Phytoaccumulation potential and enzymatic activities of Oryza sativa L. genotypes exposed to Cr (VI) in hydroponic culture

Abstract

In this work, the phytoaccumulation efficiency and enzymatic activities of various rice (Oryza sativa L.) genotypes exposed to differential concentrations of Cr (VI) have been studied. The cultivars experimented were Pratikshya, Sankar, Annapurna, White swarna and Pimpudibasa. The seedlings were raised with ¼ strength Hoagland’s nutrient solution prepared in deionised water supplemented with different concentrations (0, 100, 200, 300 and 400µg/L) of hexavalent Cr as potassium dichromate (K2Cr2O7) under controlled environmental conditions. The seedlings were harvested at 7 days intervals and parameters like root and shoot elongation, enzymatic activities and tolerance to chromium ions were measured after different periods of exposure. The highest concentration of Cr (VI) ions in shoots (9.92 µg/g dry weight) and roots (8.51µg/g dry weight) was found in Pratikshya exposed to 300 µg/L of Cr(VI) after 21 days of treatments. The growth parameters of five cultivars and tolerance to chromium were in the order of Pratikshya>Sankar>Annapurna>White swarna>Pimpudibasa. Cr(VI) toxicity was correlated with peroxidase and catalase enzyme activities of different rice cultivars. The interaction between chromium ions and rice cultivars biomass was studied using SEM-EDX and FTIR analysis.