The stress mechanism of zinc on the wheat

To investigate the stress mechanism of zinc on the wheat, different concentrations of zinc were used to treat wheat, and the ultrastructure of mesophyll cells of wheat was observed by transmission electron microscope (TEM). The results showed that at the tillering stage, the number of chloroplast decreased, and the thylakoid of chloroplast of mesophyll cell was disorder at the concentrations of L4 (1,000 mg/kg). At the jointing stage, the volume of chloroplast of mesophyll cell expanded at the concentrations of L4 (1,000 mg/kg). At the mature stage, under low concentrations of L1 (250 mg/kg), some chloroplast of mesophyll cell disappeared or broke, the number of mitochondrion increased, the cell wall was damaged; and under concentrations of L4 (1,000 mg/kg), the cell wall of mesophyll cell seriously fractured, the cell structure was not intact, the number of chloroplast and mitochondrion decreased significantly, the cytoplasm became turbid. These results showed that the stress of zinc on wheat was significant with the increase of stress concentration and time. If the concentration of Zn reached to a certain extent, cell structure would be destroyed. This is the first report indicating the stress mechanism of zinc on wheat in the view of ultrastructure in whole growth period of wheat.