CU-IONS MEDIATED CHANGES IN GROWTH, CHLOROPHYLL AND OTHER ION CONTENTS IN A CU-TOLERANT KOELERIA-SPLENDENS

The effects of Cu2+ on growth, chlorophyll and other ion contents of K oeleria splendens originated from Cu-contaminated soil have been inves tigated in nutrient solution. The most evident Cu2+ effects concern th e root growth, especially the root length. Since in plants grown under lower Cu2+ concentrations (4 and 8 muM) root elongation, biomass, chl orophyll, Mg2+, Fe2+, Ca2+ and K+ content were increased compared with the control, the development of an adaptive mechanism of K. splendens to Cu2+ is suggested. High Cu2+ concentration (160 muM) caused a sign ificant reduction in root length and biomass as well as a decreased ra te of chlorophyll biosynthesis. The reduction of growth can be correla ted with the toxic effect of Cu2+ on photosynthesis, root respiration and protein synthesis in roots. 160 muM Cu2+-treatment had a negative influence on the concentrations of Ca2+, Fe2+, Mg2+ and K+ and a posit ive influence on the Cu2+ concentration in the plant tissues. Loss of nutrients similar to the senescence response suggests that excess of C u2+ leads to the progressive senescence of the plants. Our results dem onstrate the existence of an adaptive mechanism of K. splendens under low Cu2+ concentrations, while high Cu2+ quantities cause disturbances in plant function.