Protective role of manganese, proline and rice straw extract in wheat against drought driven oxidative stress

The drought stress intensity associated with climatic changes alters plant physiology and leads to minute growth and crop yields around the globe. The foliar application of proline, manganese (Mn) and rice straw extract (RSE) can be proven as an effective strategy to counter drought stress-related deleterious effects. The literature about the collaborative role of Proline, Mn, and RSE as foliar spray application under drought stress is silent to this date. The objective of this study was to induce tolerance against drought stress to sustain maximum growth and yield of wheat varieties (Anaj-17 and MH-2021), with foliar applications of proline, Mn, and RSE. A field experiment was conducted to disclose the protective role of these substances in wheat varieties under water stress. Two irrigation levels, i.e., control (normal irrigation) and water stress (water deficit irrigation), and 5 levels of Mn, proline and RSE i.e., control (water spray), Mn (0.1%), proline (1.0%), RSE (10%), and mixture (Mn + proline + RSE) in a 1:1:1 ratio were applied. Application of proline, Mn and RSE improved the chlorophyll pigments (Chlorophyll a, b) and carotenoids, growth (root and shoot length), biomass (root and shoot fresh and dry weight), and yield characters (grain yield/plant and 100-grain weight) of both wheat varieties under water deficit stress. A significant increase in enzymatic antioxidants; catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and non-enzymatic antioxidants (anthocyanin, proline, free amino acids, and phenolics) was recorded under drought stress and foliar spray treatments. The foliar applications of these substances also reduced the drought-driven overproduction of lipid peroxidation (MDA) and hydrogen peroxide (H₂O₂) significantly. The results suggested that Anaj-17 variety is more tolerant to drought stress than MH-21 variety, while combined treatment (proline + Mn + RSE) was found to be the most effective among all applications.