盐度对香港巨牡蛎♀×葡萄牙牡蛎♂杂交子代稚贝的影响及杂种优势分析

Effect of Salinity on Heterosis for Hybrid Juveniles Between Crassostrea hongkongensis♀× C. angulata♂

本研究以香港巨牡蛎(Crassostrea hongkongensis)♀×葡萄牙牡蛎(C.angulata)♂杂交牡蛎稚贝HA及香港巨牡蛎自繁组HH和葡萄牙牡蛎自繁组AA为研究对象,采用盐度渐变法研究了盐度胁迫下杂交牡蛎稚贝的生长存活及杂种优势,并通过测定抗氧化酶活性分析了杂交牡蛎的抗逆性。研究表明,稚贝HA与HH的存活适宜盐度均为15~35,HH的存活适宜盐度为20~35;HA与HH的最适生长盐度为20~30,AA的最适生长盐度20~35。存活上,HA仅在盐度35条件下产生不显著的杂种优势(H>0,hp<1);生长上,HA在盐度20~30之间具有一定的生长优势(H>0),但未达到显著水平(hp<1);增重上,在盐度25~30间存在一定的增重优势(H>0)。盐度25胁迫下,SOD、POD、T-AOC和胃蛋白酶活性先升高后降低,并于48 h内趋于稳定;盐度15胁迫下,各酶活性的变化幅度大且无明显的变化规律,T-AOC升高幅度大且48 h时显著高于对照组,而SOD与POD在48 h显著低于对照组。未受胁迫时,杂交稚贝HA的SOD、POD和胃蛋白酶活性均显著高于稚贝HH和AA(P<0.05),且具有显著的杂种优势(H>0,hp>1),杂种优势最高可达206.461%;HA的T-AOC介于两者之间,表现出一定的杂种劣势。研究结果表明,杂交牡蛎在生长和增重上具有一定的杂种优势,在抗逆性上显著优于亲本。

The experimental groups HH(C.hongkongensis),HA(C.hongkongensis♀×C.angulata♂),AA(C.angulata)were produced in this study,and the method of salinity change was used to study heterosis of juveniles at different salinities(10,15,20,25,30,and 35),and analysis of the resistance of juveniles by measuring antioxidant enzyme activity.The results showed that the suitable survival salinities of HA,HH and AA were 15~35,15~35,and 20~35;The optimum growth salinities of HA,HH and AA were 20~30,20~30 and 20~35.In terms of survival,HA produced insignificant heterosis only at 35,and there was a certain growth advantage at 20~30,but no significant difference;In addition,the advantage of weight gain was observed at 25~30.Activities of SOD,POD,T-AOC and pepsin increased first and then decreased,and eventually stabilized within 48 hours under the condition of 25.Under the stress of 15,there was no obvious change in the activity of each enzyme,which shown that the activity of T-AOC was significantly higher than that of the control group at 48 h,while the activity of SOD and POD were the opposite.The activities of SOD,POD and pepsin of HA were significantly higher than that of juvenile HH and AA under normal physiological conditions,and HA had significant heterosis,which was up to 206.461%.However,the activity of T-AOC was between HH and AA,showing a certain hybrid disadvantage.In general,hybrid oysters had certain heterosis in growth and weight gain,indicating that hybrid oysters are significantly better in stress resistance than their parents.