Parent Culture and Early Individual Development of Perinereis Aibuhitensis under the Cultivation Condition with Gracilaria Tenuistipitata
|School||Guangdong Ocean University|
|Keywords||Perinereis aibuhitensis temperature parents culture gonad development embryonic development morphological character|
In this paper the effect of temperature on parents culture, gonadal development, embryonic and early individua development of Perinereis aibuhitensis were studied under the cultivation condition with Gracilaria tenuistipitata. The main results are as follows:1. The result showed that under cultivation condition with Gracilaria tenuistipitata, temperature had a significant effect on parents survival rate, metamorphic rate, absolute fertility and body weight of Perinereis aibuhitensis(P<0.05).When temperature was 22℃or 24℃, survival rate reached to 82.0%-86.0%, metamorphic rate was 44.0%, body weight was 5.22g, absolute fertility got to 23.17 million grains, all of them were observably higher than other experimental groups. Relative fertility reached to 4.27-4.44 million grains per gram and gonad ratio was 64.06%-67.04% in the temperature range of the experiment, there were no significant difference among groups(P>0.05). The optimum temperature of Perinereis aibuhitensis parents culture was 22℃-24℃.2. Depending on the morphological characteristics, internal structure and diameter of Perinereis aibuhitensis oocyte, four successive phases of an oocyte were described as stage I-Oogonium, stage II-Primary oocyte, stage III-Primary oocyte (Previtellogenesis, mid-vitellogenesis, Postvitellogenesis), stage IV-Mature oocytes (Procolloidal membrane stage,Postcolloidal membrane stage). Female gonad was divided into five stages: Ovary I, Ovary II, Ovary III, Ovary IV, Ovary V on the basis of the quantity changes of eggs in each stage and morphological changes of other structure in coelom.3. According to the size, morphology and location of Perinereis aibuhitensis spermatocyte, the development of spermatogenesis was divided into five stages: Spermatogonia stage, Primary spermatocyte stage, Second spermatocyte stage, Spermatic stage and Sperma stage. depending on the morphology, quantity changes of sperma and morphological changes of other tissues and organs Male gonad was also divieded into five stages: Spermary I, Spermary II, Spermary III, Spermary IV, Spermary V.4. Each period of gonadal mainly contained the same period of germ cell and sometimes included different periods of germ cell, and the rate of development was not indentical.5. The mature egg appeard mesolecithal egg and had lots of oily granules.The embryonic development of Perinereis aibuhitensis could be divided into seven stages: cleavage blastoderm, gastrule, pro-trochophore, late trochophore, nectochaete (3- setiger juvenile in the oolemma 1 day old 3-setiger parapodium juvenile, 2 day old 3-setiger parapodium juvenile, 4-setiger parapodium juvenile, 5-setiger parapodium juvenile) and setiger juvenile.6. The oosperm of Perinereis aibuhitensis was spiral cleavage.when the water temperatue was 20℃, trochophore appeared after 21h, larva began to ingest after 50h, 5-setiger nectochaete seate became short, at the same time the larvar began to grovel, and the life habit began to correspond with adult.7. The condition with Gracilaria tenuistipitata, take advantage of the plant productivity, optimize the cultivation environment and provide excellent habitat for Perinereis aibuhitensis. Perinereis aibuhitensis adapt the cultivation environment with higher temperature. The gonad developed completely, fast and normally.The parents product the oosperm which has complete embryonic development and complete individual development. The condition with Gracilaria tenuistipitata has highly developing potential as cultivation model of Perinereis aibuhitensis.