Toxicity of Copper, Cadmium, Nickel, Lead and Zinc on Seed Germination and Seedling Growth in Eruca Sativa

Abstract

In this study, the effects of varying concentrations of Cd, Cu, Ni, Pb and Zn on seed germination, as well as root and hypocotyl length were determined. The inhibitory effects of these metals on germination or roots and/or hypocotyl lenght were different. Cadmium, lead and zinc were not very toxic for germination. However, it has been found that copper was the most inhibitory metal influencing germination, root and hypocotyl growth. Even very low concentrations (25 μg ml-1) inhibited the growth of root and hypocotyl. The seeds of E. sativa germinated at the highest Zn concentrations (1500-2000 μg.ml-1 Zn), whereas roots and hypocotyls prolonged only till 1000 μg.ml-1 level. The seeds of E. sativa in stages of germination and early growth were generally tolerant to zinc, but the results of this study indicated that growth of roots and hypocotyls was more sensitive to heavy metals (Cd, Cu, Ni, Pb and Zn) than that of the stage of germination.