Effects Of Epichlo(?) Endophyte On Drought Resistance Of Different Ecotypes Festuca Sinensis

In the present study,endophyte infected?E+?and endophyte free?E-?popultion of six ecotypes Festuca sinensis?ID 41?57?84?99?111 and 141?which collected from Qinghai and Sichuan province were established.The growth,nutrient uptake,ion distribution,photosynthesis,hormones and alkaloids contents of these F.sinensis plants under optimal?65%relative saturation moisture content,RSMC?and drought?35%RSMC?moisture conditions in the greenhouse were analysis to explore the effects and mechanism of Epichlo?endophyte and host ecotypes on drought resistance of F.sinensie.The main results showed as follows:1.The host ecotypes had significant effects on the growth of plants.Under both optimal and drought moisture conditions,there were significant differences between six ecotypes E+plants and between six ecotypes E-plants?P<0.05?.Drought stress significantly inhibited the plants growth.For example,compared with the optimal moisture conditions,the tiller number of ecotype 99E+plants,the above-ground part fresh weight and dry weight of the ecotypes 111 and 141E+and E-plants,the root fresh weight and dry weight of the eco types 41,57 and 141E+and E-plants significantly decreased under drought stress?P<0.05?.Endophyte improved the growth of host plants under optimal moisture conditions,the plants height,tillers number,fresh weight and dry weight content of six ecotypes E+plants were significantly higher than those of the corresponding E-plants?P<0.05?;endophyte also improved the drought stress tolerance of host plants,and some growth indices of six ecotypes E+plants were significantly higher than those of the corresponding E-plants?P<0.05?.2.The contents of photosynthesis,chlorophyll and endogenous hormone and stomatal characteristics of six F.sinensis ecotypes E+and E-plants under different moisture conditions were also different.Host ecotypes had significant effects on these indices?P<0.05?.For photosynthesis,stomatal characteristics and endogenous hormones under both optimal and drought moisture conditions,there were significant differences between some ecotypes E+plants and and between some ecotypes E-plants.Drought stress significantly inhibited photosynthesis,decreased chlorophyll and hormone content and stomatal aperture,significantly increased stomatal density of some ecotypes plants.For example,compared with optimal moisture conditions,stomatal conductance and transpiration rate of E+and E-plants of ecotypes 41,84,111 and 141,chlorophyll content of E+and E-plants of ecotypes 41 and 57,CTK contents of E+plants of ecotype 111 and stomatal aperture of adaxial epidermis of E+and E-plants of ecotypes 99?111?141 significantly decreased under drought stress?P<0.05?.Under both optimal and drought moisture conditions,endophyte had significant effects on these indices of host plants?P<0.05?.For example,under drought stress,the net photosynthetic rates of ecotypes 41 and 111E+plants,the stomatal conductance of ecotype 99E+plants,and the intercellular carbon dioxide concentration and transpiration rate of ecotypes 41,99,and 111E+plants were significantly higher than those of the corresponding E-plants?P<0.05?.The chlorophyll contents,stomatal density,stomatal aperture,ABA,CTK and GA contents of E+plants of some ecotypes were significantly higher than the those of the corresponding E-plants?P<0.05?.3.The contents of C,N,P and Na⁺,K⁺,Ca²⁺of six ecotypes of F.sinensis E+and E-plants were different.Host ecotypes had significant effects on these indices?P<0.05?.Under both optimal and drought moisture conditions,the contents of C,N,P and Na⁺,K⁺,Ca²⁺have significant differences between some ecotypes E+plants and between some ecotypes E-plants.Drought stress significantly reduced the C,N,P and Ca²⁺contents of plants,and significantly increased the K⁺contents.For example,compared with the optimal moisture conditions,the root C contents of ecotype 111E+plants,the above-ground part N contents of ecotype 84E+plants,the root N contents of ecotype 57E+and E-plants,the above-ground part P contents of ecotype 111E+and E-plants,and the Ca²⁺contents of ecotypes 84E+and 111E-plants significantly decreased under drought stress?P<0.05?,whereas the K⁺contents of ecotypes 99 and 111E-plants significantly increased under drought stress?P<0.05?.Under both the optimal and drought moisture conditions,endophyte had significantly effectes on these indices of host plants?P<0.05?.For example,under drought stress,the above-ground part P and Ca²⁺contents of the ecotype 111E+plants were significantly higher than those of the 111E-plants?P<0.05?.The Na⁺and K⁺contents of the ecotype 111E+plants were significantly lower than those of the 111E–plants?P<0.05?.4.The contents of lolitrem B,peramine,ergine and ergonovine in six ecotypes of F.sinensis E+plants were significantly different under both optimal and drought moisture conditions?P<0.05?.Alkaloids contens of some ecotypes were significantly higher than those of the other ecotypes?P<0.05?.Soil moisture conditions had no effects on peramine contents,but had significant effects on lolitrem B and ergot alkaloid contents?P<0.05?.Compared with optimal moisture conditions,drought stress significantly improved lolitrem B and ergot alkaloid contents of some ecotypes?P<0.05?.For example,the ergine and ergonovine contents of ecotypes 57,84 and 99 plants under drought stress were significantly higher than those of these ecotypes under the optimal moisture conditions?P<0.05?.In summary,drought stress affects plant growth and physiological and biochemical response,the drought resistance of ecotype 141 is superior to the other four ecotypes which can be used for the further drought-resistant breeding.When endophye associated with the ecotypes 111 and 57,the drought resistance of the host is better than other ecotypes which suggesting these 2 endophyte strains can be used for drought-resistant breeding.The physiological and biochemical responses revealed that endophyte increase the host drought resistance by promoting photosynthesis,increasing stomatal density and ion contents.