【摘要】 大白菜是子叶出土幼苗，子叶节区下部具木质部中部凹缢的中始式二原型单中柱，特称芸苔型（Ｂｒａｓｓｉｃａｔｙｐｅ）。作者在大白菜幼苗子叶节区中部也发现了属于管状中柱范畴的疏隙中柱阶段（ｓｏｌｅｎｏｓｔｅｌｅｓｔａｇｅ），从而进一步证明管状中柱和疏隙中柱在种子植物体内并非毛茛科某些属（Ｇａｒｉｄｅｌａ、Ｎｉｇｅｌａ）所特有，至少在十字花科的芸苔属（Ｂｒａｓｉｃａ）也存在。更多还原

【Abstract】 Brassica pekinensis has an epigaeous seedling, and there is a xylem in the low part of Cotyledon node zone, and the mesarch and diarch hoplostele which is sunken in the middle part is termed Brassica type in this paper. The author also finds the solenostele stage that belongs to siphonostele in the middle part of CNZ. This discover further prove that solenostele and siphonostele are not only the features of some genus of Ranunculaceae in the body of spermatophete, and they exist in the Brassica of Cruciferae, too.更多还原