CHROMIUM TOXICITY IN SALVIA-SCLAREA .1. EFFECTS OF HEXAVALENT CHROMIUM ON SEED-GERMINATION AND SEEDLING DEVELOPMENT

Seeds and seedlings of Salvia sclarea L were treated with different concentrations of hexavalent chromium (as K2Cr2O7). In vitro seed germination was not affected but when the emergent radicle came into contact with the Cr solution, its growth was inhibited although early shoots and cotyledons developed normally. If the seedlings were transferred to Eppendorf vials so that the roots were completely immersed in the Cr solution, not only root elongation, but also shoot and cotyledon development were inhibited. After 48 hr cotyledons appeared chlorotic, chlorophyll and carotenoid contents were reduced, but chloroplast ultrastructure was normal. The only ultrastructural alteration was a partial detachment of the plasma membrane from the cell wall.