珠状巨孢囊霉孢子的扫描和透射电镜观察

Observation of Gigaspora margarita Spore-Wall with Scan and Transmission Electricity Microscope

对珠状巨孢囊霉Gigaspora margarita孢子壁进行了扫描电镜（SEM）和透射电镜（TEM）观察．SEM观察到孢子外壁有不规则的侵蚀状小孔，且表面附着有多种形态的微生物．TEM观察到整个孢子壁由4层组成．最外层孢壁（I层）厚1．5—1．8μm；次外层孢壁（Ⅱ层）为条纹状的刚性层，厚0．6～0．8μm；第Ⅲ层孢壁约占整个孢子壁的80％，该层孢壁存在隐约的亚层结构，部分第Ⅲ层孢壁出现侵蚀层，侵蚀层中分布着大量由微小颗粒状生物体聚集成的细胞团；最内层孢壁（Ⅳ层）非常薄，仅0．15～0．20μm，其内侧间隔分布有因内壁加厚形成的乳凸状结构．观察到的与珠状巨孢囊霉孢子壁紧密联系的微生物可能具有特殊的生态功能，值得深入研究．

Spore-wall of arbuscular mycorrhizal fungus Gigaspora margarita was observed with scan electricity microscope （SEM） and transmission electricity microscope （TEM）. SEM observation demonstrated many irregular eroded pits and diversity of microorganisms on the surface of the spore. TEM observation indicated that the spore-wall was composed of four layers. The outer layer was 1.5 - 1.8 μm thick, the second layer was 0. 6 - 0. 8μm thick with stripe and rigidity, and the third layer was relatively thicker and accounting for up to 80% of the whole spore-wall. In the third layer, some indistinct sublayers were observed, clear eroded sublayers also appeared in partial sections, and lots of small granule-shaped organisms unevenly clustered in these eroded sublayers. The innermost layer was very thin, about O. 15 -0. 20 μm, and some warts due to the thickening of the inner wall discontinuously distributed in inside of this layer. Those microorganisms tightly associated with G. margarita spore may possess potential special ecological functions, and further study on it is deserved.