我国北方农田土壤中AM真菌的多样性

AM真菌是农业生态系中一类重要的土壤微生物，它在农田土壤中的发生和分布受多种环境因素的影响。为深入了解我国北方农田土壤中AM真菌的多样性规律，于2000年在河北、山东的农田土壤中采集有代表性的土样127个。通过进一步扩繁、纯化，从中分离出AM真菌5属22种，鉴定了20个种，包括一个国内新记录种沾屑球囊霉(Glomus spurcum)。分析AM真菌的多样性特点及其影响因素发现，农田土壤中以球囊霉属(Glomus)的频度最高，其次为无梗囊霉属(Acaulospora)；优势种类为幼套球囊霉(Glomus etunicatum)和摩西球囊霉(Glomus mosseae).土壤速效磷含量、pH状况主要对孢子密度产生影响，对种群分布影响不大。宿主植物类型对AM真菌的侵染状况和多样性影响较大；比较玉米(Zea mays)、甘薯(Ipomoea batatas)根区AM真菌的种群组成后发现两者有所不同，但优势种一致.

Diversity of arbuscular mycorrhizal fungi in field soils from North China

Arbuscular mycorrhizal (AM) fungi are important soil microorganisms in agroecosystems. Biodiversity among AM fungi in crop fields is influenced by many factors, including soil properties and plant species. In order to study AM fungal diversity in field soil of North China, we collected 127 soil samples from various crop fields from Shandong and Hebei provinces. Culture and purification of the mycorrhizal fungi led to the isolation of 22 species in five genera. Among these, 20 species were identified, including a new record for China, Glomus spurcum Pfeiffer, Walker & Bloss. The frequency of occurrence of the genus Glomus was the highest and Acaulospora was the second most common genus, while Glomus etunicatum and G. mosseae were dominant species. Spore density was affected by soil Olsen-P content and pH, while species diversity was little affected. Moreover, AM fungi species colonization and diversity was greatly affected by host plants. Although AM fungi hosted by maize and sweet potato had similar dominant species, there were differences in species composition.