Acetate alleviates As toxicity via improving ROS metabolism and antioxidant defense system in lentil seedlings

Abstract

Arsenic (As) is a toxic element which entries the food chain from the soil through plants and poses a great threat to human health. Also, an excess of As causes adverse physiological and biochemical changes in plants. In the present study, the mechanism of As tolerance in acetate-treated lentil seedlings was investigated. Six-day-old seedlings pretreated with or without 10 mM Na-acetate were exposed to two levels of sodium arsenate (250 and 320 µM) for four days. The results showed that both levels of As caused severe chlorosis, growth reduction, and water imbalance. Furthermore, As-induced oxidative damage in the plants was manifested by higher malondialdehyde and, hydrogen peroxide content, electrolyte leakage, and disruption of the antioxidant defense pathway. However, acetate pretreatment improved growth and chlorophyll content, and reduced oxidative damage by upregulating some components (catalase and ascorbate) of the antioxidant defense pathway in the seedlings. Under As stress, accumulation of As was found in both roots and shoot of lentil. However, acetate pretreatment reduced As accumulation in the roots and inhibited the transfer of As to the shoots in the seedlings. Taken together, the results suggest that acetate can enhance tolerance against As toxicity in lentil seedlings by reducing As accumulation and increasing ROS detoxification through the antioxidant defense pathway.