| 1. Regression of shell size and weight of Dosinia laminateThe experimental material were randomly selected125Dosinia laminate in ZhuangHeregions wild. The analysis of phenotypic traits were shell length (SL), shell high (SH), shellwidth (SW), apex of shell to shell frontpart (a), apex of shell to the back of shell (b), ligamentlength (c), the weight traits live weight (W), soft body weight (MW), shell weight (SW). Usingthe correlation analysis, path analysis and regression analysis method to study the phenotypictraits affect weight traits of Dosinia laminate. Results showed that the measurement in thecorrelation coefficient between the various characters were extremely significant level (P <0.01)of Dosinia laminate. Shell length (SL) and shell height (SH) was the important phenotypic traitsof live weight (W), soft weight (MW) and shell weight (Sw). Adopt the method of stepwiseregression, the phenotypic traits of characters and the optimal regression equation wasestablishmented: MW=﹣25.653+0.399SH+0.331SL R2=0.693； Sw=﹣25.484+0.382SL+0.390SH R2=0.739；W=﹣53.576+1.208SL﹣0.347b+0.654SH R2=0.691. The resultsof this experimental can be as a Dosinia laminate provide theoretical basis for the breeding andselection breeding.2. The observation fertilization cytology and early embryonic development process of DosinialaminateThe experiment used fluorescence microscopy to observe the Dosinia laminata of fertilizedeggs in the fertilization process, which was early cleavage nuclear phase change and earlyembryonic development. The experimental results showed that the water temperature of25~26℃and the salinity was under26,the discharge fertilized eggswas round sphere of Dosinia laminate,and most of the fertilized egg was in the middle of the first meiotic division. After eggs went intothe eggs, the emissions of polar body, the combination of male and female pronucleus completefertilization. And then began to segmentation, through two cell stage, four cell stage, stage eightcells until morula stage. After morula stage began to cell division in complicate, whichthroughed the blastocyst stage, archenteron stage, trochophore stage and veliger stage. Theresearch of Dosinia laminate fertilization cytology and early embryonic development not onlyenriched the contents of the shellfish fertilization biology research, but also provided basic datafor artificial seedling raising and breeding of artificial insemination operation.3. The influence of temperature and salinity on the Dosinia laminate hatch and the impact oflarval growth to the survival.Five different temperature gradient(18、22、26、30、34℃) and six different salinitygradient (10、15、20、25、30、35)was used to analysis the influence of fertilized egg hatchabilityand the larval growth to the survival of Dosinia laminate. The results of temperature experimentshowed that the suitable incubation temperature of Dosinia laminate was26to34℃;9days afterfertilization, the highest survival rate of larvae was26℃, which was77.67±1.52%. And in whichthe larvae grow fastest, the average shell length and shell high, respectively was145.50μm and122.83μm in the9th day. So the growth of the larvae optimum temperature was22-30℃.Salinity experimental results showed that Dosinia laminate suitable hatch salinity wsa20-30;After9days fertilization, the salinity of25had the highest survival rate of larvae, which was73.33±2.89%. The salinity of25group larvae grow fastest after9days fertilization.The7th day to9th day had the fastest growth in the salinity of25.The9th day average shell length and shellhigh was144.67μm and122.83μm. The growth of the larvae suitable salinity is20to30.4. The influence on the growth of Dosinia laminate planktonic larvae in different of bait andcultivate density.The studies of two bait feeding was in three way and four different breeding density on thegrowth of the Dosinia laminate planktonic larvae. The experiment of bait results showed that thedifference between1d and3d groups of larvae growth was not significant (P>0.05). Theexperiment of5th day, the differences between groups began to appear. At the end of theexperiment, mixing cast group larvae had the maximum shell length was186.67±3.01μm whichhad the significant difference with other group (P <0.05), and the maximum growth rate was8.98μm/d. The minimum shell length in yeast group larvae was177.50±3.12μm, and the dailygrowth rate was8.07μm/d. The results of breeding density experiment showed that at the end ofthe experiment, the breeding density of5experimental shell maximum was186.66±3.01μm, andwhich was significant difference to other experiment (P <0.05). Shell length minimum of15and20experimental group were176.17±2.51μm and174.00±1.80μm. But the difference between15and10was not significant (P>0.05). |
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