Stress Resistance Research Of Endophyte In Wild Festuca L And Their Association

In this study, endophyte resources survey and collection in wild Festuca L. in Xinjiang, Tibet were done, and the endophyte infection plants were used to endophyte isolation, purification, identification, preservation. And the endophytes named N. typhinum and N. starrii isolated from plants in Sichuan, Yunnan, Guizhou were used to do further series studies. The studies including:N. typhinum and N. starrii were transferred to product species of tall fescue to form new association, then new features of new tall fescue-endophyte association were tested by photosynthesis; new seeds of new tall fescue-endophyte association were obtained under artificial cultivation; limiting factors for vegetation restoration of gangue piles were simulated, then the series experiments were done including endophytic fungus N. typhinum, N. starrii under acid stress and salt stress, seeds and seedlings of new tall fescue-endophyte association under acid stress and salt stress, plants of new tall fescue-endophyte association under high temperature stress, drought stress, acid stress and salt stress. Theoretical study and production practice were integrated in this study, which filed the blank of using wild Festuca endophytic fungi in our country, the relationships between tall fescue-endophyte association and enviroment were also discussed, and the results could provide new tools and ideas for for vegetation restoration of gangue piles, which have important theoretical and economic value. The major findings are as follows:1) 7 endophyte infected wild Festuca plants were collected from Xinjiang and Tibet, which were Festuca pratensis Huds.,Festuca rubra L.,Festuca brachyphylla Schult.,Festuca kryloviana Reverd.,Festuca ovina L.,Festuca valesiaca subsp.Sulacta(Hack.)Schinz et R.Keller.,Festuca valesiaca subsp. Pseudovina(Hack.ex Wiesb.)Hegi., and endophyte infection rates were 10% to 95%.2)The relationship between fescue-endophyte association and elevation, aspect, slope position, grass type, soil type, soil composition and other environmental factors were initially revealed. Within elevation 910m-4600m, endophyte infection rates would be high in the condition of good lighting; meadow steppe, desert grassland of medium hill and low hill with soil quality; alpine meadow of alpine and subalpine with debris and gravel soil; the lower of sunny, semi-sunny gentle slope of less than 5 degrees; the lower of sunny, semi-sunny steep slope of more than 15 degrees3) The endophytic fungus isolated from Festuca plants were preliminary identified by traditional morphological method as:N. typhinum in Festuca brachyphylla Schult. from 7 plot, Festuca pratensis Huds. from 10 plot,Festuca ovina L. from 13 and 15 plot; N. starrii in Festuca kryloviana Reverd. from 19 plot.4) Series technology system including collection, detection, isolation, purification, identification, artificial inoculation of endophytic fungi were established.5) Photosynthesis experiment showed that after infecting endophyte N. typhinum, N. starrii, the ability of tall fescue Sun Boy, Eldorado, Tripe A and Millennium to resist high temperature was better than non-infected plants.6) 11 new seeds of tall fescue-endophyte association were acquired, including 4 seeds of tall fescue-N. typhinum association,7 seeds of tall fescue-N. starrii association.7) Acid stress experiment showed that N. typhinum could get normal growth under the conditions of pH value 3.5 to 8.1, and N. starrii could get normal growth under the conditions of pH value 5.8 to 8.1. All of 600nm,56nm,490nm wavelengths could be used to determine the optical density of bacterial suspension. Salt stress experiment showed that N. starrii could grow under the conditions of the salt concentration of 0.1% to 2.8%, and could grow better in 0.36% to 1.73%. But N. typhinum could not grow in all salt treatments.8) Acid stress experiments showed that under the conditions of pH value 2.8 to 8.1, after infecting endophyte N. typhinum, N. starrii, germination potential and germination rate of tall fescue Sun Boy, Eldorado, Tripe A, Millennium seeds, radicle length, germ length, radicle fresh and dry weight, germ fresh and dry weight of tall fescue Sun Boy, Eldorado, Tripe A, Millennium seedlings have significantly increased. Tall fescue seeds infected N. typhinum could adapted better under acid growth environment than the ones infected N. starrii. Salt stress experiments showed that under the conditions of salinity 0.1% to 0.36%, after infecting endophyte N. typhinum, N. starrii, germination potential and germination rate of tall fescue Sun Boy, Eldorado, Tripe A, Millennium seeds, radicle length, germ length of tall fescue Sun Boy, Eldorado, Tripe A, Millennium seedlings have significantly increased. Tall fescue seeds infected N. starrii could adapted better under salt growth environment than the ones infected N. typhinum.9)Plants of new tall fescue-endophyte association high temperature stress and salt stress experiments showed that the abilities to resist high temperature and salt comprehensive assessed by weight measure were:N. starrii infected tall fescue plants> N. typhinum infected tall fescue plants> Free infected tall fescue plants. Plants of new tall fescue-endophyte association drought stress, acid stress experiments showed that the abilities to resist drought and acid comprehensive assessed by weight measure were:N. typhinum infected tall fescue plants> N. starrii infected tall fescue plants> Free infected tall fescue plants.