《植物生理学报》 2016, 52(10): 1546-1554
摘 要：以‘巨峰’葡萄为试材, 研究了根域限制对果实可溶性糖积累的影响, 并采用透射电镜技术对发育过程中果实韧皮部及其周围薄壁细胞的超微结构进行了系统观察。结果表明: 根域限制可以提高‘巨峰’葡萄果实中可溶性糖含量, 糖分积累主要发生在第2次快速生长期; 根域限制增加了筛管和伴胞、筛管伴胞复合体和薄壁细胞之间的胞间连丝密度; 根域限制下筛管体积变小, 但伴胞体积增大, 而且伴胞中的细胞质浓密, 线粒体、内质网、囊胞等细胞器丰富; 在果实的第2次快速生长期, 根域限制和对照细胞均表现出衰老降解的特点, 但根域限制伴胞中仍存在完整线粒体, 筛管伴胞复合体和周围薄壁细胞中发现大量的小囊胞, 根域限制下小囊胞数目高于对照。以上结果表明根域限制改变了‘巨峰’果实周缘维管束韧皮部细胞的超微结构, 这些改变有利于光合产物在果实中的积累。
关键词：葡萄果实; 根域限制; 可溶性糖含量; 韧皮部; 超微结构
Corresponding author: LI Bo; E-mail: firstname.lastname@example.org
Abstract:Effect of root restriction on sugar accumulation of the ‘Kyoho’ grape berry was studied. The ultrastructure of phloem and its surrounding parenchyma cells in the developing grape berry produced under root restriction or without (control) was systematically investigated through transmission electron micros-copy. The results showed that root restriction can increase the content of soluble sugars in grape berries and sugar accumulation mainly occurring in the second rapid growth phase of the grape berry. Root restriction increased the number of plasmodesmata between sieve elements (SE) and companion cells (CC) and the plasmodesmata density between the SE/CC complex and phloem parenchyma cells. Sieve elements in fruit produced under root restriction were smaller than those from the control treatment, but companion cells were bigger. Meanwhile there was denser cytoplasm in the companion cells produced under root restriction having more abundant mitochondria, endoplasmic reticulum, and vesicles than in control fruit. During the second rapid growth phase of the grape berry, all cells produced under root restriction or without presented an obvious process of senescence and degeneration, but the mitochondria of berry under root restriction remained intact and numerous. Lots of vesicles under root restriction or without were observed, and the vesicles of berry under root restriction became denser than in the control treatment. These results demonstrated that root restriction changed the ultrastructure of phloem and its surrounding parenchyma cells, which explained the photosynthate accumulation in the ‘Kyoho’ grape berry observed under root restriction.
Key words: grape berry; root restriction; soluble sugar content; phloem; ultrastructure
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