Silicon alleviates PEG-induced osmotic stress in finger millet by regulating membrane damage, osmolytes, and antioxidant defense

Abstract

Drought restricts plant growth and productivity. Silicon has beneficial effects on imparting drought tolerance in plants. Present work was intended to evaluate the effect of Si on polyethylene glycol-6000 (PEG) induced osmotic stress in local landraces of finger millet. The seeds of stress-tolerant and stress-sensitive landraces of finger millet were treated with distilled water, 15% PEG, and PEG+Si (5-25 ppm). The ameliorative effect of Si was evaluated in terms of percentage seed germination, seedling growth, accumulation of osmolyte and activity of antioxidative enzymes. PEG-induced osmotic stress reduced seed germination, seedling growth, and augmented osmolyte accumulation. It also elevated the levels of antioxidant enzymes. The exogenous supplementation of silicon significantly improved seed germination as well as early seeding growth. Positive effects of Si were reflected in decline in malondialdehyde (MDA) content and improved glycine betaine content and antioxidant enzymes in PEG-induced stress tolerant as well as susceptible landraces. The Si-induced ameliorated effects on all the parameters studied were more pronounced in the stress-tolerant landrace (FM/ST/01) than the stress-sensitive landrace (FM/RT/01). These results clearly indicate advantageous effects of Si in relieving PEG-induced stress during seed germination and early seeding growth and suggest a possibility of better stand establishment by application of silicon containing fertilizer during seed sowing.