Genetic Diversity Of Drunken Horse Grass (Achnatherum Inebrians) And Effects Of Its Endophyte Infection On Cold Tolerance

Drunken horse grass (Achnatherum inebrians), an intoxicating and conservation of water and soil grass growing at native grassland in Northwestern China, symbiotic with endophyte of Neotyphodium gansuense was studied, mainly including polymorphic microsatellite loci development, analysis of the genetic diversity and effects of endophyte infection on cold tolerance to drunken horse grass. The results summarized as followings:1. Based on the experiment of different low temperature stress, we documented that endophyte could increase the germination rate, accelerate germination speed and promote growth of radicle and embryo of A. inebrians seeds collected from Xiahe, Gansu, China. Especially under 10℃stress, the germination rate, germination index and length of radicle and embryo of endophyte infected (E+) plants of drunk house grass were significantly higher than those of endophyte free (E-) plants (p<0.05).2. Based on the growth experiment of long term low temperature stresses, the result indicated that endophyte could obviously promote underground biomass accumulation of E+seedlings(p<0.05), increase or maintain above-ground biomass and induce redistribution of biomass pattern which increased root /shoot ratio and improved ability of cold tolerance.3. Based on the growth experiment of short term low temperature stresses, the result showed that the osmoregulation system, membrane system and photosynthetic system of A. inebrians were damaged in various degrees. Under 5℃stress, compared with the E-seedlings, the E+ seedlings obtained high levels of soluble protein content, sugar content, SOD,CAT activity and maximal photochemical efficiency of PSII (p<0.05), performed strong chilling tolerance.4. The result of the over-wintering experiment of A. inebrians plants showed that endopyte could enhance the winter survival rate and spring re-growth capability of E+ plants.5. Twelve microsatellite markers were developed for A. inebrians using the magic-beads, we documented that 90 % of that 12 primers could be used in study of genetics diversity of other species of Achnatherum.6. Six microsatellite loci were used to analyze the genetic diversity of 80 individual plants of A. inebrians from eight populations. The result indicated that rich genetic diversity among A. inebrians could be revealed by SSR marker, performed higher genetic differentiation. Based on the UPGMA cluster analysis and PCA, the 8 A. inebrians populationis investigated could be divided into two groups, i.e.: Xinjiang group and Gansu-Ningxia-Qinghai group. There was a significant (p<0.05) correlation between genetic distance and geographic distance among A. inebrians in the research.