The key roles of salicylic acid and sulfur in plant salinity stress tolerance

The salinization of agriculture soils over the globe has become one of the most devastating stresses and is significantly limiting cultivated land area, and crop productivity and quality. It is very imperative to explore both salinity tolerance in plants and insights into approaches (and underlying mechanisms) for effectively controlling salinity impacts. To this end, the role of phytohormone salicylic acid (SA) and plant nutrient sulfur (S) in promoting salinity tolerance has been researched in isolated studies, and SA–S interaction results have been little discussed. Given this, taking into account recent literature on SA, S and soil salinity, this paper aimed to (i) overview of the major impacts of soil salinity on plant health; (ii) highlight the significance of SA and S in improving plant salinity tolerance; (iii) discuss the role and underlying mechanism of SA, S and their interaction in the modulation of plant growth and development under salinity stress; and also to (iv) appraise the discussed literature and enlighten the major prospects

Biophysical and Biochemical Markers of Metal/Metalloid-Impacts in Salt Marsh Halophytes and Their Implications

As a major sink, estuarine/salt marsh ecosystem can receive discharges laden with myriads of contaminants including metals/metalloids from man-made activities. Two among the major consequences of metal/metalloid-exposure in estuarine/salt marsh ecosystem flora such as halophytic plants are: (a) the excessive accumulation of light energy that in turn leads to severe impairments in the photosystem II (PS II), and (b) metal/metalloids-accrued elevation in the cellular reactive oxygen species (ROS) that causes imbalance in the cellular redox homeostasis. On one hand, plants adopt several strategies to dissipate excessive energy hence eventually to avoid damage in the PS II and maintain optimum photosynthesis. On the other hand, components of the cellular redox system quickly respond to metal/metalloid-exposure, where plants try to maintain a fine-tuning among these components, and tightly control the level of ROS and its potential consequences. Herein, major insights into, and the significance and implications of important biophysical and biochemical markers in metal/metalloid-exposed halophytes are overviewed and also highlighted main aspects so far least explored in the present context. Discussion advocates to regularly monitor and integrate studies on the highlighted herein biophysical and biochemical markers taking into account the missing aspects such as essential and non-essential metal/metalloid-speciation, -availability, and -methylation, role of the obvious microbial activities, and a comparative account of the outcomes of the studies on mixture of metal/metalloid performed in laboratory and field conditions. Thus, consideration of these missing aspects in future studies on the subject can help us to: (a) unveil the status of the metal/metalloid-contamination and -impact; (b) understand adaptive responses of salt marsh halophyte to metals/metalloids, and also (c) to devise sustainable strategies for the environmental or ecosystem management and safety.info:eu-repo/semantics/publishedVersio

Improving Growth and Productivity of Oleiferous Brassicas under Changing Environment: Significance of Nitrogen and Sulphur Nutrition, and Underlying Mechanisms

Mineral nutrients are the integral part of the agricultural systems. Among important plant nutrients, nitrogen (N) and sulphur (S) are known essential elements for growth, development, and various physiological functions in plants. Oleiferous brassicas (rapeseed and mustard) require higher amounts of S in addition to N for optimum growth and yield. Therefore, balancing S-N fertilization, optimization of nutrient replenishment, minimization of nutrient losses to the environment, and the concept of coordination in action between S and N could be a significant strategy for improvement of growth and productivity of oleiferous brassicas. Additionally, positive interaction between S and N has been reported to be beneficial for various aspects of oilseed brassicas. The current paper updates readers on the significance of N and S for the improvement of plant growth, development, and productivity in detail. In addition, S-N nutrition-mediated control of major plant antioxidant defense system components involved in the removal and/or metabolism of stress-induced/generated reactive oxygen species in plants (hence, the control of plant growth, development, and productivity) has been overviewed

Role of Phytochelatins in Redox Caused Stress in Plants and Animals

Varied environmental compartments (such as soil and water) potentially contaminated with different metals/metalloids can impact the health of both plants and animals/humans. Trace amounts of Cu, Mn, Mo, Ni and Zn are beneficial for higher plants, whereas, Cr, Cu, Co, Mn, Mo, Se, V and Zn are known as the micronutrient metal/metalloids for animals/humans. However, elevated levels of the metals/metalloids can cause severe toxic consequences in both plants and animals/humans. Common in plants and animals/humans, phytochelatins (PCs), the principal non-protein, S-rich, thiolate peptides, protect (through different mechanisms) cellular functions and metal/metalloid homeostasis by performing their chelation and/or detoxification. With the major aim of broadening the current knowledge on the subject, this chapter (a) overviews PCs’ role and modulation separately in metal/metalloid-exposed plants and animals/humans; (b) discusses major methods for determination of PCs and bioassays for enzymes involved in PC synthesis; (c) evaluates the connection of PCs with bionanoparticles; and finally (d) highlights so far unexplored aspects in the present context

Phytohormones-Assisted Management of Salinity Impacts in Plants

The salinity of soils has been significantly limiting crop production in most arid and semi-arid regions of the world. Plant hormones (phytohormones), small molecules with versatile roles in plants can be a sustainable approach for minimizing the major salinity-impacts in plants. Most phytohormones are reported to regulate various signaling cascades interrelated with plant development and stress-resilience and -coping mechanisms. In addition to regulating photosynthesis and related variables, phytohormones also modulate nutrient homeostasis, source-sink capacity, osmoregulation, and antioxidant defense systems in plants under abiotic stresses including soil salinity. Molecular studies have confirmed the coordination between phytohormones and signaling networks, which in turn also maintains ionic homeostasis and plant-salinity tolerance. This chapter aims to appraise the literature available on the role of 10 well-characterized stress response hormones (abscisic acid, ABA; ethylene; salicylic acid, SA; jasmonic acid, JA; and nitric oxide, NO) and also other growth-promoting hormones (such as auxins, gibberellins, GA; cytokinins, CKs; brassinosteroids, BRs; and strigolactones, SLs) in the management of salinity impacts in plants. The discussion outcomes may help in devising and furthering the strategies aimed at sustainably strengthening plant-salinity tolerance

Editorial: Redox Homeostasis Managers in Plants under Environmental Stresses

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Potassium-induced alleviation of salinity stress in Brassica campestris L.

Salinity is an important abiotic factor that adversely affects major agricultural soils of the world and hence limits crop productivity. An optimum mineral-nutrient status of plants plays critical role in determining plant tolerance to various stresses. A pot experiment was conducted on mustard (Brassica campestris L.) to study the protective role of added potassium (K, 40 mg kg-1 soil) against salinity-stress (0, 40 and 80 mM NaCl)-induced changes in plant growth, photosynthetic traits, ion accumulation, oxidative stress, enzymatic antioxidants and non-enzymatic antioxidants at 30 days after sowing. Increasing NaCl levels decreased the growth, photosynthetic traits and the leaf ascorbate and glutathione content but increased the leaf ion accumulation and oxidative stress, and the activity of antioxidant enzymes. In contrast, K-nutrition improved plant growth, photosynthetic traits, activity of antioxidant enzymes and the ascorbate and glutathione content, and reduced ion accumulation and oxidative stress traits in the leaves, more appreciably at 40 mM than at 80 mM NaCl. The study illustrates the physiological and biochemical basis of K-nutrition-induced NaCl tolerance in mustard as a means to achieving increased crop productivity in a sustainable way.Authors are grateful to Hamdard National Foundation (HNF), New Delhi, India for financial assistance for the work. Authors sincerely thank to Dr. Ali Qadar of Central Soil Salinity Research Institute (CSSRI), ICAR, Karnal, Haryana (India) for his valuable critical comments on the second version of this manuscript, and colleagues and staffs at Department of Botany, Hamdard University, New Delhi, for their kind support and encouragements.publishe

The cientificWorldJOURNAL Review Article Improving Growth and Productivity of Oleiferous Brassicas under Changing Environment: Significance of Nitrogen and Sulphur Nutrition, and Underlying Mechanisms

Mineral nutrients are the integral part of the agricultural systems. Among important plant nutrients, nitrogen (N) and sulphur (S) are known essential elements for growth, development, and various physiological functions in plants. Oleiferous brassicas (rapeseed and mustard) require higher amounts of S in addition to N for optimum growth and yield. Therefore, balancing S-N fertilization, optimization of nutrient replenishment, minimization of nutrient losses to the environment, and the concept of coordination in action between S and N could be a significant strategy for improvement of growth and productivity of oleiferous brassicas. Additionally, positive interaction between S and N has been reported to be beneficial for various aspects of oilseed brassicas. The current paper updates readers on the significance of N and S for the improvement of plant growth, development, and productivity in detail. In addition, S-N nutrition-mediated control of major plant antioxidant defense system components involved in the removal and/or metabolism of stress-induced/generated reactive oxygen species in plants (hence, the control of plant growth, development, and productivity) has been overviewed

ATP-sulfurylase, sulfur-compounds, and plant stress tolerance

Sulfur (S) stands fourth in the list of major plant nutrients after N, P, and K. Sulfate (SO42-), a form of soil-S taken up by plant roots is metabolically inert. As the first committed step of S-assimilation, ATP-sulfurylase (ATP-S) catalyzes SO42--activation and yields activated high-energy compound adenosine-5′-phosphosulfate that is reduced to sulfide (S2-) and incorporated into cysteine (Cys). In turn, Cys acts as a precursor or donor of reduced S for a range of S-compounds such as methionine (Met), glutathione (GSH), homo-GSH (h-GSH), and phytochelatins (PCs). Among S-compounds, GSH, h-GSH, and PCs are known for their involvement in plant tolerance to varied abiotic stresses, Cys is a major component of GSH, h-GSH, and PCs; whereas, several key stress-metabolites such as ethylene, are controlled by Met through its first metabolite S-adenosylmethionine. With the major aim of briefly highlighting S-compound-mediated role of ATP-S in plant stress tolerance, this paper: (a) overviews ATP-S structure/chemistry and occurrence, (b) appraises recent literature available on ATP-S roles and regulations, and underlying mechanisms in plant abiotic and biotic stress tolerance, (c) summarizes ATP-S-intrinsic regulation by major S-compounds, and (d) highlights major open-questions in the present context. Future research in the current direction can be devised based on the discussion outcomes

Sustainable Management of Phosphorus in Agriculture for Environmental Conservation

Phosphorus (P) is an essential macronutrient for plant growth and development. Although the P-concentration in soil is 1000 folds higher than in plants, it is rarely available for plant uptake due to low diffusion and high fixation rate in soil. Hence, plants experience P-deficiency in the absence of P-fertilization, which may cause approximately a 30–40% decrease in crop yield. This highlights the importance of using a large amount of phosphate fertilizers to meet crop demands. As P-fertilizer is derived from a nonrenewable and finite source of rock phosphate, this resource is decreasing over time. In addition, farmers are applying P-fertilizers randomly without considering the soil stock, which leads to the loss of P-resources. The low P-use-efficiency (PUE) of plants in the field condition (15–20%) highlights that most of the soil-applied P remains unavailable to plants, and excess P causes ground and surface water contamination (i.e., eutrophication) through leaching and runoff, which ultimately results in environmental pollution. Therefore, it is crucial to apply P-fertilizers considering the soil test value and PUE to protect the environment from contamination and sustainable management of P-resources. This chapter mainly focuses on the sustainable management of P in agricultural fields for environmental conservation