甘蔗茎尖原生分生组织区域化

Zoning of sugarcane stem tip protomeristem

甘蔗茎尖原生分生组织是甘蔗地上部分一切形态组织的发源中心,通过对6个不同茎径甘蔗品种4个不同营养发育时期的茎尖原生分生组织显微和超微结构观察研究发现:甘蔗茎尖原生分生组织呈半卵型结构,明显分为原套原始细胞区、原体原始细胞区、周缘分生细胞区、髓分生区,其区域化符合原套-原体学说。原套原始细胞区为最外一层细胞,原套细胞之间胞间连丝丰富,而原套与原体细胞之间胞间连丝极少,细胞以垂周分裂为主,扩大原生分生组织表面积;原体位于原套下的分生组织的中央区域,细胞可以进行各个方向的分裂,不断增加体积,原体原始细胞区呈一个球体;周缘分生区位于原套、原体下方两侧,细胞活跃产生叶原基和原形成层细胞;髓分生区细胞位于原体下方周缘分生区内侧,细胞横向分裂纵向排列,使甘蔗茎伸长。

All organization of sugarcane stem and leaf origined from stem tip protomeristem. The stem tip protomeristem of six sugarcane cuctivars at four different developing stages was investigated using microstructural and ultrastructural techniques. The results showed that sugarcane stem tip protomeristem had four zones：tunica-primary cell zone,corpus-primary cell zone,peripheral meristem zone and pith zone. The tunica-primary cell zone had only one layer of tunica cells and many of plasmodesmus crossed between the tunica-primary cells,but few plasmodesmus crossed between the tunica-primary cells and the corpus-primary cells. Most of tunica-primary cell were anticlinal division in order to enlarge protomeristem superficial area. The corpus zone located in the central region of the meristem below the tunica,where the cell divisions were in all directions to increase both the width and length of the apex. The corpus-primary cell zone appeared to be a sphere. The peripheral meristem zone located the two sides under the tunica-primary and the corpus,which cells were very active and generate phyllopodium and protocambium cells. The pith zone was at the inner side of peripheral meristem under the corpus,and the cell division was transverse and end-to-end arrangement to elongate the stem.