Development Changes of Cambial Initials and Their Derivative Cells in the Trunk of Diospyros kaki THUNB. and Firmiana simplex W.F. WIGHT in Relation to Girth Increase

감나무와 벽오동 수간의 둘레증가에 따른 형성층 원시세포와 그 유도세포의 발생학적 변화

This study has been conducted to investigate the developmental changes of cambial initials and their derivatives in relation to the growing girth of tree in Diosypros kaki and Firmiana simplex. In D. Kaki and F. simplex with typical storeyed cambium, increase in the girth of camium occurred by radial anticlinal division in general, however occasionally the increase was companied by pseudotransverse division. The length of fusiform initials, vessel member, and sieve tube member remained relatively constant throughout the secondary growth but that of fiber showed general tendancy to increase with growing girth of tree. During the girth increase of tree, height and number of ray remained constant in D. kaki, however in F. simplex, height of ray markedly decreased while the number of ray per unit area more or less increased. The secondary ray was originated from the segmentation or division of the side or end of fusiform initials.