EFFECT OF ARSENIC TOXICITY UNDER DIFFERENT NITROGEN REGIME ON NITRATE UPTAKE IN CHLORELLA VULGARIS

This study examined the effect of 25.0 and 50.0 μM arsenic (As) on nitrate uptake in Chlorella vulgaris when grown under different nitrogen regime. The changes in nitrate uptake of test alga exposed to As under different N regimes show that the control cultures of test alga showed maximum nitrate uptake in N enriched cells. The nitrate uptake under normal N level was decreased by 18.05% (25.0 μM As) and 26.24% (50.0 μM As). Likewise, under N deficient condition, both concentrations (25.0 and 50.0 ?M) of As reduced the nitrate uptake of the test organism by 78.14% and 88.46%, respectively. The effect of As was same during excess N condition, where nitrate uptake of the test organism was reduced by 8.75% and 20.52% at 25.0 and 50.0 ?M As, respectively. More experimental and molecular evidences will further enhance our understanding about the relation of nitrogen regimes with metal tolerance in algae.