Nitric oxide modified growth, nutrient uptake and the antioxidant defense system in tomato seedlings stressed with arsenic

Nitric oxide is a gaseous molecule that improves the defense system of plants under stress. This study investigated whether the application of exogenous nitric oxide (NO) improves the growth, nutrient uptake, defense system and modifies the translocation of arsenic (As) in tomato seedlings. NO was applied via foliar using sodium nitroferricyanide at 0, 50, 100 and 150 mu M, while As contamination in irrigation water was simulated using a single dose of As(V) (3.2 mg L-1). NO at 100 and 150 mu M, in the presence of As(V), decreased the height of the seedling and increased the number of leaves. NO at 100 mu M, in the presence and absence of As(V), decreased chlorophylls, while As(V) increased them. NO improved seedling nutrient uptake and concentration in the presence of As. NO did not improve arsenic translocation. NO at 50 mu M reduced the H2O2 concentration in roots. NO at 150 mu M, in the presence of As(V), reduced the enzymatic activities of SOD, GPX and APX in roots, increased the GSH concentration in roots, and decreased the GSH concentration in leaves.