无孢子生殖胚囊助细胞的研究

Study on Synergid in Aposporous Embryo Sac

为了解无孢子生殖胚囊助细胞的特点,用透射电子显微镜对无孢子生殖植物非洲狼尾草无融合生殖胚囊的助细胞进行了研究.结果表明,助细胞壁产生无数突起,伸入细胞质形成巨形丝状器,呈圆锥形,细胞质深入丝状器内部,这一结构对引入花粉管有利;细胞含在量线粒体、高尔基体、核糖体等细胞器,以丝状器周围最为丰富,显示出旺盛的代谢活动;具有丰富的贮藏物质,先是以淀粉形式积累,然后淀粉转化为脂类物质,以脂滴形式存在,细胞解体后供卵和中央细胞利用.无孢子生殖胚囊肋细胞的结构特点与有性生殖胚囊助细胞一致,其存在为花粉管进入胚囊提供通道,并为胚囊其它成员发育提供营养.

To determine the ultrastructural features of synergid in aposporous embryo sac, we characterize the synergid in the apomictic embryo sac in the aposporous species Pennesetum squmulatum using transmission electron microscope. It is found that the synergid has a large conical filiform apparatus, which consists of a mass of wall projections extending deep into the cytoplasm, and versa cytoplasmic tunnels penetrating deep into the filiform apparatus. The filiform apparatus play a role in leading the pollen tube into embryo sac. The synergid contains a lot of mitochondria, dictysomes, and ribosomes, implying active metabolism. There is rich storage, which originates as starch and then the starch transforms into lipid. The storage provides nutrition for further development of egg cell and central cell. The structural feature of synergid in the aposporous embryo sac is analogous to that in the sexual embryo sac.