Effects of exogenous proline treatment on antioxidant and biochemical parameters in Lepidium sativum L. plants cultivated in a water-stressed condition

Proline, an organic compatible solute that acts as an osmoprotectant, is a crucial part of many plant's responses to water stress. In the current study, the impact of proline on enzymatic, non-enzymatic antioxidant and biochemical parameters in Lepidium sativum L. growing under water stress was examined. Plants were raised in controlled environments with a temperature of 25°C 16 h of light and 8 h of darkness. The concentrations of 50 ?g/L, 100 ?g/L and 250 ?g/ L proline were standardized and applied to plants grown under different water potential of -0.01?w MPa, -0.02?w MPa and -0.03?w MPa through foliar spray. After 35, 75 and 110 days of plant growth, the enzymatic antioxidants catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, glutathione peroxidase, glutathione-s-transferase activity and non-enzymatic antioxidants like phenols, ascorbic acid, tocopherol, flavonoid content, were measured. The foliar application of proline increased enzymatic and non-enzymatic antioxidant assay activity in stressed growing plants compared to control plants. However, lipid peroxidation was reduced in water stressed plant due to proline application. The present study investigated that proline played a significant role in overcoming water stress in L. sativum. Moreover, this study supported that L. sativum plant copes with water stress by foliar application of proline.