Arbuscular Mycorrhizal Fungi In Cultivated Soil From Sichuan Province

Arbuscular mycorrhizal (AM) fungi are important soil microorganisms in agroecosystems by enhancing host plant survival and growth. The objectives of this study were to investigate the germplasm of AM fungi, to understand the distribution patern of AM fungi in diferent ecological conditions such as area, soil factor and host plant, to select isolates effective in nutrient acquisition in this aera, and to monitor AMF after their introduction into the field.1. ARBUSCULAR MYCORRHIZAL FUNGI IN CULTIVATED SOIL FROM SICHUANThe vesicular arbuscular myccorhizal status and the vesicular arbuscular mycorrhizal fungi in the cultivated soil of Sichuan province were investigated. 50 soil samples were collected from fields in which various crop plants were grown . The soil pH and phosphorus contents were detected, and the distribution characters of AMF in these soil were studied. The results revealed that the average natural infection ratio of the individual plant of the main crops (wheat and maize) was 12.1% in this area. Using VA mycorrhized breading technique, the individual plant infection frequency could be attained to 100%. So the application of mycorrhized breading technique has a large gap in this area. At the same time, the naturally formed VA mycorrhiza in this area also means that the area was a natural ecological distribution inhabit for AMF. The natural infection intensity was relatively low in the two crops and the combination of the crops and AMF was still waiting for to be optimized. In the investigated areas, the natural infection frequency of maize was relatively high, and both crops have relatively strong infection intensity in the purple soil. So, the purple soil maybe the ideal places for screening high efficiency AMF strains in the future.The pH of the cultivated soil in Sichuan area is between 5 and 7, this is an essential situation for AMF. At the same time, both host plant could mycorhized with AMF in a variety range of available phosphorus, and this is also a very advantage condition for the application of AMF in this area. But available phosphorus in these soil samples was relatively high, maybe a factor which result in a low infectionintensity of the two crops in this area.311 specimen of spores or sporocarps of AMF were wet sieved from the collection of the rhizosphere soils. Only 18 species of AMF were isolated from these fields.Among these 18 species AMF, 13 species belong to Glomus, 2 species belong to Acaulospora, and 3 belongs to Scutellospora. Gl.mosseae, Gl.caledonium, Gl.constrictum had a wide distribution, and its species frequency was more than 10%. They were dominant species in the area. AMF were found at all 50 sampling sites, at average 305 infective propagales per lOOg dry weight of soil (for 95% probability). The infective propagales in the maize rhizosphere soil in was higher than other plants, and the infective propagales in the purple soil was of the highest.2. PRIMARY STUDY ON ARBUSCULAR MYCORRHIZAL FUNGI OF VEGETABLE LEGUMES FROM PANXI REGIONArbuscular mycorrhizal fungi (AMF) were investigated in vegetable Legumes throughout Panxi region of Sichuan province. The spores of arbusular mycorrhizal fungi were isolated with centrifugation-sugar flotation, and identified based on the morphological characters. They were found at 21 sampling sites, and belong to A.delicata, G.luteum, G.mosseae, G.aggregatum, G.lamellosum, G.claroideum, G.etunicatum, G.intraradices, G.occultum. The infect of arbuscular mycorrhizal was very well.