effects ofmetal toxicity on growth and pigment contents ofannual halophyte (a. hortensis and a. rosea)

the toxicity of four potentially toxic trace elements (cu, ni, pb and zn) to annual atriplex (a.hortensis and a. rosea) was examined to determine if this plant showed sufficient tolerance to be used tophytoremediate soils polluted with these heavy metals. the soils, which contained up to (per kilogram) 501mg cu, 1674 mg ni, 1334 mg pb and 3588 mg of zn were sampled around metal-contaminated site insouthwest of france. we submit therefore that it could be that the presence of some heavy metals accumulatedin the plants may have reached toxic levels thereby causing inhibition to their growth and pigment contents.the plant growth expressed as shoot and root dry weight of atriplex plant was adversely inhibited whenexposed to high concentrations of polluted soil. significant increases in chlorophyll content were observed inleaves for three atriplex varieties after the plants were exposed to stress treatments. the carotenoid andanthocyanin content also decreased. red variety of atriplex accumulated more anthocyanins in leaves thangreen and rosea ones. the lipid peroxidation increased, considerably at 100% polluted soil, which is a typicalplant reaction to the oxidative stress. we proposed for the reduction state of photosynthetic parameters to bea useful tool in bioassay toxicity testing of metal polluted soil. these results demonstrate that heavy metalcontamination of soil has adversely affected the photosynthetic parameters of annual atriplex. the presentstudy shows that exposure to heavy metals induced oxidative stress which was accompanied by growthinhibition, enhanced lipid peroxidation levels, increase content of chlorophyll, decrease content of carotenoidsand anthocyanins. finally, it was concluded that annual atriplex has a high ability to tolerate cu, ni, pb andzn, so it might be a promising plant to be used for phytostabilization of metal contaminated soil.