The Synergistic Interactions Of Selenium (Se) And Molybdenum (Mo) On Growth And Physiological Characteristics Of Chinese Cabbage(Brassica Campestris Lssp,Pekinensis) Under Lead Stress

Ruination of soil resources by heavy metals has become one of the worst nightmares to the environment and public health. Synergistic interactions of heavy metals and elements are very important in remediation of the environment. Se and Mo are known to be antagonists of some heavy metals. A pot experiment was carried out in the greenhouse to investigate the synergistic interactions of Se and Mo, on alleviation of Pb toxicity by Chinese cabbage (Brassica campestris L. ssp. pekinensis) in the soil under three different concentrations of Pb (0,5and50mg·kg-1), Fresh weight and dry weight of Brassica campestris L. ssp. pekinensis was measured. The content of mineral elements in leaf, root and soil were analyzed. Oxidative stress and antioxidant metabolisms of leaf were also investigated and the main results were as follows:1. Low Pb level (Pb5) did not have an apparent effects on physical appearances of the Chinese cabbage, however highest Pb level (Pb50) lead to yellowish and stunted leafs. Biomass in term of fresh and dry weight of Brassica campestris L. ssp. pekinensis was significantly influenced by Pb stress and by application of Se&Mo. Plants in PbO (control) were significantly high in biomass but as Pb level increases to Pb50mg/kg Biomass decreased sharply. Application of Se in PbO significantly decreased biomass however when Pb levels (Pb5and Pb50) increase, Application of Se significantly increased Brassica campestris L. ssp. pekinensis biomass. Mo application increased the Biomass in PbO and decreased biomass in highest Pb level (Pb50). Combination of Se and Mo treatments significantly increased biomass at all Pb levels, and even in the highest Pb50, combination of Se and Mo had significant high biomass.2. Pb content has increased with an increase in application of Pb both in the shoots and roots of Brassica campestris L. ssp. pekinensis. However in Se treatments at all Pb levels (Pb5&Pb50), Se significantly decreased Pb contents. Whereas Mo treatments significantly increased Pb contents at all Pb levels (Pb5&Pb50). The interaction of Se and Mo has also lessen Pb contents in Pb50at a significant level. Control plants (PbO mg/kg) accumulated significant less contents of Pb.3. There is a synergistic interaction between Se and Mo under Pb stress, Mo content significantly decreased as Pb levels increases, and Se was increased by addition of Mo because in all Pb treatments, Se content is apparent in the interaction of Se and Mo. Mo is also an antagonistic to Se, as it also increases Se contents in.4. The highest level of Pb (Pb50mg/kg) generally inhibited the uptake of some of the macro and micro elements when compared to the low level of Pb (0and5mg/kg treatment.(Mg) contents decreased in shoots of Brassica campestris L. ssp. Pekinensis in Pb50treatment. Ca contents in the shoots of Brassica campestris L. ssp. pekinensis increased with an increment in Pb doses, Accumulation of Fe contents in the roots of most of the treatments was just the same at all Pb levels. Se treatment in Pb50increased Zn content in the roots and the increase was significant from the other treatments. Se plays a big role in accumulation of Cu contents in Brassica campestris L. ssp. pekinensis. Mn contents decreased with application of Pb. Se has portrayed some qualities in enhancing the absorption of micro elements in Pb stress environment.5. A significant increment in SOD enzymes activities was detected in the shoots of Brassica campestris L. ssp. pekinensis in the Pb treatments (5and50mg/kg). SOD enzymes was highest in PbOMo, followed by PbOSe then PbOSeMo and lastly PbO. CAT antioxidant enzymes activity increased with an increase in application of Pb. CAT enzymes activities in the shoots of Brassica campestris L. ssp. Pekinensis significantly increased with highest values observed in Pb50SeMo. Pb has significantly decreased the activities of POD. AsA contents in the shoots of Brassica campestris L. ssp. pekinensis increased with an increase in Pb level, with highest contents of AsA observed in Pb50Se (50mg/kg) treatment. AsA content was not stimulated by Mo in PbOMo treatment but AsA reacted significantly in PbOSe and PbOSeMo treatments. GSH contents in the shoots of Brassica campestris L. ssp. pekinensis was enhanced by high level of Pb. GSH content was high in5mg kg and50mg kg Pb treatments, with the highest amount detected in Pb50Se treatments. Se kept antioxidant enzymes activities rising throughout regardless of Pb level...