大麦根中禾谷多粘菌休眠孢子堆的超微结构

ULTRASTRUCTURE OF CYSTOSORI OF POLYMYXA GRAMINIS IN BARLEY ROOTS

通过扫描电镜和透射电镜观察了禾谷多粘菌PolymyxagraminisLed．休眠孢子堆的超微结构。休眠孢子堆仅分布于寄主根表皮细胞中。休眠孢子堆形状不一，有的呈球状，有的呈律状，少则由几十个，多则由数百个紧密排列的休眠孢子组成。休眠孢子彼此通过刺突连接，细胞壁分4层，第三层局部区域结构松散，可能与初生游动孢子萌发孔有关。成熟休眠孢子细胞质丰富，细胞质膜内侧含有大量脂质粒，细胞质中央含一个细胞核，围围分布线粒体、内质网、高尔基体、液泡等细胞器。成熟的休眠孢子在越夏前大多数已释放初生游动孢子，只剩下空壳。表面凹陷是已释放游动孢子的休眠孢子一个特征。本文还讨论了禾谷多粘菌休眠孢子在病害流行学中的作用。

Ultrastructures of cystosori of Polymyxa graminis were observed by scanning and transmission electron microscopy. The cystosori only distributed in the epidermal cells of barley roots. The shapes of cystosori were indefinite, either spherical or rod-shape, and associated with the shapes of the host cells where they were. A cystosori was clustered with hundreds of resting spores which connected through spines extended from the outer layer of the walls. The wall of resting spores consisted of 4 layers, and the third layer showed unstained plug, extending up to half of the circumference of the spore, and always facing towards outside, which might be associated with germination although it was not clear how it opened to release the primary zoospore. Mature resting spores contained rich cytoplasm where contained a nucleus in the center and numerous lipophic bodies, mitochondria, endoplasmic reticulum, golgi apparatus, and expulsion vacuoles. Most matured resting spores released primary zoospores before over summer and remained the empty shells, which showed a feature of sunken surface. The role of cystosori of P. graminis in the epidemiology of virus disease which it transmitted was also discussed.