中文摘要：

【目的】了解内蒙古阿拉善和宁夏天然草原的小花棘豆和变异黄芪不同组织中内生真菌Undifilum oxytropis的显微分布特点和含量分布规律。【方法】通过石蜡切片结合乳酸酚棉蓝染色法观察，采用实时荧光定量PCR（RT—qPCR）进行定量研究，获得各组织（茎、叶、种子和根）中内生真菌分布和含量。【结果】种子中内生真菌主要定殖于种皮栅栏组织与薄壁组织两层的细胞间隙；叶片组织主要定殖于靠近气孔的表皮细胞层，茎髓中内生真菌围绕于茎髓质维管柬纵轴边缘的薄壁细胞层中；RT—qPCR的检测限为0．029pg／ng总DNA，各采样点相应组织内生真菌含量不同，两采样点小花棘豆种子中U．oxytropis含量均为最高，叶和茎相反，两地变异黄芪为种子中最高，根最低，叶和茎相反。【结论】内生真菌寄生在植物组织时对宿主组织和细胞类型均有选择性，生境对疯草中内生真菌的定殖和分布也有影响。

英文摘要：

[ Objective] The characteristics of microscopic distribution and content of Undifilum oxytropis were observed and quantified in different tissues of Oxytropis glabra and Astragalus variabilis from natural grasslands of Inner Mongolia and Ningxia Province. [ Methods] Distribution of fungal endophyte was obtained in all the tissues （stems, leaves, seeds and roots） of O. glabra and A. variabilis though paraffin section and staining method of lactic acid phenol cotton blue; and content of fungal endophyte was determined though Real time-qPCR. [ Results] Endophytc fungi were observed mainly within the gap between the palisade tissue and parenchymatous tissue of seed coat in seed, mainly colonized in the superficial cells layer near stoma in the leaves, and in pith of stem mainly plants in the parenchymatous tissue around the edge of the vertical axis of the vascular bundle. There was an obviously difference in concentration of U. oxytropis in the plants collected in different locations. The content of U. oxytropis was highest in all seeds of O. glabra, while it was opposite in stems and leaves of two sampling points. Similarly, the content of U. oxytropis was highest in seeds, it was lowest in roots, and stems and leaves were opposite in A. variabilis from two sampling points. The detection limit was 0. 029 pg/ng total DNA by Real time-qPCR. [ Conclusion] When endophytic fungi infected the tissues of plants, there was selectivity to the tissues and cell type of host, and the colonization and distribution were influenced by habitats in fungal endophytes of locoweeds.