红麻及其同属近缘植物韧皮纤维与木质纤维形态结构研究

A Study on the Morphology and Microstructure of the Phloem Fibers and the Xylems in Kenaf and Its Homologues

采用光学与电子显微技术，对红麻近缘植物的韧皮纤维与木质纤维的形态结构进行了比较研究。结果表明，红麻近缘植物韧皮纤维均呈束状结构，以次生纤维较多，单纤维长度为１．００～２．７３ｍｍ，纤维表面有多条明显的纵向突起或沟槽，有多个外交型、内陷型和平滑型结节，并伴有程度不等的裂隙、转折或扭曲，节间长度为１５４．０８～４４９．０１μｍ，胞壁上的孔洞较少较小，纤维表面巨原纤呈圆柱形，趋向纤维轴向排列。木质纤维亦以次生纤维较多，主要呈射线状排列，单纤维长度为０．７０～１．０７ｍｍ，结节、转折和扭曲极少，胞壁上孔洞较多较大，孔径为０．０５～３．５μｍ，纤维表面巨原纤分布较稀少，与纤维轴向的夹角较大。

Light microscopic and SEM studies on the morphology and microstructure of the phloem fibers and the xylems in kenaf and its homologues have been carried out. Results show that most of the phloem fibers present themselves in fiber bundles with secondary growths predominating. Individual fiber length is found to be in the range of 1. 00 2. 73 mm. Longitudinal protrusions and/or grooves are conspicuously observable along the surfaces of the fibers. A number of nodes protruding and/or lying flat on the surfaces of the fibers are also being observed. Nodes are usually cleavaged, winding and/or twisting to different extents. The distance between nodes ranges from 154. 08μm to 449. o1μm. Very few cavities are found on the cell walls, and if found they are usually small in aperture if present. Maicrofibrils, usually cylindrical in shape,are observed on the surfaces of the cell wall, oriented towards the fiber axis and exhibiting mterwoven networks. For xylems in kenaf and its homologues, secondary grown fibers are also found to be predominating. Xylem fibers, however, are shorter in length, ranging 0. 70 l. 07μm. and are mostly radially oriented. The nodes in xylems seem to be free from windings and twistings. Larger cavities, ranging 0. 05 3. 5μm are found on the surfaces of xylem cell walls. Microfibrils are obviously less popualated in xylem cell wall surfaces, and when present, they are oriented at a rather significant angle with the fiber axis.