Exogenous Application of Silicon and Brassinosteroids Alleviate the Adversities of Drought Stress on Maize through Up-Regulation of Photosynthetic Efficiency, Antioxidants Defense System and Osmotic Adjustment
摘要
Drought stress is a critical factor limiting maize productivity by impairing physiological and biochemical processes. Current experiment was carried out to investigate single and collaborative potential of silicon (Si) and brassinosteroids (BR) to alleviate the negative impact of drought on maize. Experiment was comprised of control treatment 80% water holding capacity (WHC), 40% WHC drought (DS), DS + 4 mM Si, DS + 5 µM BR and DS + 4 mM Si + 5 µM BR. Physiological assessment revealed that Si and BR application significantly mitigated drought-induced reductions in photosynthetic pigments and photosynthetic rate which improved photosynthetic efficiency. Moreover, biochemical analysis showed that treated plants exhibited elevated enzymatic antioxidant activities such as catalase, peroxidase and superoxide dismutase that caused reduction in oxidative stress. These enhancements in antioxidant defense were correlated with lower levels of malondialdehyde (MDA) by reducing membrane lipid peroxidation under drought conditions. Additionally, Si and BR treatments promoted osmotic adjustment by increasing the concentration of osmolytes, which helped to maintain cellular turgor and water retention. Overall, the collective use of Si and BR showed more effective results than individual treatments, enhancing maize crop’s drought tolerance by enhancing the photosynthetic efficiency, antioxidants activities, and improving osmotic balance. These outcomes climax the potential of Si and BR as agronomic strategies for sustaining maize productivity under drought stress, providing insights into physiological and biochemical pathways that could be targeted in future crop improvement programs.