Molecular Construction on the Formation of Cell Wall by Immunofluorescence Microscopy

我们用冰冻切片用免疫荧光显微镜观察了七叶树伸长上胚轴中皮质MT的排列。在黑暗和明暗两种生长条件下，MT的排列与伸长速率有关，且在同一上胚轴上因区域不同而不同。结果表明，在伸长停止前，皮质MTs的排列发生了从横向到斜向或纵向的变化。在这两种生长条件下，细胞外MTS的取向似乎比内薄壁细胞陡峭，并且在明暗生长的上胚轴中变化较早。杨树悬浮培养细胞在连续提取细胞壁多糖前后，经过快速冷冻和深度蚀刻技术，观察了细胞壁结构的变化，并用果胶降解酶处理后对细胞壁结构进行了观察。我们的观察表明，用化学和酶处理提取果胶后，纤维间隙或孔大小增加。经4%KOH处理后，纤维微纤丝的有序间距变化不大，24%KOH处理后，纤维微纤丝的有序间距发生了显著变化。这些结果表明，半纤维素，可能是木葡聚糖，可能通过在双子叶植物细胞壁中的纤维间多糖连接来维持三维构象。

We examined the arrangement of cortical MTs in the elongating epicotyl of Aesculus turbinata by immunofluorescence microscopy using cryosections. Under both dark and light-dark growth conditions, the arrangement of MTs was associated with the rates of elongation and differed according to the region in the same epicotyl. The present results indicate that the change in the arrangement of cortical MTs from transverse to oblique or longitudinal ones occurs in the cortex before elongation stops. Orientation of MTs in both growth conditions seems to be steeper in the outer than in the inner parenchyma cells and to change earlier in the light-dark grown epicotyl.The architecture of the primary wall in poplar suspension-cultured cells was observed after rapid freezing and deep etching techniques before and after the sequential extraction of cell wall polysaccharides.The cell wall architecture was also examined after the treatment by pectin-degrading enzymes. Our observations showed that the inter-fibrillar spaces or pore size increases after extraction of pectins both with chemical and enzymatic treatments. The ordered spacing of cellulose microfibrils was only slightly altered after 4 % KOH-treatment and drastically altered after 24 % KOH-treatment. These results suggest that the hemicellulose, possibly xyloglucan, may have apossible role in maintaining the three-dimensional conformation by inter-fibrillar polysaccharide linkages in the cell wall of this dicotyledonous species.