Plant Metal Interaction PDF Download

Two experiments were conducted in an attempt to identify suitable candidates for the remediation of saline metal-polluted environments. Percent germination and speed of germination of the glycophyte H. vulgare and the halophytes P. coronopus and P. oleracea were evaluated at three salinity levels (0, 9, 18 dS/m) and 4 metals (no metal, 2 ppm Cd, 4 ppm Cr and 10 ppm Ni). While Cd and Cr stimulated the germination of P. coronopus at 9 dS/m, all metals decreased the speed of germination of//, vulgare at 18 dS/m. Both P. coronopus and P. oleracea had no germination at 18 dS/m, and their speed of germination decreased with increasing salinity. This was attributed to osmotically induced dormancy, triggered by salinity stress.--The salt-tolerant plants H. vulgare, I. crithmoides, P. coronopus and P. oleracea, were grown in a greenhouse at three salinity levels (0, 9, 18 dS/m) and four metals (no metal, 2 ppm Cd, 4ppm Cr, 10 ppm Ni), to evaluate the combined effects of metal and salinity on plant metal uptake While H. vulgare, I. crithmoides and P. coronopus were tolerant to both salinity and metal, growth of P. oleracea was reduced at 18 dS/m Growth of P. oleracea was also affected by Cd and Ni treatments. Therefore, it appears that tolerance thresholds of P. oleracea for Cd and Ni are below 2 ppm and 10 ppm respectively. Since metals decreased Na accumulation in plants, it might be speculated that metals induce a physiological change at the level of root permeability, thus affecting Na uptake by plants--None of the plants accumulated significant amounts of metals. Metal uptake was affected by salinity as decreases in Cd, Cr and Ni uptake were observed with increasing salinity. The restriction of Na uptake beyond a certain salinity level in the environment might reduce the concurrent uptake of metals such as Cd, Cr and Ni. Consequently, reduced metal uptake occuring with high salinity stress questions the use of salt-tolerant plants for phytoremediation.