Phyto-extraction du plomb par le radis (Raphanus sativus L.)

Abstract

Nowadays, the soil pollution is one of the most sensitive environmental problems and often the phytoremediation is associated with him as process of decontamination. With respect to this, the present work, realized in the laboratory "biodiversity and preservation of waters and soils"/University of Mostaganem, was focused on the stress effects of the lead on plants. The objective was to determinate the accumulation potential of lead by the radish (Raphanus sativus L.) and to find out how is its capacity of soil decontamination. The radish plant was exposed to various lead concentrations (0, 500, 1000 and on 2000 ppm). The experiment ex situ was undertaken during two months, including the seeding and the growth of the radish. The biometric analysis after the exposure to lead showed an inhibition of the top of the plant and the roots, and in the weight of fresh substance and dry one of different parts of the radish with regard to the reference sample. The water content analysis of the exposed plants to lead showed an increase of the relative water content (RWC) compared with the reference sample while the loss of water by transpiration (RWL) decreases. The physiological analysis showed a decrease of the content in foliar chlorophylls’ pigments (chlorophyll a, b and total) and contents in carotenoids of the radish exposed to lead with different concentrations, compared with the reference sample. The investigation results show that lead causes a stress on the radish (Raphanus sativus L.) during its growth, but this plant possesses mechanisms of protection allowing it a certain tolerance to lead excess. This plant can be used in a system of soil remediation because it possesses particular properties of natural resistance with several abiotical constraints.