Cadmium-Induced Decrease of Water Stress Resistance in Bush Bean Plants ( Phaseolus vulgaris L. cv. Contender) I. Effects of Cd on Water Potential, Relative Water Content, and Cell Wall Elasticity

Abstract

Summary The leaf water potential (ψ w ) and the relative water content (RWC) of primary and first trifoliate leaves of bean plants ( Phaseolus vulgaris L. cv. Contender), grown with different Cd concentrations in the medium, were analysed under both normal water supply and water stress conditions. With these data, Richter plots were drawn, from which the maximum turgor pressure, the turgor loss point, the bulk elastic modulus, and the structure coefficient were derived. Cd generally decreased the water stress tolerance of plants, causing turgor loss at higher RWC and ψ w than in non-treated control plants. Cd increased the bulk elastic modulus and therefore decreased the cell wall elasticity. Low cell wall elasticity seems to be an important causes of the low water stress tolerance in Cd-toxic plants.