Mitigation of salinity stress in finger millet through silicon supplementation: Impacts on growth and physiological traits

Finger millet is a vital food crop in Asian and African countries, but its growth and yield can be negatively affected by salt stress. The application of silicon (Si) has been shown to enhance plant stress tolerance. This study investigates the effects of Si supplementation on finger millet under salinity stress. Seeds were grown in plastic pots with garden soil and treated with control, NaCl (200 mM), Si (10 ppm), and NaCl + Si (200 mM + 10 ppm Si). Physiological traits were assessed at one, two, three, and four months after sowing, while agro-morphological traits were evaluated at maturity. Growth parameters significantly declined under the 200 mM NaCl treatment. At each month of analysis, root length was dramatically reduced under salt stress compared to the control. However, Si supplementation under salinity stress significantly improved both shoot and root lengths at all stages of analysis. Silicon application alleviated the negative effects of NaCl, promoting growth and biomass production. Si also enhanced chlorophyll and carotenoid content under salinity stress compared to NaCl alone, while reducing membrane damage. Although osmolyte accumulation increased under salinity, it decreased with Si application, as did the specific activity of antioxidative enzymes. In conclusion, Si application as a fertilizer significantly improves finger millet stand establishment and productivity. The salt-tolerant landrace of finger millet (ST-JA-WA) holds potential for crop improvement programs aimed at enhancing stress resilience.