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

The nature of copper (Cu) toxicity on the growth, and pigment, and ele ment composition of a Cu-tolerant ecotype of Silene compacta Fischer w as investigated in nutrient solution. The most evident Cu effect was o n root growth. Since for plants grown under lower Cu concentrations (4 and 8 mu M), root elongation, and chlorophyll, and elemental [Cu, iro n (Fe), calcium (Ca), and potassium (K)] contents were increased as co mpared to that of the control, the development of an adaptive mechanis m 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 si gnificant chlorophyll loss, Yet at the 160 mu M Cu-treatment, changes in elemental content of the plant tissues were observed. External Cu h ad a negative influence on the concentration of Ca, Fe, and K and a po sitive influence on the Cu concentration in the plant tissues. Our res ults demonstrate the existence of an adaptive mechanism of Silene comp actoc at low Cu concentrations, but when at excessive quantities, resu lts in severe injury to plant functions.