EFFECT OF SODIUM ARSENITE AND SODIUM-CHLORIDE ON BEAN PLANT NUTRITION(MACRONUTRIENTS)

The effects of different levels of arsenic (As) and salinity on bean p lant (Phaseolus vulgaris L., cv. Buenos Aires) nutrition were investig ated. We studied the processes of absorption and accumulation of macro nutrient elements: nitrogen (N), phosphorus (P), potassium (K), calciu m (Ca), and magnesium (Mg). The experiment was performed in soilless c ulture at two levels of As: 2 and 5 mg As . L-1 (added as sodium arsen ite, NaAsO2,), and three saline levels [only sodium chloride (NaCl) wa s added]: 1, 2, and 4 dS.m(-1). Sodium arsenite and NaCl significantly affected macronutrients allocation within bean plant at concentration levels used in this study. Arsenite depressed K, Na, and Mg concentra tions in root, whereas root N, and Ca levels were increased. Nitrogen, P, K, and Na concentrations were significantly higher in As-stressed plants compared with controls. The addition of NaCl increased Ca conce ntration in roots and decreased that of K. Salinity tended to increase leaf concentrations of K, Na, Ca, and Mg; whereas leaf N and P levels decreased with increasing salinity.