ROOT-GROWTH AND PIGMENT COMPOSITION IN RELATIONSHIP TO ELEMENT UPTAKE IN SILENE COMPACTA PLANTS TREATED WITH COPPER

The nature of copper (Cu) toxicity on the growth, and pigment, and element composition of a Cu-tolerant ecotype of Silene compacta Fischer was investigated in nutrient solution. The most evident Cu effect was on root growth. Since for plants grown under lower Cu concentrations (4 and 8 mu M), root elongation, and chlorophyll, and elemental [Cu, iron (Fe), calcium (Ca), and potassium (K)] contents were increased as compared to that of the control, the development of an adaptive mechanism by S. compacta to Cu is suggested. Higher Cu concentrations (80 and 160 mu M) resulted in a significant reduction in root growth and an significant chlorophyll loss, Yet at the 160 mu M Cu-treatment, changes in elemental content of the plant tissues were observed. External Cu had a negative influence on the concentration of Ca, Fe, and K and a positive influence on the Cu concentration in the plant tissues. Our results demonstrate the existence of an adaptive mechanism of Silene compactoc at low Cu concentrations, but when at excessive quantities, results in severe injury to plant functions.