Potential of halophytic plant Atriplex hortensis for phytoremediation of metal-contaminated soils in the mine of Tamra

Abstract

ABSTRACT Contamination by metals from anthropogenic activities has significant consequences for ecosystems and human health. Indeed, these elements, by nature are non-biodegradable, have a high ecotoxicity, and could be involved in many pathologies. The genus Atriplex is well adapted to extreme environmental conditions and exhibits heavy metal accumulation properties. This study aimed to examine the response of halophytic plant (Atriplex hortensis) in soil polluted with toxic elements. To address this, we measured plant growth parameters, chlorophyll fluorescence parameters of optimal (Fv/Fm), PSII quantum yield (ϕPSII), and stomatal conductance (gS). By applying this metallic stress to the A. hortensis plant during 2 months of growth, morphological analyses show no reduction in the leaf area, elongation of the stems and roots, and dry matter compared to controls grown on sand. Biochemical and physiological analyses show a slight decrease in the content of foliar chlorophyll pigments (chlorophyll total) and carotenoids as a function of time in soil contaminated with heavy metals. In these experiments, we investigated the photosynthetic rate and chlorophyll fluorescence parameters; the results indicated that on polluted and sandy soil, the values of chlorophyll fluorescence parameters of optimal (Fv/Fm), effective quantum yield of photosystem II photochemistry (ϕPSII) and stomatal conductance (gS) have no significant difference. The results obtained in our study show that A. hortensis can grow in environments heavily polluted by metals, such as zinc, lead, and cadmium. As a result, the cultivation of these species, often recommended for the phytostabilization of sites polluted by metals, could be established. The results obtained are in favor of the involvement of Atriplex hortensis in a phytoremediation project to clean up contaminated soils.