荒漠生境油蒿根围AM真菌多样性

为了阐明荒漠生境主要植被油蒿(Artemisia ordosica)根围AM真菌多样性, 2007年8月从毛乌素沙地和腾格里沙漠选取榆林、盐池、研究站和沙坡头4个样地, 按0–10、10–20、20–30、30–40、40–50 cm 5个土层采集油蒿根围土壤样品, 研究了油蒿根围AM真菌物种多样性和生态分布。在分离的4属28种AM真菌中, 球囊霉属(Glomus)16种, 无梗囊霉属(Acaulospora)7种, 盾巨孢囊霉属(Scutellospora)4种, 多孢囊霉属(Diversispora)1种。4个样地的共同优势种为摩西球囊霉(G. mosseae), 共同常见种为双网无梗囊霉(A. bireticulata)和网状球囊霉(G. reticulatum), 共同稀有种为缩球囊霉(G. constrictum)。地球囊霉(G. geosporum)仅出现在盐池, 蜜色无梗囊霉(A. mellea)、帚状球囊霉(G. coremioides)、浅窝无梗囊霉(A. lacunosa)和宽柄球囊霉(G. magnicaule)仅出现在研究站, 黑球囊霉(G. melanosporum)仅出现在榆林。盐池与研究站样地AM真菌种类最多, 榆林样地孢子密度最大, 沙坡头样地种类和孢子密度显著偏低。总体上, 孢子密度、分离频度、相对多度和重要值依Glomus >Acaulospora > Scutellospora> Diversispora呈现显著减小趋势。结果表明, 油蒿与AM真菌之间有良好共生性, 这对进一步利用菌根生物技术维护荒漠生态系统结构的完整性具有重要意义。

Diversity of arbuscular mycorrhizal fungi associated with a desert plant Artemisia ordosica

To elucidate the diversity of arbuscular mycorrhizal (AM) fungi associated with the common desert plant Artemisia ordosica, we sampled, in April 2007, the following four representative sites in the Mu Us Sandland and Tengger Desert regions: Yulin Psammophyte Garden (Yulin), Yanchi Desert Shrub Garden (Yanchi), Ordos Sandland Ecological Research Station (Research Station), and Shapotou Desert Research and Experiment Station (Shapotou). We collected soil samples from the rhizosphere of A. ordosica and divided them into five depth intervals, each 10 cm, to 50 cm depth. A total of 28 AM fungal species from four genera were isolated. Of these, 16 species belonged to Glomus, 7 to Acaulospora, 4 to Scutellospora and 1 to Diversispora. Glomus mosseae was the dominant species. Acaulospora bireticulata and G. reticulatum were common species (>25% frequency of occurence) and G. constrictum was rare species (<25% frequency of occurence) at the four sampling sites. Glomus geosporum was found only in Yanchi, G. melanosporum only in Yulin and A. mellea, A. lacunosa, G. coremioides and G. magnicaule occurred only in Research Station. Richness of AM species was highest in Yanchi and Research Station and spore density was highest in Yulin. Species richness and spore density were the lowest in Shapotou. Generally, spore density, isolation frequency, relative abundance and importance value followed the trend Glomus >Acaulospora > Paraglomus > Diversispora. Our results are the first to assess the considerable diversity of arbuscular mycorrhizal fungi found in association with Artemisia ordosica. Further research should concentrate on understanding the dynamics of these relationships.