Uptake by rice seedlings and in-plant degradation of atrazine as influenced by the oxidative stress induced by added arsenic or phosphate deficiency

Abstract

ABSTRACTThe uptake and degradation of atrazine (ATR) by rice seedlings (Oryza sativa L.) was investigated with and without arsenate and phosphate nutrient in the cultured solution over a period of 48 h. The hydrogen peroxide (H2O2) contents in plants under different treatments were measured to evaluate the oxidative stress of the plant cell and its influence on the plant uptake and degradation of ATR. Results indicated that the ATR levels and main degradation products, deethylatrazine (DEA) and deisopropylatrazine (DIA), in plants varied significantly in different treatments. Added arsenate in solution increased the level of DEA and the ratios of DEA to the total (ATR, DEA, and DIA) in roots, while it either increased or decreased the H2O2 content in roots. Added arsenate increased the ratios of degradation products to the total in shoots, which corresponded to the 110%–285% increase of the H2O2 content. In phosphate-deficient systems, the H2O2 contents in shoots increased significantly, especially when exposed to a low level of ATR while the ratios of DIA and DEA to the total in shoots increased. The oxidative stress in rice seedlings induced by arsenic coexisting with ATR and by phosphate deficiency affected the plant uptake and degradation of ATR.