Influence of Cadmium on Growth and photosynthesis of Atriplex halimus L.

Abstract

Heavy metals contamination of soil is a serious problem in recent times due to threat to plant growth, soil quality, animal and human health. However, the phytoremediation is a cost-effective and environment-friendly strategy for decontaminating heavy-metal-contaminated soil. Use of halophyte plant, Atriplex halimus L. for heavy metal remediation is of particular interest since this plant is naturally present in soils characterized by excess of toxic ions. In the present study, A. halimus was grown in hydroponic conditions to investigate the effect of cadmium chloride (CdCl2.5H2O) on growth, photosynthesis and Cd accumulation. Treatments were prepared by adding (0, 50, 250 and 500 μM) to the nutrient medium. The plants from the study species showed the ability to survive and grow under Cd concentrations of up to 500 μM. Although, concentrations of 50 μM and higher caused a decrease in growth and photosynthesis. Moreover, Cadmium induces a number of physiological changes, such as growth and photosynthesis inhibition. Therefore, a significant reduction in biomass production, the contents of Chl a, Chl b and Carotenoids were observed in Cd treated plants compared with the control plants. Whereas, the Translocation Factor were proportional to the initial concentration of metal in the growth medium. However, the low transfer of Cd from solution to above-ground organs at higher solution metal concentrations indicates an exclusion mechanism. Hence, A. halimus showed an intermediate level of tolerance according to the imposed treatments. The outcome of this study corroborate that the Atriplex halimus is a suitable candidate for the phytoremediation of Cadmium contaminated soil.