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Water deficit is perhaps the most severe threat to sustainable crop production in the conditions of changing climate. Researchers are striving hard to develop resistance against water deficit in crop plants to ensure food security for the coming generations. This study was conducted to establish the role of fulvic acid (FA) application in improving the performance of hybrid maize (Zea mays L.) under drought. Maize plants were grown under normal conditions till tasselling and were then subjected to drought by cessation of water followed by foliar application of FA (1.5 mg l−1). Drought stress disrupted the photosynthetic pigments and reduced the gas exchange leading to reduction in plant growth and productivity. Nonetheless, exogenous FA application substantially ameliorated the adversities of drought by sustaining the chlorophyll contents and gas exchange possibly by enhanced levels of antioxidant enzyme (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) activities and proline. These beneficial effects yielded in terms of plant growth and allometry, and grain yield. It is interesting to note that FA application also improved the crop performance under well‐watered conditions. Hence, FA may be applied to improve the crop performance under drought and well‐watered conditions.

Methyl jasmonate (MeJA), a plant-signalling molecule, is involved in an array of plant development and the defence responses. This study was conducted to explore the role of exogenous MeJA application in alleviating the adversities of drought stress in soybean (Glycine max L. Merrill.). Soybean plants were grown under normal conditions until blooming and were then subjected to drought by withholding irrigation followed by foliar application of (50 lm) MeJA. Drought stress substantially suppressed the yield and yield-related traits, whereas it accelerated the membrane lipid peroxidation. Nonetheless, substantial increase in activities of enzymatic antioxidants (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), proline, relative water contents (RWC) with simultaneous decrease in membrane lipid peroxidation was observed in MeJA-treated plants under drought. These beneficial effects led to improvement in biological and grain yield, and harvest index under drought. Interestingly, MeJA application was also useful under well-watered conditions. These results suggest the involvement of MeJA in improving the drought tolerance of soybean by modulating the membrane lipid peroxidation and antioxidant activities.

Brassinolides (BRs) are naturally occurring substances, which modulate plant growth and development events and have been known to improve the crop tolerance to abiotic stresses. In this study, possible role of exogenously applied brassinolide (BR) in alleviating the detrimental effects of drought in maize was evaluated in a rain-protected wire-house. Maize was subjected to drought at the start of tasseling for 6 days by withholding water application followed by foliar spray of BR (0.1 mg l−1) to assess the changes in growth, gas exchange, chlorophyll contents, protein, relative leaf water contents (RLWC), proline, malonialdehyde (MDA) and enzymatic antioxidants. Drought substantially reduced the maize growth in terms of plant height, leaf area and plant biomass. Moreover, substantial decrease in gas exchange attributes (net photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), water use efficiency (WUE), instantaneous water use efficiency (WUEi) and intercellular CO2 (Ci) was also recorded. However, exogenous application of BR remarkably improved the gas exchange attributes, plant height, leaf area, cobs per plant, seedling dry weight both under drought and well-watered conditions. BR-induced promotion in growth and physiological and metabolic activities were mediated through increased protein synthesis enabling maintenance of tissue water potential and activities of antioxidant enzymes lowering the lipid peroxidation under drought.