木竹材の異方的収縮に関する研究

Abstract

1) The principal cause of anisotropic shrinkage in the transverse section of wood are based upon the cell-wall structure. And the following factors in cell-wall structure for the anisotropic shrinkage are indicated : a. the microschemical structure of compound middle lamella in cell-wall b. the microschemical structure of amorphous region in secondary wall c. the fibril angles in central layer of secondary wall 2) The factors a and b in 1) are closely connected with the contained lignin in cell-wall. And the effect of factors a and b upon the anisotropic shrinkage of wood is larger than the one of factor c. 3) The relation between factor a. and anisotropic shrinkage in transverse section seems to be due to the restraint action of compound middle lamella for the shrinkage of secondary wall in cell-wall. And the relations between factors b or c and anisotropic shrinkage seems to be due to the connections of these factors with the distribution of active hydroxyl groups. 4) The secondary cause of anisotropic shrinkage in the transverse section of wood are based upon the microscopical structure of wood, above all the volumetric proportions of tangential and radial wall of tracheid in the transverse section of spring- and summerwood, the shapes of tracheid cell in the transverse section of spring- and summerwood, the bordered pit in tracheid radial wall of springwood and the volumetric proportion of wood ray in wood. 5) The cause of anisotropic shrinkage in transverse section of bamboo are based upon the microscopic structure, above all the proportion of bundle sheath and the ratio of maximum width in radial direction to the one in tangential direction of a vascular bundle.