Uptake, Accumulation, and Translocation of Arsenical Compounds by Cotton

Abstract

AbstractUptake, accumulation, and translocation of arsenic from different arsenical compounds were investigated in cotton plants (Gossypium hirsutum L. ‘SJ‐4’). Cotton plants grown in solution culture were exposed to arsenic trioxide (As2O3) from 0 to 8 µg As mL−1. Arsenic was readily taken up by the roots but was not translocated to the shoots. In contrast, when cacodylic acid (hydroxydimethylarsine oxide; (CH3)2As(O)OH) was applied in the range of 0–40 µg As mL−1, As was found not only in the roots but also in the leaves and reproductive structures. Plants treated with the herbicides MSMA (monosodium methanearsonate) and DSMA (disodium methanearsonate) also accumulated As in the roots and shoots. The defoliant, cacodylic acid, was applied as a foliar spray at the commercially recommendated rate of 1.4 kg/ha of cacodylic acid equivalents to cotton plants with green and mature bolls. Cottonseed from the treated bolls did not accumulae As above 2.6 µg As g−1, the tolerance limit. However, at higher application rates, the As concentrations increased in the cottonseed.Cotton plants grown in the greenhouse in Yolo clay loam (fine silty, mixed, nonacidic, thermic Typic Xerorthents) with a soil background level of 6 µg As g−1, were grown with cotton‐gin trash containing cacodylic acid at 0 to 53.5 µg As g−1 mixed into the soil. Analyzed plant samples contained < 0.05 µg As g−1 and did not accumulate or concentrate arsenic from the soil.