Amelioration of Perturbed Phosphorus Metabolism in Mungbean Seedlings Exposed to Sodium Arsenate by Phytohormones and Phosphate Salts

摘要

The effect of Sodium arsenate (Na2HAsO.7H20) on phosphorus content and activities of phosphatase enzymes was examined in mungbean (Vigna radiata (L.) Wilczek seedlings. With the increase in concentration of Sodium arsenate (5,10 and 20uM) there was significant decrease in length of mungbean seedlings. Under arsenate induced stress, phosphorus metabolism was perturbed. The effects were manifested by a decline in phosphorus content and inhibition of activity of key phosphatise like alkaline phosphatase(EC 3.1.3.1) whereas activity of acid phosphatase (EC3.1.3.2) was elevated. These alterations in P metabolism might contribute to metabolic perturbations and decreased growth of mungbean plants in an arsenate polluted environment. Reduction in growth inhibition was achieved by pretreating the seeds with phytohormones (GA3, IAA at 50 uM concentration) and phosphate salts (KH_2PO_4, NaH_2PO_4, 2H20 at 10mM concentration). Pretreatment of mungbean seeds with GA3, KH_2P_2 and NaH_2PO_2.2H20 could ameliorate As induced toxicity to different extent in terms of growth and phosphorus metabolism. Thus, the use of GAj and phosphate salts may help to resist the arsenic toxicity in seedling stage to some extent, in arsenic contaminated areas.