Fig. 5.

Light micrographs showing transverse views of the cambial zone and differentiating xylem after 72 d on 13 April 2012. In the control seedlings (A), enlarging vessel elements were observed (asterisk; A). Some vessel elements were located in the first layer from the previous year's xylem (arrowhead; A). In the disbudded seedling (B), many new thin cell plates were visible (arrows and arrowhead; B), demonstrating that cambial cell division occurred in the absence of buds. In some radial files, cell divisions in the first layer of fusiform cells from the previous year's xylem were observed (arrowhead; B). Scale bars = 50 μm.