毛竹茎秆纤维发育过程的超微结构观察

利用透射和扫描电镜观察了毛竹(Phyllostachys edulis(Carr.)H.De Lehaie)茎秆纤维发育过程中的超微结构变化.在纤维细胞初生壁形成期,细胞质中线粒体、内质网、高尔基体等细胞器数量有明显的增加,出现大量的由内质网与高尔基体分泌形成的运输小泡,周质微管平行分布于质膜内侧,出现环状片层结构,并在细胞壁与质膜之间出现壁旁体结构.随着次生壁的逐渐形成,细胞质中细胞器逐渐地解体并出现多泡小体;纤维细胞核出现染色质凝聚并边缘化,但在8年生的纤维中可以持续存在;在纤维次生壁形成的整个阶段都存在与周围细胞相联系的胞间连丝和运输小泡;次生壁在前4年加厚明显,以后加厚程度减缓,但可以持续很长一段时间,并随着加厚出现宽窄交替的多层结构.结果表明,线粒体、内质网、高尔基体和壁旁体等细胞器与周质微管一起参与了初生壁和次生壁早期的形成;纤维细胞次生壁的形成过程就是一个漫长的程序性细胞死亡(PCD),而PCD的产物与胞间连丝一起参与了次生壁的形成与加厚;染色质凝聚并边缘化的细胞核与胞间连丝的持续存在,证明毛竹茎秆纤维细胞是一种典型的长寿细胞.

Ultrastructural Study of the Fiber Developmental Process in the Culms of Phyllostachys edulis

Ultrastructural changes in the fiber of Phyllostachys edulis (Carr.) H. De Lehaie culmsduring the developmental process were investigated with transmission and scanning electronmicroscopy. The results suggested that mitochondrion, rough endoplasmic reticulum, Golgi bodies,lomasomes and cortical microtubules were correlative to the formation of primary wall and secondarywall of earlier stage. In the earlier stage of secondary wall formation, chromatin agglutination, swellingand disintegration of organelles, and multivesicular bodies, etc. appeared in fiber cytoplasm. Fibernucleus with the chromatin agglutination would keep for a long time, which implied that secondary wallformation stage of fiber in Phyllostachys edulis culms was a programmed cell death. Along with thefurther development of fiber, secondary wall continued thickening: the thickening level obviouslyincreased in the former 4 years, and then gradually decreased. During the secondary wall formation,polylaminate structures of wall appeared in the fiber, with the persistence of plasmodesmata andtransfer vesicles between fiber and its surrounding cells. The persistence of nucleus and plasmodes-mata indicated the characteristic of long-lived cell of fiber.