Silicon-induced modulations in growth, physiological, biochemical and root attributes of Soybean (Glycine max L.) under drought stress

Abstract Purpose : One of the main abiotic stresses that reduces crop production globally is drought. Among various strategies to improve drought tolerance in plants, the treatment of silicon is very feasible method as it has potential to improve stress tolerance in soybean. The present experiment was conducted to determine the drought stress tolerance in response to application of silicon (Si) in soybean. Methods : In present study, different treatment levels were i) Two different field capacity levels (100% F.C and 60% F.C) ii) Four levels of silicon 0 kg/ha, 100kg/ha, 200 kg/ha and 300 kg/ha were applied, and sand culture was used as sowing media at vegetative stage (15 days after emergence). Results : The results of present study revealed that plant biomass was significantly improved by application of silicon, such as leaf area, dry and fresh weight of root and shoot and shoot and root length. Shoot length reduced upto 23% and root length increased upto 24% under drought stress conditions contradictory to control while application of silicon (200kg/ha) considerably enhanced the shoot and root length upto 45% and 85%. Leaf osmotic potential (LOP) decreased upto 5% under stress conditions as compared to control while the (LOP) increased 27% with the application of silicon (200kg/ha). Gas exchange parameters and soluble proteins were significantly reduced under water deficit conditions. Silicon application (200kg/ha) prominently improved the total soluble proteins and gas exchange parameters. chlorophyll a,b were enhanced upto 32% and 24% in comparison to the control. Root surface area increased under stress conditions and enhanced by application of silicon and maximum improvement was observed in treatment where silicon was applied @200kg/ha. Enzymatic antioxidants (SOD, POD and CAT) reduced under drought stress but silicon significantly enhanced the enzymatic antioxidants upto 19%, 53%, 30% in comparison to stress In conclusion , the soil applied silicon at 200kg/ha enhanced plant growth, photosynthetic pigments, osmolytes, antioxidants, and lowered oxidative stress determinants to ameliorate drought stress condition.