Abstract

Six genotypes of rice viz., IET 20710, IET 20894, IET 20716, MTU 1010, IET 20744 and Swarna, were examined in sand culture with two P levels in modified Hoagland solution (Low phosphorus–LP: 1.6 μM and Normal phosphorus–NP: 200 μM). Physiological and biochemical parameters of root and leaves were evaluated in response to P supply. Root length was significantly higher while root volume and dry weight were lower in plants with LP. Among rice genotypes viz., IET 20710, Swarna and IET 20716 exhibited higher length of roots with less reduction in root volume and dry weight and higher root: shoot ratio indicative of adaptation to low P conditions. These genotypes had higher levels of antioxidant enzyme activities (SOD, POD and CAT) and lower MDA content in leaves and roots under low P conditions indicative of less oxidative injury. In contrast, IET 20744 and IET 20894 genotypes with LP supply exhibited reduction in root traits, higher levels of MDA content and reduced antioxidant enzyme activities.