芝麻茎端结构及茎初生组织分化的研究

芝麻的茎端具有明显的原套、原体结构和细胞组织学的分区界线。这种结构特点在双间隔期的晚期表现得最为突出。茎端的高度和宽度随着叶龄的增加而略有加大，但高、宽比则基本上无变化、茎的原表皮由原套的最外层细胞分化发育而来，皮层母细胞由周缘区的较外侧及原套的内层细胞分化发育而来，髓母主要由肋状分生组织区的细胞产生，但也有少部分来源于周缘区的内侧细胞。原形成层在顶端分生组织之下叶原基起源的地方发生。在某一原形成层束内，最早分化的是原生韧皮部，其次是原生木质部，后生木质部分化最晚。

STUDIES ON THE STRUCTURE OF THE SHOOT APEX AND DIFFERENTIATION OF THE PRIMARY TISSUEOF STEMIN SESAMUM INDIUM

The funica,the corpus and the cyto-histological zones can be distinguished easily in the shoot apex of Sesamum indium,especially those at late plastochronic stage during a double plastochron. The height and width of shoot apex are little increase during the number of leaf increases,but the ratio of height and width don't change.the original epidermis arises from the outermost layer of tunica, the original cortex arises from outermore layer of peripheral zone with inner layer of tunica. The original pith arises from the cells of rib meristem,the little cell arise from the inner layer of peripheral zone.The procambium continuously develop to the apex after it arises from the place where the leaf primordia originates from below the apical meristem.In the procambium bunch,the protophloem is first derived from procambium, the protoxylem is secondary derived from procambium and the last is metaxylem.