Increasing New Root Length Reflects Survival Mechanism of Rice (Oryza sativa L.) Genotypes under PEG-Induced Osmotic Stress

Rice is globally one of the most important cereal crops that faces osmotic stress under any kind of abiotic stresses. An experiment was conducted under controlled condition to study the effects of polyethylene glycol (PEG) induced osmotic stress on root and root hair morphology and associated biochemical traits in four morphologically diverse rice genotypes. Plants were grown hydroponically. Two treatments, 0% (control) and 5% PEG 6000 (w/v), were imposed on 38 days old plants for 17 days’ duration. Main root axis length at first three youngest root bearing phytomers (Pr1-Pr3) was increased in Binadhan-11 but decreased in Binadhan-7 and BRRI dhan 71 under 5% PEG treatment compared to control. This result indicated that Binadhan-11 increased new root length perhaps to explore stress free environment. Length of L-type first order lateral root was also significantly increased by 2.03 fold in Binadhan-11 under 5% PEG treatment compared to control. Density and length of root hairs were increased at first order lateral roots in Binadhan-11 under 5% PEG treatment compared to control treatment those contributed largely to root surface area. Measurements of H2O2 and MDA revealed that Binadhan-11 was less affected by the oxidative damage caused by PEG. Data provides insight into the root morphological plasticity of four morphologically diverse rice varieties under PEG-induced osmotic stress.