The Exudation of 14X-Cacodylic Acid from the Roots of Bean Plants and Ash Seedlings

摘要

Bean plants (Phaseolus vulgaris L. var. Black Valentine) and green ash seedlings (Fraxinus pennsylvanica Marsh.) were treated with sublethal concentrations of 14C-cacodylic acid (hydroxydimethylarsine oxide) to determine if cacodylic acid is exuded from the roots of plants. The bean plants were treated with three different concentrations of cacodylic acid in 0.5% (v/v) Tween 20 applied in droplets to each primary leaf. Similarly cacodylic acid/adjuvant mixture was applied to the ash seedlings on each leaf of the pair of leaves at the fourth node above the root cellar. The root exudation of radioactive material increased over the 9- and 16-day sampling periods for the bean plants and ash seedlings, respectively. When plant injury resulted, the exudation rate was inhibited even with an increase in the level of radioactivity applied to the plant. At the termination of the experiment, the nutrient xolugionx were spotted on Whatman 3MM chromatography paper and developed in two solvent systems (2-propanol:H2O, 7:3; 1-propanol:NH4OH, 7:3). The radioactive areas on the chromatograms of the nutrient solution concentrate from both the treated bean plants and ash seedlings closely coincided with the chromatogram of the 14C-cacodylic standard and the co-chromatogram of the nutrient solution-standard mix. Therefore, it would appear that 14C-cacodylic acid is exuded as an unaltered molecule. (Modified author abstract)