调查了都江堰地区3个不同生境样地（般若寺、馒头山、龙池）中85种优势及常见植物的丛枝菌根真菌侵染率，其中78种植物（91.8%）被丛枝菌根真菌侵染。同时对其中58种植物根围土壤中丛枝菌根真菌的多样性进行分析，共分离到5属47种丛枝菌根真菌，其中球囊霉属（Glomus）35种，无梗囊霉属（Acaulospora）7种，原囊霉属（Archaeospora）1种，内养囊霉属（Entrophospora）2种，巨孢囊霉属（Gigaspora）2种。无梗囊霉属和球囊霉属是3个样地共有的优势属。光壁无梗囊霉（Acaulospora laevis）是龙池的优势种，而地表球囊霉（Glomus versiforme）是般若寺和馒头山的优势种。丛枝菌根真菌的孢子密度和种的丰度显著受到海拔相关因子影响，同时丛枝菌根真菌的种类组成也受较大影响。乔木砍伐没有显著影响丛枝菌根真菌的孢子密度和种的丰度，同时对种类组成影响也较小。根围土壤中丛枝菌根真菌的孢子密度与根系侵染率之间没有显著相关性（R2=0.024 8）。
Arbuscular mycorrhizal fungi (AMF) form mutualistic symbiotic associations with the roots of approximately 80% of terrestrial plant species. AMF are an important component of ecosystems, and the diversity of the AMF could largely influence plant biodiversity, ecosystem variability and productivity. Dujiangyan, located in the upper reaches of the Yangtze River in subtropical region of Sichuan province in southwest China with a complex geographic environment, is rich in biodiversity. To investigate the effect of environmental factors, particularly altitude-related factors and disturbance, on AMF diversity, a survey of the diversity and ecology of AMF was carried out in Dujiangyan in August 2001.Three sampling sites were selected in the present study, which represented different habitats: Banruosi, the natural evergreen broadleaved forest; Longchi, the natural subalpine forest; and Mantoushan, a seriously disturbed site, in which all woody plants were cut about 20 years ago and annuals were dominant. A total of 85 common plant species were chosen, of which 51 plant species were sampled from Banruosi, 19 from Mantoushan, and 19 from Longchi (some species were simultaneously collected from the different sites). Of the 85 plants, 51 species belong to the angiosperms, 31 belong to the pteridophytes, and 3 belong to the Gymnosperms. Roots collected from each plant were cleaned and preserved in 50% ethanol. The percentage of root length colonized by AMF was quantified according to the magnified line-intersect method. Concurrently with root sample collection, a total of 58 rhizosphere soil samples were collected, of which 30, 16, and 12 were sampled from Banruosi, Longchi and Mantoushan, respectively. The soil samples were placed in sterilized cotton-cloth bags, labeled, and air-dried in shade for one week. The soils were cleaned, ground, sieved with a 2 mm sieve, stored at 4 ℃, and processed within three months. AMF spores were isolated from 100 g air-dried soil from each sample using the wet-sieving and decanting method.Seventy-eight (91.8%) out of 85 plant species examined were colonized by AMF; this group included 49 (96.1%) out of 51 angiosperms, 26 (83.9%) out of 31 pteridophytes, and 3 (100%) out of 3 gymnosperms. In total, 47 taxa of AMF belonging to 5 genera were isolated from the 58 soil samples, of which 35, 31, and 9 taxa were found in Banruosi, Mantoushan and Longchi, respectively. Thirty-two (68%) taxa were identified at species level, and the other 15 (32%) taxa were identified at genus level. In the 47 taxa, 35 belonged to the genus Glomus, 7 to Acaulospora, 1 to Archaeospora, 2 to Entrophospora, and 2 to Gigaspora. Acaulospora and Glomus both were the dominant genera in the three sites. Acaulospora laevis was the dominant species in Longchi, and Glomus versiforme was the dominant species in Banruosi and Mantoushan. There were no significant differences in spore density or species richness between Banruosi and Mantoushan, while they were significantly higher in Banruosi and Mantoushan than in Longchi. The highest AMF diversity index occurred in Banruosi (2.66), followed by Mantoushan (1.96) and Longchi (1.71). There was no significant correlation between the spore density and the percentage of root length colonized by AMF based on the analysis of linear regression (R2=0.024 8). It could be concluded that the species composition of AMF was greatly influenced by altitude-related factors, but lightly influenced by deforestation.
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