中文摘要：

2006年5、8和10月分别从陕西榆林沙生植物园样地油蒿（Artemisia ordosica）根围分0～10、10～20、20～30、30～40和40～50cm5个土层采集土壤样品,系统研究了AM真菌的时空分布。结果表明,AM真菌孢子密度和丛枝定殖率随时间呈递减趋势;泡囊定殖率随时间变化先降后升,在10月出现最高值;菌丝定殖率随时间变化先升后降,8月出现最高值;AM真菌孢子密度和定殖率的最大值分别出现在5月的0～10和20～30cm土层。实验站中土壤因子对AM真菌时空分布有显著影响,土壤速效N、速效P和有机质与孢子密度呈极显著正相关,土壤速效K与菌丝定殖率呈极显著正相关,和总定殖率成显著正相关。

英文摘要：

Aims Artemisia ordosica is a forage grass used for soil stabilization in arid regions, in- cluding our study area on the South Edge of Maowusu Sandy in Yulin, Shaanxi, China. Our objective was to determine the natural ecological distribution of AM fungi in relationship to soil factors in the rhizosphere ofA. ordosica in order to provide information for the recovery of desert vegetation. Methods We collected soil samples from the rhizosphere of Artemisia ordosica in four replicates, di- vided them into depths of 0-10, 10-20, 20-30, 30--40 and 40-50 cm, and measured colonization and ecological distribution of AM fungi. We analyzed AM fungi of A. ordosica rhizosphere soil using one-way ANVOA and correlated to soil factors. Important findings Spore density and arbuscular colonization of AM fungi decreased with sampling time. Vesicular colonization decreased initially and later increased to its highest value in October. Hy- phal colonization increased initially and later decreased; its highest value was in August. The highest colonization and spore density of AM fungi was at 0-10 cm and 20-30 cm depths in May. Soil factors were significantly correlated with the spatial and temporal distribution of AM fungi. Soil available N, available P and organic matter were significantly positively correlated with spore density, and soil available K was significantly correlated with hyphal colonization and total colonization.