Study on the effects of heavy metals on seed germination and plant growth on Jatropha curcas

Abstract

The individual effects of several doses of Cd, Cr, Zn, Cu, Pb and Hg on seed germination and growth of Jatropha curcas was studied. The doses used in this study were 1, 10, 20, and 30 mM. The seed germination and plant growth was significantly affected by Cd, Cr, Pb and Hg at 10 mM, as well as by Cu and Zn at 20 mM and higher concentrations (P<0.05). At lower concentration, Zn did not affect seed germination. The roots of the plants exposed to 1 mM-dose of Cd and Cu and 1 and 10 mM-dose of Zn grew more than the roots of the control treatment; on the other hand, for all the treatments of Cr, Pb and Hg, root length was significantly decreased. Exposures of 1 mM of Cd, Cr, Pb and Hg reduced the shoot length as compared to the control, while Cu and Zn increased the shoot length by 21.1 and 29.5% respectively.