Silicon Supply Improves Leaf Gas Exchange, Antioxidant Defense System and Growth in Saccharum officinarum Responsive to Water Limitation

and exposed for 60 days after Si application. Under stress, reduction in plant length (~26-67%), leaf area-expansion (~7-51%), relative water content (~18-57%), leaf greenness (~12-35%), photosynthetic pigments (~12-67%), physiological responses such as photosynthesis (22-63%), stomatal conductance (~25-61%), and transpiration rate (~32-63%), and biomass production were observed in the plants without Si application. The drought condition also inhibited the activities of antioxidant enzymes like catalase (~10-52%), peroxidase (ca. 4-35), superoxide dismutase (10-44%) and enhanced proline (~73-410%), and malondialdehyde content (ca. 15-158%), respectively. However, addition of Si ameliorated drought induced damage in sugarcane plants. The findings suggest that the active involvement of Si in sugarcane responsive to water stress ranges from plant performance and physiological processes, to antioxidant defense systems.