蝶蛹金小蜂卵黄发生前后脂肪体和卵泡的超微结构

Ultrastructures of fat body cell and follicle prior to and during the vitellogenesis of Pteromalus puparum

用透射电镜观察了蝶蛹金小蜂Pteromaluspuparum卵黄发生前后脂肪体超微结构的变化,同时观察了卵巢中不同发育时期卵泡的超微结构.卵黄发生前(蛹期)的脂肪体细胞含有大量蛋白颗粒和线粒体,但未见粗面内质网,早期蛹脂肪体细胞中可见多囊泡体;卵黄发生期(隐雌成蜂～5日龄雌成蜂)的脂肪体细胞内粗面内质网和线粒体均较为丰富.在新形成的卵泡中,卵母细胞内尚无卵黄蛋白沉积,但脂滴较多;在 级和 级卵泡中,卵母细胞中沉积有较多的卵黄体和脂滴,且 级卵泡中的卵黄体明显大于 级卵泡; 级卵泡中,卵母细胞内充满卵黄体和脂滴,并已形成卵壳.

The ultrastructures of fat bodies before and during vitellogenesis and of follicles at different developmental stages in the parasitoid Pteromalus puparum were studied by electron microscope. At previtellogenic stage (that is, at pupal stage), large amounts of protein granules and mitochondria were present in fat body cells, but no rough endoplasmic reticulum (RER) could be observed. However, there were large amounts of RER as well as mitochondria in fat body cells, and large lipid droplets also occurred during vitellogenesis (that is, the period from pharate adult stage to 5 d after emergence). In the newly formed follicles, there were lots of lipid droplets but no yolk granules in the oocyte. In the grade Ⅰ and grade Ⅱ follicles, lots of yolk granules accumulated in oocytes besides the lipid droplets. In addition, yolk granules in grade Ⅱ follicles were obviously larger than those in grade Ⅰ follicles. In the grade Ⅲ follices, oocytes were filled with yolk granules and lipid droplets, and eggshells had been formed.