毛乌素沙地油蒿根际AM真菌空间分布研究

油蒿(Artemisia ordosica)是鄂尔多斯高原南部毛乌素沙地的重要固沙植物和荒漠草原优势植物,系统研究油蒿根际AM真菌生态分布,对于充分利用AM真菌资源,促进油蒿生长、生态环境重建和植被恢复具有重要意义。在毛乌素沙地自北向南选取2个代表性样地,从油蒿根际0-10、10-20、20-30、30-40和40-50 cm5个土层分别采集土壤样品,研究了油蒿根际丛枝菌根真菌的种类和分布。结果表明:丛枝菌根真菌的种类和分布具有明显的空间特征,并与样地土壤因子密切相关。在分离的3属8种丛枝菌根真菌中,黑球囊霉(Glomusmelanosporum)仅出现在研究站的油蒿根际,而聚丛球囊霉(Glomus aggregatum)和瑞氏无梗囊霉(Acaulosporarehmii)仅出现在榆林的油蒿根际。丛枝菌根类型为I-型(Intermediate type),泡囊形态多样,最高定殖率和最大孢子密度均出现在0-10 cm土层,并随土层加深呈下降趋势。孢子密度与碱解氮和有机质呈极显著正相关。说明在极端干旱条件下,油蒿能与丛枝菌根真菌形成良好的共生关系,而孢子密度和丛枝菌根不同结构有助于土壤环境的微观监测和评价。

Studies on spacial distribution of arbuscular mycorrhizal fungi in the rhizospheres of Artemisia ordosica in Mu Us sandland

Artemisia ordosica is a kind of important sand-fixing plants and desert-steppe predominant plants in Mu Us of south of Ordos plateau.Studies on ecological distribution of arbuscular mycorrhizal fungi in the rhizospheres of Artemisia ordosica is important to accelerate growth of Artemisia ordosica,rebuild ecological environment and resume vegetation by using enough arbuscular mycorrhizal fungi resource.This paper researched species and distribution of arbuscular mycorrhizal fungi in the rhizospheres of Artemisia ordosica.Soil samples were collected in 4 replicates and divided a depth of 50 cm into 5 sections,i.e.0-10,10-20,20-30,30-40 and 40-50 cm in the rhizosphere of each plant in two representative sites from north to south in Mu Us sandland.The results showed that species and distribution of arbuscular mycorrhizal fungi took on obvious spacial character and correlated with soil factors.Glomus melanosporum was in Yanjiuzhan,Glomus aggregatum and Acaulospora rehmii were in Yulin.Mycorrhizal type was intermediate type and morphology various vesicles,colonization rate and spore density of 0-10 cm depth were maximal and they descended with soil deepth.Soil alkali solution N and organic matter had significantly positive effect on spore density.Artemisia ordosica could form symbiosis with arbuscular mycorrhizal fungi under extreme drought condition.Spore density and arbuscular mycorrhizal structures are useful indictors for microcosmic monitoring and evaluating soil environment.