TY - JOUR AU - Panda, Debabrata AU - Sahoo, Ritesh S. AU - Behera, Prafulla K. AU - Barik, Jijnasa AU - Nayak, Jayanta K. T1 - Leaf Photochemical Activity and Antioxidant Protection in Selected Hill Rice Genotypes of Koraput, India in Relation to Aluminum (Al3+) Stress JO - Journal of Stress Physiology & Biochemistry Y1 - 2020 VL - 16 IS - 2 SP - 13 EP - 21 UR - http://www.jspb.ru/issues/2020/N2/JSPB_2020_2_13-21.pdf KW - Antioxidant enzymes KW - Al3+ tolerance KW - chlorophyll fluorescence KW - traditional rice U1 - 1997-0838 N2 - Genetic variation for Aluminum (Al3+) tolerance is prerequisite for developing cultivars with improved tolerance to Al3+ stress. The present study aims to assess genotypic variability of growth, photosynthesis along with antioxidant defense in popular hill rice landraces of Koraput, India under different concentrations of Al3+ and compare the responses with modern rice varieties to identify Al3+ tolerant rice genotypes. After exposure to different level of Al3+, the growth parameters such as shoot length, root length, fresh and dry weight of rice seedlings were significantly (P<0.05) inhibited in the studied genotypes compared to the control seedlings. Significant (P<0.05) reduction in SPAD index, chlorophyll and carotenoid content was observed in all rice seedlings under high concentration of Al3+. Higher concentration of Al3+ also alters the photo system (PS) II activity, as revealed in the reduction in the values of maximal fluorescence (Fm), maximum photochemical efficiency of PSII (Fv/Fm), yield of photochemical efficiency [Y(II)] and photosynthetic quenching (qP) with concomitant increase of minimal fluorescence (Fo) and non-photosynthetic quenching (NPQ). The antioxidant enzymes activities such as superoxide dismutase, ascorbate peroxidase and guaiacol peroxidase were increased in rice seedlings under elevated Al3+ concentrations. Taken together, hill rice landraces namely; Kalajeera, Machakanta, Haladichudi showed superior photochemical activity and better antioxidant protection than that of IR 64 cultivar. These hill rice landraces are identified as potential donors for the Al3+ tolerance breeding program. ER -