Résumé:
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.
