Anatomical Characteristics And Major Chemical Components&Microarea Distribution In Plectocomia Himalayana

Rattan is considered as plant resource with important economic value and development prospects,but the species with commercial value are decreasing.In order to increase the use and utilization rate of rattan and provides strong basic data for physical and mechanical research of rattan,Plectocomia himalayana is chosen as the object of study.The comprehensive analysis of the anatomical characteristics,cell wall layer properties,and chemical properties of the rattan were performed from the radial and axial directions.Electron microscopy was used to observe the ultrastructure of each cell,and microscopic confocal Raman technique was used to determine the distribution of cellular chemical components.The main conclusions are as follows:(1)The anatomical characteristics of Plectocomia himalayana are large different in radial.including: the fiber with small lumen and thick wall in cortex and with big lumen and thin wall in core;the tissue proportion of fiber,vessel and sieve fube in cortex were larger than in core;the vessel and vascular bundles was dense and small in cortex and large and sparse in core.The differences in internode and knot were the length-width ratio of fiber and parenchyma proportion smaller,the wall-lumen ratio of fiber and density of vessel larger in knot.(2)The MFA and crystallinity were 32.1° and 30.41% of Plectocomia himalayana,respectively,and the length-width ratio of the cellulose crystal was 1.98-3.64.The secondary wall(3 to 5 layers)of fiber cell was thicker and wes thinner in the secondary wall(3 to 7 layers)of the parenchyma cell.The secondary wall of vessel was tightly adherent and narrow.(3)The cellulose,acid-insoluble lignin,?-cellulose,phenyl alcohol extracts,and ash content were 66.91%,16.51%,42.55%,9.54%,1.41% of Plectocomia himalayana,respectively;The content of cellulose,lignin and ash was high in cortex while the content of hemicellulose and extracts in core was high.The highest concentration of cellulose was in the middle of the secondary wall of fiber,vessel and parenchyma cells,and the lowest was in the cytokeratin.On the contrary,the concentration of lignin was highest in the middle of the secondary wall,and the lowest concentration was in the cytokeratin.The difference of cellulose concentration between the inside and outside of secondary wall was small and the difference of lignin and hemicellulose concentration was relatively large.On fiber and vessel,the relative contents of cellulose and hemicellulose were highest and the relative content of lignin were lowest in cortex,the relative content of cellulose and hemicellulose were lowest and the relative content of lignin were highest in core.And the relative content of cellulose was smallest in core and the relative content of lignin was highest in cortex on parenchyma cell.