Combined Effect Of Cadmium And Metsulfuron-Methyl On Wheat(Triticum Aestivum L.)

Cadmium (Cd) is one of the most toxic amongst heavy metals. Cadmium has become one of the widely occurring contaminants in soils due to its significant release into environment via anthropogenic activities. Metsulfuron-methyl (MSM) is a low-application-rate sulfonylurea herbicide. Herbicide is indispensable for crop production. However, substantial usage of herbicide has led to its increasing accumulation in soils and crops.In this study, we performed a series of initial experiment with Cd (II)(0,0.3,0.5,1,5and10mg kg-1) or MSM (0,0.005,0.01,0.02,0.04and0.08mg kg-1), the result showed that both the growth and the content of chlorophyll of wheat were decreased progressively following the treatment with increasing concentrations. The pattern of the content of TBARS was low-high-low. At0.5mg kg-1Cd(Ⅱ) and0.02mg kg-1MSM, the accumulation of TBARS got the maximum value. With the increase of the concentration, the excess damage of the cell could not accumulate more TBARS to against the stress.We analyzed growth, physiological and molecular responses in wheat exposed to0.5mg kg-1Cd(Ⅱ) and0.02mg kg-1MSM. Soils contaminated with Cd and MSM complex caused significantly detrimental effect on wheat growth and physiological process. Combinative treatments with Cd and MSM triggered more severely oxidative damage to plant cells as compared with Cd or MSM single treatment. Compared with the growth parameter, the biochemical and molecular responses of wheat appeared more pronounced to Cd and MSM complex. Also, compared with control, wheat plants exposed to Cd+MSM generated more O2-and H2O2, both of which were shown to be the cause of enhanced activity of several antioxidant enzymes. Native polyacrylamide gel eletrophoresis (SOD, CAT and POD) and molecular response analyses (Cu/Zn-SOD, GST and HO-1) were performed to validate the results indicated above. Our results indicated that joint contamination with Cd and MSM was more toxic to wheat than a single contamination. These sensitive biological parameters can be used as biomarkers monitoring the eco-toxicological process in plants.