桑叶细脉中伴胞的超微结构研究  

Ultrastructural Study on Companion Cells in Leaf Minor Veins of Morus alba

作　　者：郭庆慧[1,2] 刘林[2] 

机构地区：[1]临沂大学图书馆,山东临沂276005 [2]临沂大学生命科学学院,山东临沂276005

出　　处：《植物科学学报》2013年第1期57-63,共7页Plant Science Journal

基　　金：山东省自然科学基金(ZR2011CL002);临沂大学科研计划项目(HX09104)

摘　　要：为了解桑叶细脉中伴胞的超微结构,采用透射电子显微技术对桑叶细脉中伴胞进行观察,着重伴胞与相邻细胞界面上胞间连丝发生频率。结果表明,(1)伴胞含丰富细胞器,细胞壁光滑,无壁内突;(2)伴胞细胞壁上具有大量胞间连丝,胞间连丝通常聚集,并常发生分枝;(3)伴胞与不同类型细胞界面上的胞间连丝发生频率有差异,伴胞-维管束鞘细胞界面上发生频率为25.12±1.83个/μm2,伴胞-伴胞界面上20.18±1.7个2/μm2,伴胞-维管薄壁细胞界面上5.42±0.6个/μm2。基于上述观察,认为桑叶细脉中的伴胞属于1-2a型,韧皮部装载途径属于共质体类型。The transfer of photosynthates from mesophyll cells to sieve element-companion cell complex is called phloem loading. Loading mechanisms are closely related to the ultrastructural features of companion cells. To understand the ultrastructural features of companion cells in leaf blades of Morus alba, companion cells in minor veins were characterized by transmission electron microscopy. We demonstrated that （a） companion cells had smooth walls and con- tained a whole set of organelles such as nucleus, vacuoles, mitochondria, plastids, and ribo- somes. （b） Many plasmodesmata occurred at the interfaces between companion cells and adjacent cells. Plasmodesmata usually existed in groups and were often branched. （c） Plas- modesmatal frequencies were 25.12 _＋ 1.83 pd/iJm2 at the interface between companion cells and bundle sheath cells and 20. 18 ＋ 1.72 pd /um2 at the interface between neighboring companion cells, in contrast to 5.42 ＋ 0. 6 pd/#m2 at the interface between companion cells and vascular parenchyma cells. Based on that companion cells in minor veins in leaf therefore the phloem loading pathway was these ultrastructural observations, it was supposed blades of M. alba be classified as type 1-2a, and symplasmic.

关 键 词：桑 伴胞 细脉 超微结构 

分 类 号：Q945[生物学—植物学]