Objective  In order to enrich the basic anatomical data and promote the high value-added utilization of culm resources of Chimonobambusa utilis, the composition and morphology of cell and structural characteristics of the cell wall were investigated, and the variation regularity with age and axial part of bamboo culm as well as the correlation with environmental and climatic factors were also revealed.

  Method  In this study, the natural plants of Chimonobambusa utilis were used as raw material to prepare the permanent transverse and longitudinal slices and isolated single fibers by the traditional slicing process and Franklin dissociation method. The tissue percentage, vascular bundles, fiber cells, parenchyma cells of basic tissues, and cell wall layer structure were characterized by stereo and bio-optical microscopy as well as field-emission scanning electron microscopy (FE-SEM).

  Result  The proportion of basic tissues was the largest in Chimonobambusa utilis, ranging from 56.16% to 65.92%, followed by the fibrous tissues with the proportion from 27.69% to 34.18%, while the conduction tissues showed the smallest proportion ranging from 6.40% to 9.85%. The types of vascular bundle belong to open and semi-open. The density and radial width as well as tangential width of vascular bundles varied significantly with age and axial part of bamboo culm. The radial-tangential ratios were almost the same, ranging from 1.2 to 1.3. The length of fiber cells ranged from 1.7 to 2.1 mm, and the length-width ratios were 110−133, which can be classified into long fiber. Various morphologies and their considerable variation in the radial direction existed in the parenchyma cells. The number of secondary wall layers of fiber cells was odd, with a maximum of 9 layers, showing the characteristics of alternating width and narrowness. The number of secondary wall layers of parenchyma long cells was also odd, with a maximum of 9 layers. The thickness of each layer was approximately equal, showing the alternative characteristics of loosening and tightening. There was variation in the number of cell wall layers at different locations in the bamboo wall, but the difference in the highest number of cell wall layers with age and axial part of the bamboo culm was not significant. The proportion of conduction tissues was significantly affected by average annual precipitation, which showed negatively correlation. Whereas the vascular bundle size and secondary wall thickening of parenchyma long cells were significantly affected by temperatures, which were negatively correlated with the former and positively correlated with the latter.

  Conclusion  The microstructure of Chimonobambusa utilis is different without obvious regularity as the changes in bamboo ages and axial part of bamboo culm, which are relatively stable for 3−4 years old bamboo. In addition, there are some correlations between environmental and climatic factors and the structural characteristics of Chimonobambusa utilis, and there are significant correlations with the proportion of conduction tissues, vascular bundle size, and secondary wall thickening of parenchyma cells.