摘要
【目的】果实韧皮部胞间连丝分布特点决定韧皮部同化物卸载途径类型,为了解‘富有’柿果实膨大期韧皮部胞间连丝分布特点,【方法】采用透射电子显微技术对膨大期果实韧皮部做超微结构研究,统计不同类型细胞界面上胞间连丝发生频率。【结果】结果表明,柿果实维管束没有维管束鞘,直接与果肉细胞连接,韧皮部由筛管分子、伴胞和维管薄壁细胞构成,筛管-伴胞界面、伴胞-维管薄壁细胞界面、维管薄壁细胞-维管薄壁细胞界面以及维管薄壁细胞-果肉细胞界面上都存在胞间连丝,伴胞-维管薄壁细胞界面上的胞间连丝发生频率约为维管薄壁细胞-果肉细胞界面上的一半。【结论】据此认为,‘富有’柿果实韧皮部伴胞与维管薄壁细胞界面上分布有中等数量的胞间连丝,显示韧皮部卸载途径为共质体类型。
[Objective]Phloem unloading pathways are categorized into symplasmic and apoplasmic types. The types of phloem unloading pathways are mainly determined by the distribution of plasmodesmata in the phloem. The existence of plasmodesmata at the companion cell-vascular parenchyma cell interface may indicate symplasmic pathway of phloem unloading, and the absence of plasmodesmata signifies that the pathway of phloem unloading is apoplasmic. In order to understand the distribution of plasmodesmata in the phloem in developing young fruits of persimmon, [Method]transmission electron microscopy was applied to characterize the phloem in enlarging fruits of ＇ Fuyu＇, and calculate the plasmodesma frequency at interfaces between different cell types. [Result]Results showed that vascular bundles in young fruits did not have bundle sheath, so vascular parenchyma cells directly contacted flesh cells. The phloem consisted of sieve elements, companion cells and vascular parenchyma cells. Plasmodesmata occurrd at all interfaces including sieve element-companion cell interface, companion cell-vascular parenchyma cell inter- face, and vascular parenchyma cell-flesh cell interface. The plasmodesma frequency at the companion cell-vascular parenchyma cell interface was half of that at the vascular parenchyma-flesh cell interface, indicating a 1-2a type of companion cell. [Conclusion]It is concluded that there is a moderate number of plasmodesmata at companion cell-vascular parenchyma cell interface and therefore phloem unloading pathway is symplasmic type in enlarging fruits of persimmon ‘ Fuyu＇.
出处
《果树学报》
CAS
CSCD
北大核心
2012年第5期872-876,共5页
Journal of Fruit Science
基金
临沂大学科研基金(HX09104)
临沂市科技局计划项目(200101)
山东省教育厅科研计划项目(J01H51)
山东省自然科学基金(ZR2011CL002)
