Cu-ions mediated changes in growth, chlorophyll and other ion contents in a Cu-tolerantKoeleria splendens

Abstract

The effects of Cu²⁺ on growth, chlorophyll and other ion contents ofKoeleria splendens originated from Cu-contaminated soil have been investigated in nutrient solution. The most evident Cu²⁺ effects concern the root growth, especially the root length. Since in plants grown under lower Cu²⁺ concentrations (4 and 8 μM) root elongation, biomass, chlorophyll, Mg²⁺, Fe²⁺, Ca²⁺ and K⁺ content were increased compared with the control, the development of an adaptive mechanism ofK. splendens to Cu²⁺ is suggested. High Cu²⁺ concentration (160 μM) caused a significant reduction in root length and biomass as well as a decreased rate of chlorophyll biosynthesis. The reduction of growth can be correlated with the toxic effect of Cu²⁺ on photosynthesis, root respiration and protein synthesis in roots. 160 μM Cu²⁺-treatment had a negative influence on the concentrations of Ca²⁺, Fe²⁺, Mg²⁺ and K⁺ and a positive influence on the Cu²⁺ concentration in the plant tissues. Loss of nutrients similar to the senescence response suggests that excess of Cu²⁺ leads to the progressive senescence of the plants. Our results demonstrate the existence of an adaptive mechanism ofK. splendens under low Cu²⁺ concentrations, while high Cu²⁺ quantities cause disturbances in plant function.