Cadmium-Induced Decrease of Water Stress Resistance in Bush Bean Plants (Phaseolus vulgaris L. cv. Contender) II. Effects of Cd on Endogenous Abscisic Acid Levels

The cadmium content and the endogenous abscisic acid (ABA) levels of roots, stems, primary, and trifoliate leaves of bush bean plants (Phaseolus vulgaris L. cv. Contender), grown with different Cd concentrations in the medium were analysed. The samples were taken at different plant growth stages: primary leaf growth stage, first trifoliate leaf growth stage, flowering, and fruit development. No correlation between Cd and ABA contents could be established. In roots Cd-toxicity increased ABA levels. In leaves only the lowest Cd concentration increased the ABA content, while in plants treated with higher Cd concentrations no increase in ABA content in response to wilting was observed. Cd at high concentrations is suggested to decrease water stress resistance by inhibition of the hydroactive stomata response. © 1986, Gustav Fischer Verlag, Stuttgart. All rights reserved.