The influence of arsenite concentration on arsenic accumulation in tomato and bean plants

Arsenic (As) absorption by tomato (Lycopersicum esculentum Mill) and bean (Phaseolus vulgaris L.) as affected by arsenite concentration in nutrient solution was examined. The processes of As uptake and accumulation among roots, stems, leaves, and fruit were studied. Tomato and bean plants were grown in nutrient solution containing four levels of arsenite: 0, 2, 5, and 10 mg As l(-1) were dead after 36 days of treatment. In tomato, As exposure resulted in a significant reduction in dry biomass production but tissue chlorosis or necrosis were not observed. The strategy developed by tomato plants to tolerate As was avoidance; limiting As transport to shoots and increasing As accumulation in the root system. Arsenic in tomato root tissue seemed to be so effectively compartmentalized that its impact in plant growth and metabolism was minimal. However, in bean plants upon uptake, As was readily transported to shoots and accumulated to high concentrations in leaf tissue. The observed differential absorption and translocation of arsenite or its metabolized species by tomato and bean plants were probably responsible for the different plant tolerance to As pollution. (C) 1997 Elsevier Science B.V.