ARSENIC UPTAKE, DISTRIBUTION, AND ACCUMULATION IN BEAN-PLANTS - EFFECT OF ARSENITE AND SALINITY ON PLANT-GROWTH AND YIELD

The response of bean plants (Phaseolus vulgaris L.) to different level s of arsenic (As) and salinity was investigated, including the process es of uptake, distribution, and accumulation of As and the effect of a rsenite and salinity on plant growth and fruit production. The experim ent was performed in soilless culture at two levels of As: 2 and 5 mg As L-1 [added as sodium arsenite (NaAsO2)], and three saline levels [o nly sodium chloride (NaCl) was added]: 1,000, 2,000, and 4,000 mu S.cm (-1). Arsenic uptake and concentration in root increased upon increase d NaAsO2 concentration in the nutrient solution. However, the increase in the As root content was not proportional to the As level in the nu trient solution. High levels of salinity in solution decreased As upta ke and the concentration of As in root, stem, and leaf. Upon uptake, A s was readily translocated to the aerial organs and approximately half of the absorbed As was transported to the upper parts of the bean pla nts. The As concentration in fruit always remained below the recommend ed limit for As content in fruit and edible vegetal products. While sa linity did not significantly affect plant growth, arsenite was found t o be phytotoxic to the bean plants.