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郭庆慧, 刘林. 桑叶细脉中伴胞的超微结构研究[J]. 植物科学学报, 2013, 31(1): 57-63. DOI: 10.3724/SP.J.1142.2013.10057
引用本文: 郭庆慧, 刘林. 桑叶细脉中伴胞的超微结构研究[J]. 植物科学学报, 2013, 31(1): 57-63. DOI: 10.3724/SP.J.1142.2013.10057
GUO Qing-Hui, LIU Lin. Ultrastructural Study on Companion Cells in Leaf Minor Veins of Morus alba[J]. Plant Science Journal, 2013, 31(1): 57-63. DOI: 10.3724/SP.J.1142.2013.10057
Citation: GUO Qing-Hui, LIU Lin. Ultrastructural Study on Companion Cells in Leaf Minor Veins of Morus alba[J]. Plant Science Journal, 2013, 31(1): 57-63. DOI: 10.3724/SP.J.1142.2013.10057

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

  • 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.

     

    Abstract: 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 contained a whole set of organelles such as nucleus, vacuoles, mitochondria, plastids, and ribosomes. (b) Many plasmodesmata occurred at the interfaces between companion cells and adjacent cells. Plasmodesmata usually existed in groups and were often branched. (c) Plasmodesmatal frequencies were 25.12 ± 1.83 pd/μm2 at the interface between companion cells and bundle sheath cells and 20.18 ± 1.72 pd /μm2 at the interface between neighboring companion cells, in contrast to 5.42 ± 0.6 pd/μm2 at the interface between companion cells and vascular parenchyma cells. Based on these ultrastructural observations, it was supposed that companion cells in minor veins in leaf blades of M. alba be classified as type 1-2a, and therefore the phloem loading pathway was symplasmic.

     

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