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Three-dimentional images of deposition of microfibrils and matrix substances in the cell wall

细胞壁中微纤维和基质物质沉积的三维图像

基本信息

批准号：
06404013
负责人：
SANO Yoshihiro
金额：
$ 15.81万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

The arrangement of cortical microtubules (MTs) in differentiating tracheids of conifers was examined by confocal laser scanning microscopy after immunofluorescent staining. The arrays of MTs in the tracheids during formation of the primary wall were not well ordered and the predominant orientation changed from longitudinal to transverse. During formation of the secondary wall, the arrays of MTs were well ordered and their orientation changed progressively from a flat S-helix to a steep Z-helix and then to a flat S-helix as the differentiation of tracheids proceeded. The orientation of cellulose microfibrils (MFs) on the innermost surface of cell walls observed by FE-SEM changed in a similar manner to that of the MTs. The MFs changed their orientation, with clockwise rotation (viewed from the lumen side), from a flat S-helix to a steep Z-helix and then from a steep Z-helix to a flat S-helix during the formation of secondary wall. These results provide strong evidence for the co-alignment of MTs and MFs during the formation of the semi-helicoidal texture of the cell wall in conifer tracheids. No tracheids in which the MTs had been disassembled were observed in any radial series during the successive steps of differentiation. The orientation of MTs might change progressively without depolymerization of MTs, supporting the dynamic helical model. On the basis of our results, we propose a model for the orientation of MTs and MFs during the differentiation of tracheids.

免疫荧光染色后，用激光共聚焦扫描显微镜观察了针叶树分化管胞中皮质微管的排列。在初生壁的形成过程中，管胞中的MTS排列不整齐，优势取向由纵向变为横向。在次生壁的形成过程中，线粒体排列有序，随着管胞分化的进行，排列方向由扁平的S螺旋逐渐向陡峭的Z螺旋转变，再向扁平的S螺旋转变。FE-SEM观察到细胞壁最内表面的纤维微原纤维(MFS)取向发生了与MTS相似的变化。在次生壁的形成过程中，MFS的取向发生了改变，从管腔侧面看是顺时针旋转的，从平坦的S螺旋到陡峭的Z螺旋，再从陡峭的Z螺旋到平坦的S螺旋。这些结果为针叶树管胞细胞壁半螺旋结构形成过程中MTS和MFS的共同排列提供了强有力的证据。在连续的分化过程中，没有观察到任何径向系列的管胞中的MTS已经被分解。在没有解聚的情况下，MTS的取向可能会逐渐改变，支持动态螺旋模型。在此基础上，我们提出了管胞分化过程中MTS和MFS定向的模型。