The protective role of zinc and calcium in Vicia faba seedlings subjected to cadmium stress

The aim of the present study was to evidence the possible antagonistic effect of Zinc (Zn2+) and Calcium (Ca2+) against cadmium (Cd2+)-induced DNA damage by using random amplification of polymorphic DNA (RAPD) and metabolic activities in Vicia faba. The results showed that all doses of Cd2+ (10(-3) M, 10(-5) M) caused an increase in polymorphism value and a decrease in genomic template stability (GTS %). In addition, when 10(-4)-10(-6) M Ca2+, 10(-6) M Zn2+ were added together with 10(-3) M, 10(-4) M, 10(-5) M of Cd2+, polymorphism value decreased besides GTS, total protein and chlorophyll content increased. Results suggested that Zn2+ and Ca2+ have an antagonistic effect against Cd2+. The order of the antagonisms of Ca2+, Zn2+ against Cd2+ toxicity was Ca2+ > Zn2+. Especially, the degree of antagonistic effect of Zn2+ against Cd2+ is probably related to its concentration ratio.