甘薯(Ipomoea batatas(L.)lam)不定根根尖细微结构的初步研究

A primary study on the fine structure of theadventitious root tip of Ipomoea batatas(L. ) Lam.

顶端分生组织细胞有高的核质比，胞质中可见前质体和其它细胞器．分化的组织原细胞中，皮层原细胞较中柱原和根冠表皮原细胞内前质体增多明显．组织原细胞内的前质体均匀散布高电子密度基质，并以溢痕方式分裂．淀粉颗粒最先出现在分化早期的皮层细胞和根冠表皮细胞中．较大液泡形成先见于根冠表皮细胞原和中柱内的分化早期细胞．外皮层细胞弦向壁纤维化增厚，径向壁薄，具凯氏带结构．提示甘薯不定根尖早期的外皮层细胞可以分化为既具支持保护作用也适应代谢转运功能的单位．

he cells of apical meristem posseass higher the ratio of nucleus/cytoplasm, and proplastids and other organella can be seen in their cytoplasm. At the differentiational cells of histogen, the proplastids are increased distinctly. Moreover, the periblem cell is more than both the plerome and the calyptrogen dermatogen. These proplastids are permeated with the plastid stoma as higher electronic dence, and they are devided by the cintrictional ways. A few small particles of the starch are discovered in the protplastid first, where both of the cortical cells and the calyptricepidermic cells are differentiated at the earlier stage of development. Otherwise, the bigger vasculation have begun to show on the earlier differentiational cell of stele, and in the cells of the calyptrogen dermatogen. The tangetial wall of the exodermic cell is diposited by the fibres to become thickness, however, the radial wall is had to thin with structure of Casparian strip. In the developmental adventitious roots tip of Ipomoea batatas , the earlier exodermic cells differentiate into functional unit, which is not only to have sustainable and protective but adapts to metabolic transmission as well are prompted.