Diversity And Ecological Distribution Of Arbuscular Mycorrhizal Fungi From The Rhizosphere Of Avena Sativa In Qinghai Province

AM fungi are the widely distributed soil microbe, which can promote host plant to take up mineral elements from soil, regulate metabolism action inside the host plant, and enhance anti reversibility of plants, and promote plant growth, and increase yield of plants, and improve quality of plants.Avena sativa is an important grain crop and forage crop, it is the main forage to support animal the supplement on Qinghai-Tibet Plateau in cold season. Four Avena sativa plantation areas, including Minhe, Datong, Huangzhong and Haibei in Qinghai Province were selected as the sampling sites. Diversity and distribution of arbuscular mycorrhizal fungi in the rhizoposphere of Avena sativa were investigated in different altitudes and varieties in order to understand the mechanism of symbiont formed by Avena sativa and AM fungi. The research data could provide a theoretical basis and technological support for making full use of arbuscular mycorrhizal fungi resource, accelerate growth of Avena sativa and enhance its production. The main research results are as follows:1. 180 soil samples in the rhizophere of Avena sativa were collected from Qinghai province. Isolation and purification of the AM fungi led to the identification of 31 species in 6 genus, 6 species belonged to Acaulospora, 1 species belonged to Archaespora, 3 species belonged to Diversispora, 1 species belonged to Entrophospora, 1 species belonged Gigaspora, 1 species belonged Scutellospora, 17 species belonged Glomus, 1 species belonged to Pacispora. Two new record species in China: Glomus drummondii and Glomus walkeri and 6 unrecorded sepecies were found from the survey areas. In which, Glomus geosporum was the dominant species.2. The result indicated that good symbiosis was formed between AM fungi and Avena sativa, the diversity of AM fungi in the rhizophere of Avena sativa was rich. The average spore density was 2.51/g soil. Shannon-Weiner index of AM fungi diversiy did not show a vertical distribution pattern. The Shannon-Weiner index in Minhe, the lowest altitude area, was the highest and reached 2.62, which was followed by 2.58 in Datong, 2.1 in Haibei and 1.97 in Huangzhong. Glomus was the dominant genera in different sampling sites, and Diversispora was dominant genera in Huangzhong and Haibei, while only Acaulospora was not the dominant genera in Datong. At the same time, Gigaspora, Scutellospora and Pacispora showed low frequency in four sites.3. The colonization and spatial distribution of AM fungi were influenced by the host plants, geographic environment and soil factors. The NEON's colonization intensity, arbuscule abundance, vesicule abundance, hypha abundance and spore density were higher than other varieties. The colonization intensity, arbuscule abundance, vesicule abundance and hypha abundance at hightest altitude in Haibei was higher than other three sites, and its spore density was significant higher than that in Huangzhong and Minhe. The maximum value of spore density was found in the depth of 0 to 10cm of soil, and the value decreased gradually along with the increasing of soil depth in 0 to 30 cm. It showed an apparent increasing trend after 30cm depth in some sampling sites.4. Different structure colonization intensity of AM fungi showed a positive correlation with soil organic matter and soil available P, a negative correlation with pH value. Spore density showed a positive correlation on the colonization intensity of different structure in the different ecosystem, but no correlation in the same ecosyerem.