Moderate Uranium Disturbs the Nutritional Status and Induces Oxidative Stress in Pisum sativum L.

Environmental contamination by radionuclides particularly uranium is a serious problem at many contaminated sites worldwide. In our present report, we explored production of NO and H2O2 in Pisum sativum, as well as micro/macro elements uptake after uranium addition. Hydroponically grown plants (in amended Hoagland medium) were treated with two different concentration of uranium ([U]=25 and 50 μM respectively) for 5 days. Plants showed a decrease in NO production in [U]=50 μM treatments in both root/ leaves by DAF-2DA staining in comparison to control. On the other hand, production of H2O2 was enhanced in both root/leaves after treatment with [U]=50 μM in comparison to control by DCF-DA staining. Uptake of Fe, K, P, S, and Cu was higher in roots than in shoots. Only Ca uptake was higher in shoots rather than roots in all plants with or without U treatment. Mg and Zn was also higher in shoots of [U] =50 μM treated plants. U accumulation was also higher in roots rather than shoots. Our observation suggests U severely disturbed the nutritional status of P. sativum, a situation that could induce alterations in cell metabolism and thereby stunt growth. Other negative effect of U on plant growth paralleled the observed increase of H2O2 and oxidative damage to root and leaves membranes of P. sativum plants, suggesting that oxidative stress is involved in the toxic mechanism of U. Therefore, the reduction of NO induced by U in the present work could contribute to the accumulation of ROS and oxidative stress.