Abstract: [Objective] To observe the pit morphology and distribution in moso bamboo, resin casting, a very proper way to obtain three-dimensional duplicate of pits, was applied.[Method] A two-component resin BS was used to complete the following procedures, infiltration of resin, resin curing, corrosion of bamboo tissue and dry cleaning in order. Resin casts of different types of individual cell and cells within certain scope served to reveal characteristics of pits in cell wall, pit pairs between cells and channels in vascular bundle. Moreover, a combination with observing bamboo sections was able to make verification of result getting from two ways.[Result] Pits in metaxylem vessels of moso bamboo presented a high selectivity of distribution, that is, large scale of pits were centered in single side of cell wall near to the geometric center of vascular bundle, though pits in the other side turned to be the opposite. And clear pit border structure was found. Diameter of pit aperture and pit membrane of vessel resin casts were 0.9-2.7 μm and 1.1-3.8 μm respectively. There were some smaller metaxylem vessel elements scattered or arranged adjacent connecting with bordered pit. As for parenchyma cells within the vascular bundle, pits were more and larger than those in the ground tissue. And parenchyma cells adjacent to metaxylem showed particularity. Pits in fiber cells were in sparse distribution with small openings, long and narrow cavities and suspect pit borders. Cells in vascular bundle connected each other through the pit and formatted space networks further.[Conclusion] Resin casting, which is capable of showing the pit stereo structure and reflecting diffusion permeation of specific fluid inside bamboo both directly and objectively, is a suitable method for investigating pits in moso bamboo.

Key words: bamboo, cell wall, pit, resin casting