金佛山方竹细胞构成、形态及细胞壁层构造变异性

Variability of cell composition,morphology and cell wall structure in Chimonobambusa utilis

【目的】为探究金佛山方竹细胞构成、形态及其细胞壁层构造特征,揭示其随竹龄、竹秆轴向部位的变化规律以及与环境气候因素的相关性,从而丰富其基础解剖数据,促进金佛山方竹秆材资源的高值化利用。【方法】以1~5年生金佛山方竹天然植株为研究对象,采用传统切片法和富兰克林离析法制得永久横纵切片和离析单根纤维,通过光学显微镜和场发射扫描电镜观察并测量其组织比量、维管束、纤维细胞、基本组织薄壁细胞以及细胞壁壁层结构等特征。【结果】金佛山方竹基本组织占比(体积比)最大,为56.16%~65.92%;纤维组织占比次之,为27.69%~34.18%;输导组织占比最小,为6.40%~9.85%。维管束类型为开放型和半开放型,维管束密度、径向宽度和弦向宽度随竹龄、竹秆轴向变化差异均显著,宽度径弦比几乎一致,介于1.2~1.3之间。纤维细胞长度在1.7~2.1 mm之间,长宽比为110~133,属于长纤维等级。薄壁细胞形态多样,存在显著的竹壁径向差异。纤维细胞次生壁层数为奇数层,最高达9层,呈现出宽窄交替的特征;薄壁细胞次生壁层数也为奇数层,最高达9层,每层厚度近似相等,呈现出松紧相间的特征。竹壁不同位置的细胞壁层数存在差异性,但细胞壁最高层数随竹龄与竹秆轴向部位变化差异不显著。年平均降水量显著影响金佛山方竹的输导组织比量,呈负相关关系;气温显著影响维管束尺寸和薄壁细胞次生壁厚,前者呈负相关关系,后者呈正相关关系。【结论】金佛山方竹显微构造特征在竹龄和竹秆轴向部位两个变化模式下存在一定的构造差异性,但没有明显变化规律,3~4年生金佛山方竹显微构造特征相对趋于稳定。此外,环境气候因素与金佛山方竹解剖构造特征均存在一定的相关性,且与输导组织比量、维管束尺寸和薄壁细胞次生壁厚等存在显著相关性。

[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.