PHYSIOLOGICAL RESPONSES OF RICE (Oryza sativa L.) TO ZINC TREATMENTS UNDER DROUGHT STRESS

Abstract

Rice, as one of the major cereal crops, is severely affected by water deficit in many regions. To better understand zinc role under drought stress, a hydroponic trial was conducted in the Bogor Agricultural University greenhouse where daytime temperature were 34oC to investigate the effects of zinc on plant growth, antioxidant enzyme activities, and malondialdehyde content in two rice cultivars IR64 and INPAGO5 under drought stress. Rice seedlings were grow on modified Yoshida nutrient solution with three different zinc concentrations, i.e., 0.15, 0.3 and 0.6μM and one control. The results showed that zinc promoted rice growth subjected to drought by increasing leaf length, plant height and root length in both rice cultivars except leaf length of INPAGO5 prior drought stress. Superoxide dismutase and catalase activities were significantly increased in IR64. In INPAGO5, increase of catalase activity was not significant, whereas superoxide dismutase activity was significantly increased. Peroxidase activity was less in INPAGO5 than that of IR64. Malondialdehyde accumulation resulting from lipid peroxidation was significantly reduced in root cell of both cultivars under zinc treatment after 8 days of drought. These results suggest that zinc application increased antioxidant enzyme activities and resistance to drought stress. Among zinc concentrations applied, 0.3μM seems more beneficiary for rice to overcome drought stress. An adequate zinc concentration could be useful in preventing any damage in case of short period of drought.