Keywords: 
• woody science /
• bamboo properties /
• fiber /
• vessel element /
• variation

Abstract: To determine variation in fiber and vessel elements with respect to positions along the longitudinal direction （bottom，middle，and top of the culm） and the radial direction （from the inner part to the outer part of the culm wall） of Guadua amplexifolia，the length and width of fiber and vessel elements were measured. Results showed that fiber and vessel elements were varying in length from 1 738 to 2 764 m and from 383 to 526 m，in width from 13 to 20 m and from 99 to 288 m，and in ratios of length to width from 91 to 211 and from 1.3 to 4.4. For the culm，fiber length and ratio of length to width were in the order：bottom ＜ middle ＜ top，but fiber width was reversed （bottom ＞ middle ＞ top）. In the radial direction，fiber length and ratio of length to width increased first and then decreased gradually. Fiber width in the bottom and middle of the culm did not vary，whereas in the top of the culm it was higher for the inner and outer parts. In the longitudinal direction，there was no variation in vessel element length；for vessel element width，the bottom，compared to the middle and top，was higher even if there was no variation between the middle and top，but for the length to width ratio，the reverse was true. In the radial direction，there was no variation for vessel element length，the width of the vessel elements decreased，and there was no variation for the length to width ratio of vessel elements from the inner to the middle part；however，there was an increase from the middle to the outer part of the culm wall.［Ch，6 fig. 2 tab. 14 ref.］