Study Of Plant Endophytic Fungi GY1-1 On Rice Resistance Under Cd Or/and Na Cl Stress

The heavy metal cadmium(Cd)and soil salinization is one of the important factors that restrict our country grain output.Rice is the main food crop.It is a pressing problem to reduce the damage of heavy metals and salt on rice.Endophytic fungi Gao Y1-1 isolated from alkaline infected Liaoxing 1 rice seeds.First,different concentrations of fermentation broth(0,5 %,10%,10%,15%,25%)was used to screen the optimal concentration.Then the rice was divided into two groups-the endophytic fungi infected group(E+)and the Endophytic fungi non-infected group(E-).50 ?M CdCl2 and/or100 mM NaCl was used to treat rice seedlings as single duress and joint stress.The growth of rice seedling index,photosynthetic pigment,antioxidant system and the trend of the change of osmotic regulation substances content were determined to analyze effect of endophytic fungion on rice resistance under Cd or/and NaCl stress.The main results were as follows:1.In the seed period,the optimum concentrations of fermentation broth was 10% on promoting the growth of rice.2.The height and root length of rice seedlings are smaller than the control under Cd and NaCl stress;Theprocess rice seedlings,The height of E+ treated plant was significantly higher than E-under Cd or NaCl stress.The root length of E+ treated plant was significantly higher than E-under Cd and NaCl stress.3.Chlorophyll a and b contents of E+ treated plant were significantly higher than E-;The carotenoid content of E+ treated plant was higher than that of E-;4.The SOD,CAT and POD activity of rice seedlings were significantly reduced without endophytic fungi under Cd and/or NaCl stress.The SOD,CAT and POD activity of E+ treated plant were higher than that of E-.5.The proline content of the rice seedlings were elevated under Cd and/or NaCl stress.While soluble sugars and soluble protein content were decreased.With the increase of rice growth time,the proline content and soluble protein content of rice seedlings were increased gradually.The soluble sugar content was gradually decreased.The proline content of E+ treated plant was lower than E-,while soluble sugar and soluble protein content were greater than E-;5.Hyperoxide anion content,peroxide contentwere and MDA content were increased under Cd and/or NaCl stress.Hyperoxide anion content,peroxide contentwere and MDA content of E+ treated plant were lower than those of E-.With the increase of time,the content of rice seedlings superoxide,hydrogen peroxide and propylene glydehyde were gradually increased;...