Effects of Cadmium on Seed Germination, Coleoptile Growth, and Root Elongation of Six Pulses

The ecotoxicological effects of Cd2+ on germination and early seedling growth of six pulses were investigated. Seeds of these plants were exposed to seven different concentrations of Cd (0, 0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 mM). The results indicated that root and coleoptile growth of six pulse plants were more sensitive than seed germination for measurement of toxic Cd2+ pollution. Different species show different levels of tolerance to Cd2+ pollution. V angularis and Dumasia villosa are the most sensitive to Cd2+, and their germination percentage, and root and coleoptile growth were significantly lower than other tested species. By contrast, Vigna radiata and Lablab purpureus are the most resistant species, their germination and seedling growth almost were not influenced by Cd2+ pollution significantly compared to control. There were significantly negative correlations between seedling growth and increasing concentrations of Cd2+ for V angularis. V angularis and Dumasia villosa are the most sensitive to Cd2+. By contrast, Vigna radiata and Lablab purpureus are the most resistant species.