Physiological and ultrastructural changes in Arabidopsis thaliana as affected by changed GSH level and Cu excess

We investigated the responses of wild-type Arabidopsis thaliana plants to the excess of Cu under conditions of the changed intracellular level of reduced glutathione (GSH) after application of buthionine sulfoximine (BSO) or exogenous GSH to the nutrient solution. BSO (500 A mu M) decreased and exogenous GSH (500 A mu M) increased GSH level, while increasing Cu concentration (from 5 to 50 A mu M) resulted in a decreased GSH content in the roots, but in its increased content in the shoots. BSO did not affect plant growth in contrast to exogenous GSH and Cu, which significantly reduced plant fresh weight. Both Cu and BSO or GSH induced changes in the root structure and leaf chloroplasts ultrastructure. Cu did not induce phytochelatin accumulation. Application of BSO or exogenous GSH did not significantly affect either the GSH level in the Cu-treated plants (except for 50/50 and 50/500 A mu M/A mu M Cu/GSH treatments increasing intracellular GSH content in the roots) or Cu toxicity to plants. These results suggest that GSH is not directly involved in Cu detoxification and tolerance in A. thaliana, yet it influences the proper anatomical structure of plants.