毛青藤茎的发育解剖学研究

毛青藤茎顶端的原生分生组织由原套和原体组成，其行生细胞形成初生分生组织──原表皮、原形成层和基本分生组织。初生分生组织的衍生细胞分化形成茎的初生结构，包括表皮、皮层、维管束和髓。随着茎的继续发育，维管形成层开始活动，由束中形成层产生次生韧皮部和次生木质部分子，而束间形成层仅产生薄壁组织细胞形成宽的射线。在原生韧皮部筛管分化成熟的过程中，韧应部外方仍保留1—2层原形成层细胞，以后，它们分裂为多层纤维原始细胞，在次生结构形成时，这些细胞的细胞壁加厚，形成初生初皮纤维。茎始终未产生用皮。

DEVELOPMENTAL ANATOMY ON THE STEM OF SINOMENIUM ACUTUM VAT. CINEREUM

Promeristem was composed of two layers of tunica cells and a group of corpus cells,with the development of promeristem, the primary meristem, including protoderm,procambium and ground meristem was formed at the apex of the shoot. The primarymeristem differentiated into primary structure consisting of epidermis, vasctllar system,cortexand pith. With the progressive development of stem,the activity of vascular cambiumbegan,the fascicular cambium differentiated into secondary xylem and secondary phloem,while the interfascicular cambium only differentiated into wide ray of parenchymatissue. On developing of sieve tube members of protophloem,one or two layers ofprocambium cells around the protophloem turned into phloem fiber initials through dividing.When the secondary structures were formed,the wall of those cells was gradullythickened and primary phloem fibers were formed. But the cork was not found to form in thestem from beginning to end in its whole life.