Drought Tolerant of Rice (Oryza sativa L) Implication Through Antioxidant Defense Mechanism

An experiment was conducted at department of Crop Physiology, Assam Agricultural University, Jorhat under rain out shelter to assess the responses of selected upland rice varieties, ARC-10372, Lachit, Bandana, Maibee and Kopilee to moisture stress. Moisture stress was imposed by withholding water. Water deficit resulted in a significant increase in H2O2 content thereby increased lipid peroxidation in terms of malondialdehyde (MDA) accompanied by reducing the membrane stability index and consequently reduced the relative water content (RWC) compared to control. Moisture stress significantly increases the activities of antioxidative enzymes namely superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, glutathione reductase in all the varieties. Antioxidatant enzymes activities were significantly increased in ARC-10372 and Maibee thus restoring the membrane integrity and enhancing the defence system and it may be suggested that the enhancement of antioxidants in the both of rice varieties of drought tolerance under stress condition.