Silicon-mediated modulation of physiological attributes, and pollen morphology under normal and water-deficit conditions in rice (Oryza sativa L.)

Drought, in the changing climatic conditions of the world, is a major obstruction to rice production and productivity. Silicon has been recognized as a vital element advantageous in combating various environmental stresses in crops. Five genotypes of rice (Oryza sativa L.) were selected to investigate the regulation of superoxide dismutase (SOD), proline and malondialdehyde (MDA) under normal and water-deficit conditions when exogenously supplemented with silicon. A field study for two successive years was laid out with four treatments viz. Control (T1), Si fertilized (T2), Si + Drought stress (T3) and Drought stress (T4). Results displayed that silicon-supplemented rice plants under water-deficit conditions had a significantly enhanced SOD activity increasing from 34.85 U/g fresh wt/min in case of drought-inflicted plants to 61.08 U/g fresh wt/min for Si-supplemented drought-inflicted plants. The proline and MDA content was reduced by 42% and 40% in the case of Si-added drought-stressed plants. The pollen study also unveiled the beneficial effect of silicon to cope with drought stress, while shrinkage of pollens was observed in drought conditions