刺桐(Erythrina arborescens Roxb.)维管分生组织原形成层的发育

THE DEVELOPMENT OF PROCAMBIUM OF THE VASCULAR CAMBIUM IN ERYTHRINA ARBORESCENS ROXB

刺桐的一年生枝条 ,在距顶端约 180 μm处 ,由顶端分生组织分化出剩余分生组织 ;在距顶端约2 40 μm处 ,剩余分生组织分散形成原形成层束 .原形成层细胞向外、向内分别衍化出原生木质部和原生韧皮部 .由于原形成层细胞横分裂频率的不同 ,产生长、短两类细胞 ,短细胞与束间细胞一样 ,含有淀粉粒 .原形成层束间的基本分生组织可以分裂产生新的维管束 .

Erythrina arborescens Roxb . is a species of arbor in Leguminosae, which grows very fast. At the point of 180μm from the top of the branch. its apical meristems develop into residual meristems; At the point of 240 μm from the top of the brancl, residual meristems develop into procambium strands. The procambiumi produces protoxylem in the out side and protophloem in the inner side. Because of the difference of the cells fission rate, there are two types of cells in the procambium, the long one and the short one. The short cells contains starch grains just like the cells in interfasicular region.The ground meristems in interfasicular region can diffentiate and developinto new procambium strands.