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采用扫描和透射电镜技术系统地观察了禾谷镰刀菌 (Fusarium graminearum)在小麦穗部的侵染过程。接种后 6～12h ,分生孢子在小麦穗部的任何部位均可萌发 ,每个孢子可产生 1至多个芽管 ,新产生的芽管并不立即入侵寄主组织 ,而是在寄主体表生长扩展 ;接种后 36～ 4 8h观察 ,小穗颖片、外稃、内稃的内侧和子房的表面形成了密集的菌丝网 ,然而在小麦穗轴表面、颖片和内稃的外表面 ,菌丝生长缓慢、分布稀疏 ,但颖片外表边缘的菌丝可跨越边缘扩展到颖片的内表皮上 ;接种后 36h ,寄主体表菌丝产生入侵菌丝 ,以直接入侵方式由颖片、外稃、内稃的内侧及子房的顶部侵入寄主组织体内 ,随后 ,菌丝以胞间和胞内生长的方式向下扩展 ;接种后 4～ 5d ,菌丝由上述组织扩展到达穗轴后 ,在穗轴内沿微管束组织和皮层组织向上和向下扩展 ,延伸到相邻小花 ,随菌丝在小麦穗部组织内不断地生长扩展 ,使得寄主细胞坏死、解体 ,并最终导致整个麦穗的枯死
The infection process of Fusarium graminearum in wheat ears was systematically observed by scanning and transmission electron microscopy techniques. After inoculation 6 ~ 12h, conidia can sprout at any part of the wheat spike, each spore can produce 1 or more germ tube, the newly generated germ tube does not immediately invasion of the host tissue, but in the host body surface growth However, on the surface of wheat cob, the outer surface of the glume and the inner rachis, the outer surface of the glume and the inner rachis, Mycelium growth slow, sparsely distributed, but glume appearance of the edge of the mycelium can extend beyond the edge of the glume on the inner epidermis; 36h after inoculation mycoplasma invading mycelium invading hyphae by direct invasion by glume, The outer part of the nephew, the inner side of the nephew and the top of the ovary invade the host tissues. Subsequently, the hyphae extend downwardly in a manner of intercellular and intracellular growth. After 4 to 5 days after inoculation, the mycelium expands to reach the cob , Extend up and down along the tubules and cortical tissues within the cob, extend to the adjacent florets, continue to grow and expand with the mycelium in the wheat ear tissues, causing the host cells to necrosis, disintegration, and finally to the whole wheat Death of the ear