【摘要】 何首乌根异常构造的发生,是在根的初生构造已完成以及次生构造开始形成,形成层不断地向内分裂分化呈次生木质部,向外分裂分化呈次生韧皮部的同时,中柱鞘细胞连续分裂呈数层,其外层转化成木栓形成层,进而形成周皮;木栓形成层不断向内分裂分化成栓内层,此时可称次生皮层。在次生皮层中,部分薄壁细胞恢复分生能力,陆续地形成1～多个圆环状异型维管束。更多还原

【Abstract】 The development of heterogeneous structures of the root tuber of polygonum m- ultiflorum takes place at the time when its primary structures have formed and its secondary structures begin developing,and when the cambium dontinue dividing its cells inwards,thus forming the secondary xylem and outwards,thus forming the se- candary phloem.And at the same time,the pericycle cells continue dividing into several strata,and its outer cells turn into the phellogen.The cells of the phellogen towards outside differentiate as phellem,and towards inside as phelloderm or secon- dary cortex.Partial parenchyma cells in the secondary cortex resume them meriste- -matic activitg,thus foming one or more circular heterogeneous vascular bundles.更多还原