| The oyster is China’s important farming shellfish, The total first-yearresident in shellfish aquaculture production, Triploid oyster due to its poorfertility, fast growth, the characteristics of good quality, and many other is betterthan that of diploid and become an important part of the oyster breeding, Favoredby consumers. At present, the main there are two ways to obtain triploid oysters.One is the physical and chemical methods inhibiting normal fertilized eggemissions of the second polar body, One is the use of diploid and tetraploidhybrid produces100%of the triploid oysters. Domestic production of triploidoysters first way to use more. Using6-DMAP, physical and chemical methodssuch as induction temperature shock. In this study the main varieties of oystercultivation in China---Pacific oyster (Crassostrea gigas) and nearly river oysters(Crossostrea ariakensis). Attempt to salt in either high or low salt restrain thefertilized egg2release of polar body, induct triploid oysters. This method is safenon-toxic, low prices, Suitable for oysters triploid industry production, has abroad application prospect.The research mainly divided into the following two most:1．High salt induced triploid Pacific oystersIn this study, First by fluorescent staining method micro observation ofPacific oyster sperm egg fertilization and early embryo development, found23℃temperature conditions, Near the river oysters in25minutes after fertilization ofthe first polar body (PB1) and this helps polyploid induction time accurately.Secondly, For the first time using high salt inhibition of triploid Pacific oystereggs the body to release2, Explore the best induced high salt inducing triploidoptimum conditions. Under the condition of water temperature is25℃, Indifferent fluid of high salt treatment(Salinity is respectively40,45,50,55,60,65, 70,75,80, PPT), In the different processing time, When30%,50%appear PB1for the first time,and50%appear PB2for the first time,put the Pacific oystereggs in the treatment fluid, Continuous processing10,15,20,25min,thenput the fertilized eggs in normal seawater(Salinity is35PPT) hatch, Using300mesh sieve screen filtering seawater (D-type larvae, Through the flow cytometryinstrument times sex determination, To determine optimum induction conditions.Through the analysis of induction rate and comprehensive evaluation index showsthat, high salt induced the best parameters for the Pacific oyster polyploidy is:Salinity65, Processing time of50%PB, Processing time of50%PB. Accordingto the optimum condition, When the fertilized egg appeared50%PB1, In65thehigh salt water salinity treatment fertilized egg20min, Larvae of triploidinduction rate was65.53%.By fluorescence observation, The Pacific oyster eggs in about25min afterfertilization the first polar body, All the first polar body eduction is about30minutes. Which in use can be determined in the process of high salt induced thePacific oyster triploid induced timing.Lastly, On the use of high salt induced triploid oysters (eight months) ofchromosome observation, Discovered the chromosome loss phenomenon, That isaneuploid phenomenon. The diploid chromosome deletion of level is2n-1and2n–2, The chromosome number is18or19, The lack of triploid level2kinds offindigs,3n-1and23n-4,the number of chromosomes is29and26. Phenomenon isthe emergence of aneuploidy may be related to the instability of polyploidychromosomes.2. Low salt triploid induced near river oystersLow impact on nearly jiang oyster extract egg and salt water to dissect theboiled eggsIn natural seawater according to certain proportion in distilled water,Preparation of salinity is5,10,15,20,25,30seawater, Sperm of drop in differentsalinity of seawater. Timing of the activities of sperm. The results show that lowsalt water had significant effect on the activity of sperm. Sperm survival time shortened with lower salinity, When the salinity in10and under, Within3minsperm lose exercise capacity, With the increase of salinity, sperm survival timeprolonged, When salinity is25and30, Sperm active within2h,3h activitydecrease, but there are still more than40%of the active sperm.Salinity of oyster eggs had significant effect on the morphology andfertilization ability. The eggs were soaked in different salinity of seawater after10min, Found the egg shape size change, The egg diameter size and the trend ofpresent a negative correlation between salinity, After soaking25min, Resultsshowed that fertilization experiment, The fertilization rate and salinity showed apositive correlation between the trend, Egg fertilization rate rapidly reduce withlower salinity, When salinity is lower than10PPT, fertilization rate is0.Normal seawater immersion of oyster eggs have promote role. Soaking timein0.5-1.5h. Oyster eggs has higher fertilization rate, But again later extended to2h after soaking time, appear the phenomenon of the fertilization rate reduce.The experimental results show that near the river the oyster body anatomy eggsoutside medium suitable for the most timely between0.51.5h.Low permeability induced near river triploid oystersIn20%30%,40%and50%respectively, and60%-70%of the fertilizedegg appeared PB1, Using different low salt (salinity is6,8,10,12,14,16)processing near jiang oyster eggs10,15,20min, Then put the fertilized egg into30normal filtering seawater salinity is hatching. When hatched D-type larvae.collecting larvae, after DAPI fluorescent dye, Using flow cytometry instrumentfor ploidy determination, Through the analysis of induction rate andcomprehensive evaluation index shows that, Low salt induced near the bestparameters for oysters polyploid river: salinity is8, Processing time is40%-50%PB1fertilized egg, The treatment duration of15min. According to theexperiment it is concluded that the optimal conditions, When the fertilized eggappeared40%50%PB1, Low salt water treatment fertilized eggs with salinity is6for15min，Larvae of triploid induction rate was89.03%，The hatching rate was 80.23%，the comprehensive evaluation index is71.43。The results showed thatlow permeability induced for oysters jiang is a very effective method of triploidinduction，It has good application prospect。... |
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