery wastewater, recycling nutrients and yielding biomass rich in bioactive molecules with potential as plant biostimulants. These findings significantly contribute to understanding E. gracilis's potential applications in agriculture and developing a circular bioeconomy.
... Recent research focuses and dehydration tolerance of tomatoes (Solanum lycopersicum L.). Barsanti et al. (2019) investigated the impact of puri ed paramylon from E. gracilis on drought resistance and tomato quality, con rming the biostimulant activity of paramylon in enhancing plant adaptation capacity to abiotic stress. Recently, Foglio et al. (2022) showcased the biostimulant effects of Euglena sp. ...
Microalgae are increasingly recognized as a valuable resource for bolstering sustainability in agriculture. Yet, current research often overlooks the diversity of microalgae species. Euglena gracilis (Euglenophyta) is a microalga renowned for its resilience to diverse environmental stressors and capability to produce a variety of bioactive metabolites. This study investigated the potential of cultivating E. gracilis in piggery wastewater for nutrient recycling and as a source of beneficial biomolecules, particularly for biostimulant use. Utilizing raw wastewater diluted to 25% (P25) and pre-treated wastewater with photo-Fenton (PF), the research found that E. gracilis exhibited elevated cell density, biomass concentration, and overall cell health in both wastewaters compared to a synthetic medium (BG11-NPK). This was due to its efficient removal of nutrients, especially ammoniacal-nitrogen and phosphate, resulting in a biomass rich in polyunsaturated fatty acids, amino acids, and paramylon content. The whole-cell biomass significantly enhanced the germination index of lettuce and tomato seeds compared to the water control. Additionally, it promoted cell expansion and root formation in cucumber cotyledons, exhibiting similarities to phytohormones such as gibberellin, cytokinin, and auxin. Furthermore, it is suggested that E. gracilis biomass contains molecules related to resistance to environmental stresses, particularly in tomatoes, given the enhancement in the seedling vigor index. E. gracilis exhibited remarkable adaptability to piggery wastewater, recycling nutrients and yielding biomass rich in bioactive molecules with potential as plant biostimulants. These findings significantly contribute to understanding E. gracilis 's potential applications in agriculture and developing a circular bioeconomy.
... Tomato (S. lycopersicum L.) requires large amounts of water. Consequently, it is negatively affected by water deficits, especially during the reproductive phase, where photosynthesis is limited, with an intensification of floral abortion and, as a result, a reduction in yield [22,23]. This vegetable is the most cultivated in the world and is one of the most nutritionally and economically important crops [24]. ...
A water deficit can negatively impact fruit yield and quality, affecting critical physiological processes. Strategies to mitigate water deficits are crucial to global food security. Iodine (I) may increase the efficiency of the antioxidant system of plants, but its role against water deficits is poorly understood. This study aimed to evaluate the effectiveness of I in attenuating water deficits and improving fruit quality, investigating whether metabolic responses are derived from a “priming effect” or stress relief during water deficits. Tomato plants were exposed to different concentrations of potassium iodide (KI) via a nutrient solution and subjected to a water deficit. A water deficit in tomatoes without KI reduced their yield by 98%. However, a concentration of 100 μM of KI increased the yield under a water deficit by 28%. This condition is correlated with increased antioxidant activity, photosynthetic efficiency improvement, and malondialdehyde reduction. In addition, the concentration of 100 μM of KI promoted better fruit quality through antioxidant capacity and a decline in the maturation index. Therefore, KI can be an alternative for attenuating water deficits in tomatoes, inducing positive responses during the water deficit period while at the same time improving fruit quality.
... Among polysaccharides, β-glucans are the most important, and are present inside the algae as storage compounds or wall components. β-glucans have a potent immunomodulating activity [10][11][12][13][14]. Their action is mediated through receptors such as Dectin-1 (a C-type lectin receptor), Toll-like receptors, complement receptor 3, scavenger receptor and lactosylceramide. ...
Algae (macro- and micro-algae) can be defined as light-driven cell factories that synthesize bioactive compounds consisting of primary metabolites (i [...]
... Drought is the most serious environmental stressor in agriculture worldwide, with more than half of the world's arable land forecast to be severely salinized by 2050. (Barsanti et al. 2019). It is a common, repeating characteristic of climate that can be seen in almost all climate zones. ...
Biostimulants are products that reduce fertiliser requirements while also stimulating plant growth and protecting crops from abiotic stress by increasing tolerance. Biostimulants such as algal or other plant extracts, protein hydrolysates, humic and fulvic acids, and other enhanced combinations have been shown to promote further growth and stress adaptability. These outcomes consist of higher yield, enhanced nutrient absorption and utilization, increased photosynthetic activity, and tolerance to both biotic and abiotic stressors. While most biostimulants have a variety of effects on plant growth, this chapter concentrates on bioprotective effects against abiotic stress. Biostimulants have the potential to make agriculture more sustainable and resilient, as well as provide an alternative to synthetic protectants, which have proven increasingly unpopular with consumers. In this regard, this chapter seeks to discuss the specific function of biostimulants that have defensive effects against abiotic stress, but also highlights the urgent need to investigate the underlying processes that cause these benefits.
... The great increase of physical-chemical and quality parameters such as the antioxidant compounds (Vitamin A/C/E, lycopene, β-carotene, and phenols) together with the increase of carbohydrates (glucose, fructose, and sucrose) in the fruits of paramylontreated plants improved their nutritional value and sensory quality. Moreover, the higher dry matter content (i.e., lower moisture) allowed a better post-harvest storage capability, extending the commercial period and increasing the commercial product value [51,52]. ...
Many algae synthesize compounds that have exceptional properties of nutraceutical, pharmacological, and biomedical interest. Pigments, fatty acids, phenols, and polysaccharides are among the main compounds investigated so far. Polysaccharides are the most exploited compounds, widely used in pharmaceutical, food, and chemical industries, which are at present entering into more advanced applications by gaining importance, from a therapeutic point of view, as antioxidant, antimicrobial, antitumor, and immunomodulatory agents. Establishing algae as an alternative supplement would complement the sustainable and environmental requirements in the framework of human health and well-being. This review focuses on the proprieties and uses of the main micro- and macroalgae metabolites, describing their potential for application in the different industrial sectors, from food/feed to chemical and pharmacological. Further, current technologies involved in bioactive molecule extraction strategies are documented.
... These findings indicate a response that depended on the biostimulant as well as on the water status of plants, since carotenoids are considered a part of the non-enzymatic protective mechanism of plants [7]. According to literature reports, biostimulants consisting of protein hydrolysates, carbohydrates (paramylon) or seaweed extracts may increase the carotenoid content under optimal or unfavorable conditions [64,65], whereas other reports did not record any effects on the carotenoid content of organically grown tomato fruit after the application of various biostimulants obtained from food by-products [15] or based on humic substances [16]. Therefore, apart from the water status of plants (e.g., irrigation regime), there seems to be a biostimulant-specific response of carotenoid content. ...
The aim of the present study was to evaluate the effects of three biostimulant products (Nomoren (N), Twin Antistress (TW), x-Stress (XS) and control treatment (C: no biostimulants added)) on the nutritional value, chemical composition and bioactive properties of greenhouse tomato fruit grown under full (W+: 100% of field capacity) and deficit irrigation (W-: 70% of field capacity) conditions. Fat content was the highest for the fully irrigated plants that received no bi-ostimulants (CW+), while proteins and carbohydrates and energetic value were the highest in the XSW+ treatment. The content of the main detected sugars (fructose, glucose and trehalose) varied depending on the irrigation and biostimulant treatment. The highest amounts of individual and total organic acids and tocopherols were recorded in fully irrigated plants treated with Twin Antis-tress (TW), whereas the lowest overall values were observed under deficit irrigation for plants that received the XS treatment. The most abundant fatty acids were palmitic (27.5-36.0%) and linoleic acid (27.4-35.4%), followed by oleic (9.2-21.2%), linolenic (5.4-13.1%) and stearic acid (5.3-6.8%). Moreover, the highest values of β-carotene and lycopene were recorded for the CW-and NW+ treatments , respectively. The TWW+ showed the highest antioxidant activity for both assays tested (TBARS and OxHLIA). Most of the tested extracts showed lower antibacterial activity against the tested bacteria compared to the positive controls. On the other hand, CW+, XSW+ and XSW-treatments showed higher antifungal activity (MIC values) than positive controls. In conclusion, each biostimulant product had a different effect on the determined characteristics depending on the level of irrigation. Therefore, more research is needed to better identify the mechanisms of action and the physiological processes, after which the tested biostimulants may be used to standardize the application of such products in tomato cultivation.
... Increased antioxidants (carotenoids, vitamins and phenolic acids) and soluble carbohydrates (glucose, fructose, and sucrose) in fruits;Increase endogenous indole-3-acetic acid (auxin), trans-zeatin (cytokinin), and jasmonic acid [191,192] SWEs (A. nodosum) Drought Soybean ...
Demand for organically grown food crops is rising substantially annually owing to their contributions to human health. However, organic farm production is still generally lower compared to conventional farming. Nutrient availability, content consistency, uptake, assimilation, and crop responses to various stresses were reported as critical yield-limiting factors in many organic farming systems. In recent years, plant biostimulants (BSs) have gained much interest from researchers and growers, and with the objective of integrating these products to enhance nutrient use efficiency (NUE), crop performance, and delivering better stress resilience in organic-related farming. This review gave an overview of direct and indirect mechanisms of microbial and non-microbial BSs in enhancing plant nutrient uptake, physiological status, productivity, resilience to various stressors, and soil-microbe-plant interactions. BSs offer a promising, innovative and sustainable strategy to supplement and replace agrochemicals in the near future. With greater mechanistic clarity, designing purposeful combinations of microbial and non-microbial BSs that would interact synergistically and deliver desired outcomes in terms of acceptable yield and high-quality products sustainably will be pivotal. Understanding these mechanisms will improve the next generation of novel and well-characterized BSs, combining microbial and non-microbial BSs strategically with specific desired synergistic bio-stimulatory action, to deliver enhanced plant growth, yield, quality, and resilience consistently in organic-related cultivation.
... Three concentrations of Fe-EDTA, such as 100 μM, 150 μM, and 200 μM were freshly prepared and sprayed once a week, whereas distilled water was used as the control. The range of Fe concentrations was selected based on the optimal concentration along with a relatively low and a high level (Barsanti et al. 2019). Fe-EDTA was selected as the source of Fe as chelates increase the solubility of Fe, and the Fe-chelated fertilizer is a reliable and abundant source of bivalent Fe due to its high stability and release (Hamid et al. 2015). ...
Photoperiod and micronutrient iron (Fe) are critical for plant growth and development. However, the interactive effects of Fe nutrition and photoperiod on tomato plant growth and fruit quality remain elusive. In this study, the tomato genotype 'Micro-tom' was used to explore the influence of different concentrations of exogenous Fe (0, 100, 150, 200 μM Fe-EDTA) under two photoperiods (12 h/12 h and 16 h/8 h) on tomato plant growth, photosynthetic characteristics, and fruit quality parameters. The results show that compared with the 12 h/12 h photoperiod, the vegetative growth, and plant height decreased, but reproductive development (flowering and fruiting) improved under the 16 h/8 h photoperiod. Meanwhile, foliar spray with 100 or 150 μM Fe-EDTA improved the photosynthetic pigment content, the net photosynthetic rate, and the fruit quality indexes under both photoperiods. Moreover, the content of Fe increased, while the contents of K, Mg, and Mn, and the concentrations of individual and total amino acid decreased in tomato fruits. Under 16 h/8 h photoperiod, the contents of soluble protein, free amino acid, and lycopene significantly increased in tomato fruits by 90%, 84%, and 30%, respectively, after spraying the leaves with 100 μM Fe-EDTA. Similarly, the soluble solids, soluble sugar content, sugar-acid ratio, and vitamin C content in fruits increased by 71%, 171%, 246%, and 14%, respectively, after spraying with 150 μM Fe-EDTA. These results suggest that extending the illumination time to 16 h is beneficial to the development of tomato plants, and foliar application of 150 μM Fe-EDTA under 16 h/8 h photoperiod can best improve the flavor and nutritional quality of tomato fruits.
... Drought is by far the most important environmental stressor in agriculture worldwide, and it is expected to contribute to the severe salinization of more than 50% of world arable land by the year 2050 (Barsanti et al., 2019). It is a normal, recurring feature of climate which occurs in virtually all climatic regions (Goñi, Quille, & O'Connell, 2018). ...
Plants must cope with different environmental stresses during their whole lifetime. Abiotic stresses like drought, salt, mineral nutrition disturbances and temperature stress are commonly interconnected through some physiological events in stressed plants, such as the synthesis of protective plant compounds as a response to stress. Many of these, produced within plant primary or secondary metabolism, act as functional compounds not exclusively in plants but in other organisms as well. Concurrently, many of the active compounds in biostimulants which can support plant stress tolerance and productivity in adverse growth conditions are the metabolites or intermediates that may influence the plant's edible parts nutritional quality. Such effects of biostimulants application are not elucidated enough, therefore, we aimed to give an overview of recent advances in the research related to the interplay among abiotic stress, plant response, biostimulants effects and plant‐derived functional food, focusing on plant metabolites as the link which connects the environment with the food chain.
