Impact of 24-epibrassinolide, spermine, and silicon on plant growth, antioxidant defense systems, and osmolyte accumulation of maize under water stress.

The effect of triad application of the phytohormone 24-epibrassinolide (EBL), the polyamine spermine (Spm), and the element silicon (Si) has not yet been considered on plant growth and behavior in water-stressed conditions. We aimed to evaluate the impact of single/dual/triad application of 24-epibrassinolide (EBL), spermine (Spm), and silicon (Si) on the growth, photosynthetic metabolites, and antioxidant enzymes in the maize plant exposed to water stress. This study was conducted as a potential drought resistance system and plants' maintenance against oxidative damage. In this regard, one maize hybrid (Paya) was grown under well-watered and water-deficit conditions (interrupted irrigation at the flowering and the filling seed stages) with and without foliar spraying of EBL, Spm, and/or Si. Drought conditions remarkably reduced growth, productivity, water-related content (RWC), and chlorophyll content. However, the dual and triad applications of EBL (0.1 mg L-1), Spm (25 mg L-1), and Si (7 mg L-1) significantly improved the above parameters. Water stress considerably augmented the levels of H2O2 and MDA. Their content in stress-subjected plants was significantly reduced by triad application. In water-stressed circumstances and after foliar treatments, the activities of superoxide dismutase, catalase, and peroxidase as well as the amounts of total soluble proteins, phenolic compounds, proline, and glycine betaine all improved. Overall, triad application increased the plant's drought resistance and diminished ROS accumulation by raising the scavenging via the enhanced activity of the antioxidant enzymes.

Effects of biofertilizers and iron nano-oxide on maize yield and physiological properties under optimal irrigation and drought stress conditions.

In this research, effects iron nano-oxide and biofertilizers and chemical was investigated on the yield and some traits of Maize under normal and drought stress conditions in two years (2018 and 2019). The experiment was performed in the form of split-spilt plot in a complete random block design with three replications. The studied irrigation treatment included three levels (normal, 85% and 65% optimum water requirement) in the main plots and iron nano-oxide at four levels (0, 0.5, 1, and 1.5 g/L) in subplots, and biofertilizers at four levels (noninoculation, inoculation with mycorrhiza, inoculation with pseudomonas and combined inoculation of mycorrhiza and pseudomonas) in sub-plots. The results showed that grain yield, 1000-grain weight, and leaf chlorophyll contents decreased by drought stress. Use of pseudomonas and mycorrhiza increased these traits in normal and stress conditions, but iron nano-oxide had no significant effect on the measured traits. Also, drought stress increased malondialdehyde, ion leakage, catalase, peroxidase, proline, and polyphenol oxidase in both light and severe stress regimes. The amount of antioxidant enzymes increased under drought stress conditions in corn. The results indicated that all the characteristics measured by double inoculation with Pseudomonas and Microoriza had the best performance in conditions of water shortage and the use of these biofertilizers increases yield, 1000-seed weight, and chlorophyll content of maize. Also, the use of biofertilizers modulates the effect of drought stress and reduces its negative effects.