Effet de l'interaction plomb-salinité sur les réponses morphophysiologiques, biochimiques et biométriques du radis (Raphanus Sativus L.)

Abstract

Lead pollution has become a real threat to our ecosystems, with detrimental effects on crop production and biodiversity. The work begins with a view to studying the morphological, biometric and physio-biochemical behavior of the radish plant (Raphanus sativus L.) in order to approach the impact of salt stress and heavy metals (lead). The plants of the radish (Raphanus sativus L.) are grown under semi-controlled greenhouse for 60 days. Watering was done with distilled water and the nutrient solution. Stress was achieved with the metal solution based on lead nitrate and sodium chloride for six weeks after subculturing at concentrations of :(500 mg / L, 500 + 40 mmol / l, 500 + 80 mmol. , 1000 + 40 mmol / l, 1000 + 80 mmol / l, 2000 mg / L, 2000 + 40 mmol / l, 2000 + 80 mmol / l) , And with saline at concentrations: (40 mmol / l-1; 80 mmol / l-1) relative to a control. After two months of monitoring the crop, the leaves of the plants are torn off in order to carry out the analyzes at the laboratory level. Physiological analysis showed an inhibition of radish growth, foliar and root elongation, masses of fresh and dry matter of different organs of seedlings and radish plants, compared to controls. Biochemical analysis showed a decrease in the content of foliar chlorophyll pigments (chlorophyll a, b, total) and increased carotenoids. Thus, the effect of salt stress on plant growth was analyzed. Our results showed that the different growth parameters studied (the number of leaves and nodes per plant, the length of the stems and roots, the fresh and dry aerial and root biomasses and their respective ratios) vary according to the provenance studied. Indeed, the root part is more sensitive to salt than the aerial part for all provenances tested. In addition, the source of radishes (Raphanus sativus L.) is the most sensitive to salt stress. Thus, radish (Raphanus sativusL.). Under stress has undergone a decrease and an increase in the synthesis of chlorophyll and also decreases in morpho-physiology parameter.