ORIENTATION OF MICROFIBRILS AND MICROTUBULES IN DEVELOPING TENSION-WOOD FIBERS OF JAPANESE ASH (FRAXINUS-MANDSHURICA VAR JAPONICA)
ORIENTATION OF MICROFIBRILS AND MICROTUBULES IN DEVELOPING TENSION-WOOD FIBERS OF JAPANESE ASH (FRAXINUS-MANDSHURICA VAR JAPONICA)
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DOI：
10.1007/bf00203659
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发表时间：
1995-06-01
期刊：
影响因子：
4.3
通讯作者：
FUKAZAWA, K
中科院分区：
文献类型：
--
作者：
PRODHAN, AKMA;FUNADA, R;FUKAZAWA, K
研究了水曲柳(Fraxinus mandshurica Rupr.)纤维发育过程中纤维素微纤维(MFS)的取向和皮质微管(MTS)的排列。瓦尔[中英文摘要]用电子显微镜和免疫荧光显微镜对树木进行了观察。在次生壁开始增厚时，MFS与纤维的纵轴成约45度角，呈S螺旋取向。MFS逐渐改变方向，从S螺旋开始顺时针旋转(从管腔一侧看)，直到它们与纤维轴大致平行。这种构型可以被认为是半螺旋形图案。随着旋转的停止，由于平行的具有一致织构的MFS的反复沉积，形成了厚厚的凝胶层(G-)。在G层沉积的后期，根据MFS的取向，可识别出两种类型的凝胶纤维。类型1的微原纤维平行于纤维轴；类型2的微纤维以逆时针方向铺设。MFS的逆时针旋转与MFS相对于纤维轴的角度变化有关，变化范围从5度到25度，纤维之间呈Z-螺旋方向。在G层形成的所有沉积阶段，MFS都表现出高度的平行度。在G层中未观察到S螺旋取向的金属纤维。在此基础上，提出了S-1+G型次生壁组织的MFS在次生壁的取向和沉积模型。在G层形成期间，MT阵列逐渐改变，顺时针旋转(从管腔一侧观察)，从Z螺旋方向上大约35-40度的角度到大约0度(平行)纤维轴线的角度。MTS和MFS之间存在明显的平行关系。在G层形成过程中，发育中的张力木纤维中MTS的密度约为每亩壁17-18个。可见，高密度的MTS对木材纤维次生壁中新生的MFS的取向起着重要的调节作用。MFS之间的高度并行度似乎与以高密度存在的MT的并行性密切相关。
The orientation of cellulose microfibrils (MFs) and the arrangement of cortical microtubules (MTs) in the developing tension-wood fibres of Japanese ash (Fraxinus mandshurica Rupr. var. japonica Maxim.) trees were investigated by electron and immunofluorescence microscopy. The MFs were deposited at an angle of about 45 degrees to the longitudinal axis of the fibre in an S-helical orientation at the initiation of secondary wall thickening. The MFs changed their orientation progressively, with clockwise rotation (viewed from the lumen side), from the S-helix until they were oriented approximately parallel to the fibre axis. This configuration can be considered as a semi-helicoidal pattern. With arresting of rotation, a thick gelatinous (G-) layer was developed as a result of the repeated deposition of parallel MFs with a consistent texture. Two types of gelatinous fibre were identified on the basis of the orientation of MFs at the later stage of G-layer deposition. Microfibrils of type 1 were oriented parallel to the fibre axis; MFs of type 2 were laid down with counterclockwise rotation. The counterclockwise rotation of MFs was associated with a variation in the angle of MFs with respect to the fibre axis that ranged from 5 degrees to 25 degrees with a Z-helical orientation among the fibres. The MFs showed a high degree of parallelism at all stages of deposition during G-layer formation. No MFs with an S-helical orientation were observed in the G-layer. Based on these results, a model for the orientation and deposition of MFs in the secondary wall of tension-wood fibres with an S-1 + G type of wall organization is proposed. The MT arrays changed progressively, with clockwise rotation (viewed from the lumen side), from an angle of about 35-40 degrees in a Z-helical orientation to an angle of approximately 0 degrees (parallel) to the fibre axis during G-layer formation. The parallelism between MTs and MFs was evident. The density of MTs in the developing tension-wood fibres during formation of the G-layer was about 17-18 per mu m of wall. It appears that MTs with a high density play a significant role in regulating the orientation of nascent MFs in the secondary walls of wood fibres. It also appears that the high degree of parallelism among MFs is closely related to the parallelism of MTs that are present at a high density.