THE SOLICITATION MECHANISM OF THE CORTICAL REACTION IN HEMIBARBUS LABEO EGG

There are 1 to 4 rows and five types of cortical alveoli in the cortex of the pallas, Hemibarbus labeo egg. From inner to outer of the cortex, the diameter of cortical alveoli decreases gradually. We find a new structure named solicitation speckle at low latitude of animal polar and near micropylar apparatus between envelope of ovum and plasma membrane, in zygote of fish. The solicitation speckle is very purple in H. E, that is similar to type Ⅰ of cortical alveoli. In TEM, the solicitation speckle has not obvious bourn with envelope of ovum and plasma membrane, and no membrane around the solicitation speckle too. In SEM, the solicitation speckle looks as garrulous. During cortical reaction, the solicitation speckle plays very important initiative function. About 35s after fertilization, cortical alveolus begin to discharge from the low-latitudes of the animal hemisphere, later, the same thing happens in the near of micropylar apparatus, and then cortical reaction extends to the animal hemisphere and the vegetal hemisphere. Cortical reaction comprises latent period, developmental period, climactic period and declining period. In latent period, no cortical reaction, in developmental period, a few cortical alveolus discharge outer of the cortex, in climactic period, many cortical alveolus discharge, before discharging several cortical alveolus fuse into a big vesicle, and in declining period, type Ⅴ of cortical alveoli inner of the cortex discharges. 5min after fertilization, cortical alveoli has discharged entirely in the animal hemisphere, the residual cortical alveolus will entirely discharge in 8min. We think cortical reaction is a fulminic chain reaction abducted by solicitation speckle and type Ⅰ of cortical alveoli, the outer cortical reaction can accelerate the inner cortical reaction. While cortical alveoli discharges in batches, the plasma membrane has been reorganized time after time. No cortical alveoli below the micropylar tube where sperm enter into, this suggests it is finite that the cortical reaction prevents polyspermy.