| Pike-perch (Sander lucioperca(Linnaeus)) with wide-temperature resistant, fast growth, excellent resistance to salts, disease resistance, have become popular in International aquatic products trade market for their deliciousness, high values of nutrition and meat quality. The embryonic and larval development of pike-perch was observed, in order to know its biological characteristics. The result will be used in increasing its hatchability and fry quality. The karyotype analysis and chromosome banding of pike-perch were studied for its genetic diversity, population identification and FISH. It will provide basis for Cyrogenetics and genomic physical map. The main results are as follows:1. A successive observation was conducted to study the embryonic larval and juvenile development of pike-perch. The results showed that the eggs, measuring 0.90-1.01mm in diameter, were sticky and almost spherical in shape, with a pale yellow yolk and 1.2mm after absorbing water. Hatching occurred 94h after fertilization at 16.0-17.2℃. The embryonic development can be divided into 24 stages: fertilized egg , one cell stage, cleavage stage, 2-cell stage, 4-cell stag, 8-cell stage, 16-cell stage, morula stage, early blastula stage, mid blastula stage, late blastula stage, early gastrula stage, mid gastrula stage, late gastrula stage, neurula stage, closure of blastopore stage, body segment appearance stage, optic rudiment stage, optic vesicle stage, caudal fin formation stage, lens formation stage, muscular contraction stage, otolithes formation stage, heart pulsation stage, hatching-out stage. According to the formula K=N (T-C) , the average temperature and hatch time were analysis with statistics. Speed of embryonic development and water temperature was very closely related. It was calculated that the newly hatched larvae's lowest temperature is about 7.55℃, and the sum calculated temperature 903.02℃·h is necessary. The larval development of pike-perch can be divided into 5 stages: hatching stage, xanthic eye stage, melanoid eye stage, one chamber air bladder stage, exhaustion of yolk stage.2. Use the whole culture medium of RPMI1640 to culture the blood cell in vitro. With researching the content of colchicines and permeating time, establish a set of mature experimental method to cultivate the blood lymphocytic cell and prepare chromosome of pike-perch. The result showed that the blood cell 0.2ml was cultivated in culture medium 5ml of RPMI1640 (RPMI 1640 : FBS=4:1; PHA concentration is 4 ug/ml; Penicillin, streptomycin, kanamycin each concentration is 100 IU/ml ) under a temperature of 25℃for 72h. Colchicines were added until it reached concentration of about 0.2ug/ml working for 3-5h before the end of cell cultivation. And the lymphocytes were permeated for 50min with KCl. The good chromosome specimens were prepared by the routine methods of hypotonicity, fixing and coloration.3. Metaphase chromosome specimens of pike-perch were prepared from short-term culture of peripheral blood lymphocytes with air-drying technique. It diploid chromosome number is 2n=48. The karyotype is compose of 2m, 10sm, 10st,12t, NF=60. The C-banding, NOR banding distribution were analyzed in chromosomes of pike-perch.The chromosomes of pike-perch were stained according to the method of Howell (1980) that was slightly modified. The result showed that 2 Ag-NORs bands were observed in these 2 species in their metaphases respectively. The position of nucleolus organizer regions of pike-perch was situated on the terminal region of short arm of the subteloeentrie chromosomes. The number of Ag-NORs showed polymorphism in different cells.The nucleus were stained by the Ag-staining, 53.99% of then have one nucleolus and 45.62% of nucleus have two nucleoli. All the chromosomes of pike-perch have C-bands. The C-bands of homologous chromosome are approximate the same in size, location and intensity of colouring. C-banding of pike-perch mainly distributed at centromeres, interstitial and terminal regions. |
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