Evaluation of effectiveness of seed priming with selenium in rice during germination under arsenic stress

Due to extensive use of arsenic (As) contaminated ground water in rice cultivation As toxicity has become a growing concern to rice growers of south east Asian countries. The presence of As in soil and irrigation water causes impaired crop growth and development. Selenium (Se) at lower concentration (1.0 mg L^-1) is reported to be stimulatory on crop growth and it has also an antagonistic behavior with As. With this rationale the present study was conducted to investigate into the potentiality of seed priming technology with Se to ameliorate the As stress on rice seed germination and seedling growth. The seed germination percentage, seedling growth, total phenolics, proline and malonaldehyde content as well as total As uptake pattern of rice seedlings grown under As stressed condition were measured. The As induced toxicity markedly reduced the germination percentage by 70%, whereas, Se supplementation through seed priming enhanced the rice seed germination by 9% and root and shoot length vis-a-vis seedling biomass accumulation by 1.3, 1.6 and 1.4 fold respectively. The inhibitory effect of As stress was more on root growth than that of shoot. The toxicity due to arsenite stress was higher than the arsenate stress. Seed priming with Se enhanced seed germination and seedling growth by reducing As uptake, suppressing the oxidative damage through increase in antioxidants accumulation in rice seedlings. Seed primed with 0.8 mg Se L^-1 was more effective in improving rice seed germination and seedling growth, compared to 1.0 mg Se L^-1.