摘要
蚕豆(Vicia faba L.)成熟胚囊超微结构及ATP酶定位的研究表明:卵细胞的合点端无细胞壁,细胞核位于合点端,其核膜上具较多核孔。细胞质主要分布于核的周围,其中所含线粒体及高尔基体的量较少,具淀粉粒及脂滴。助细胞的合点端亦无细胞壁,而且此处具有助细胞向中央细胞外突的泡。助细胞两侧与中央细胞间存在胞间联丝。助细胞的核位近珠孔端,形状不规则。细胞质中各种细胞器含量丰富,丝状器的结构不均一。中央细胞质较少,但细胞器含量丰富,具淀粉粒和脂滴。两个极核多具核仁液泡且核膜已部分融合。卵细胞及中央细胞质中的内质网具ATP酶反应。胚囊壁为深浅不同的嗜锇层组成的较致密结构,合点处具壁内突。其外的珠心细胞特化成长形或楔形,细胞间隙中有一条条明显的ATP酶反应颗粒带,可能与营养运送有关。
Studies of ultrastructure and ATPase localization of the mature embryo sac in Vicia faba L. show that the egg cell has no cell wall at the chalazal end, it has a chalazally located nucleus and a large micropylar vacuole. There are many nuclear pores in the nuclear membrane. The cytoplasm is restricted around the nucleus. Dictyosome and mitochondria are few. There are some starch grains and lipid grains in the egg cytoplasm. There are no obvious differences between two synergids. No cell wall is seen at the chalazal end either, but there are some vesicles which project to vacuole of the central cell and fuse with its vacuolar membrane. Plas-modesmata connections occur within the synergid wall where it is adjacent to the central cell. The synergid has a micropylarly located nucleus and a chalazal vacuole, the nucleus is irre- gularly shaped. The synergid cytoplasm is rich in organelles. The filiform aparatus is of relatively heterogeneous structure. The central cell is occupied by a large vacuole and its cytoplasm is confined to a thin layer along the empryo sac wall, but is rich in various organelles, starch grains and lipid bodies. Nucleolar vacuoles are often present two polar nuclei. The nuclear membranes of two polar nuclei have partly fused. ATPase reactive product was located obviously at the endoplasmic reticulum in cytoplasm of the egg cell and central cell. The embryo sac wall consists of different density of osmiophilic layer. There are some wall ingrowths in chalazal region of the embryo sac. The long-shaped and cuneate cells of chalazal region are peculiar. Special tracks of ATPase reactive products are visible at their intercellular space which may be related to transportation of nutrients.
关键词
蚕豆
超微结构
ATP酶
胚囊
Vicia faba
Mature embryo sac
Ultrastructure
ATPase
