不同仿刺参育种群体对热胁迫的生理响应OA

This study aims to elucidate the physiological mechanisms underlying heat tolerance,a key selective trait in the sea cucumber Apostichopusjaponicas,by examining dynamic changes in antioxidant,immune-related,and metabolic enzyme activities under varying heat shock temperatures,and by evaluating the thermal stability of the critical heat-tolerant enzyme malate dehydrogenase.Using a graded temperature elevation protocol for heat shock treatmentwith four geographical hybrid populations(WFD♀×RZ♂,WFD♀×YT♂,WFD♀×TS♂,WFD♀×WFD♂)and two early heat shock populations(blastocyst stage,big ear larvae stage)as materials,the enzymatic activities and thermal stability of superoxide dismutase(SOD),catalase(CAT),lactate dehydrogenase(LDH),pyruvate kinase(PK),and cytoplasmic malate dehydrogenase(cMDH)were systematically measured and analyzed in the body walls of juvenile sea cucumbers from different breeding populations.The results revealed that:(1)the WFD♀×RZ♂ population exhibited significantly higher SOD,CAT,PK,and cMDH activities compared to other hybrid combinations(P<0.05);(2)under heat stress conditions(34℃and 36℃),individuals heat-shocked at the late auricularia stage showed significantly greater SOD,CAT,LDH,and cMDH activities than those treated at the blastula stage(P<0.05);(3)starting from the 5-minute time point post-heat treatment,the residual cMDH activity remained significantly higher in the late auricularia group than in the blastula group across all subsequent time points;(4)among the hybrid populations,the cMDH thermal stability in the WFD ♀×YT ♂ and WFD ♀×RZ ♂ groups was markedly superior to that in the other two populations.In summary,these findings indicate that the WFD ♀×RZ ♂population and individuals exposed to heat shock at the late auricularia stage possess enhanced potential for heat tolerance.This study provides valuable theoretical insights and empirical data to support the screening of stress-resistant sea cucumber germplasm and the advancement of sustainable aquaculture practices.