高盐胁迫对缢蛏幼贝存活和三种酶活性的影响

Effects of high salt stress on survival and enzyme activities of Sinonovacula constricta juvenile

为探讨高盐胁迫对壳长约2 cm缢蛏(Sinonovacula constricta)幼贝存活和酶活性的影响,本研究设置盐度分别为20‰(S_(20))、25‰(S_(25))、30‰(S_(30))、35‰(S_(35))、40‰(S_(40))和45‰(S_(45))6个组别胁迫缢蛏,测定各组幼贝死亡率,并计算不同胁迫时间的半致死盐度(LC_(50));同时研究了S_(20)、S_(30)和S_(40)组幼贝软体部Na^(+)-K^(+)-ATP酶(NKA)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)三种酶在不同胁迫时间的活性变化特征。结果表明,实验处理120 h后,各组死亡率分别为0、(2.17±0.85)%、(9.50±0.82)%、(30.67±3.70)%、(73.50±7.08)%和(94.67±3.06)%,168 h时S_(45)组的缢蛏幼贝全部死亡;直线内插法计算得到的72、96、120、144、168 h的高盐LC_(50)分别为46.03‰、39.85‰、35.77‰、34.57‰、33.69‰,概率单位法得到的高盐LC_(50)分别为44.31‰、40.74‰、36.96‰、35.67‰、34.47‰。随着盐度升高和处理时间延长,NKA、AKP与ACP活性总体上呈现先上升再下降后稳定的趋势,三种酶活性变化趋势相似,但效应时间不同,盐度高于30‰会给幼贝机体造成较大伤害,能降低机体渗透压调节和免疫防御机能,甚至导致死亡。研究结果为高盐条件下开展缢蛏科学养殖提供了参考数据。

To investigate the effects of high salt stress on the survival and enzyme activities of Sinonovacula constricta juvenile with a shell length of~2 cm,the individuals were randomly divided into six groups with different salinities of 20‰(S_(20)),25‰(S_(25)),30‰(S_(30)),35‰(S_(35)),40‰(S_(40))and 45‰(S_(45)).The mortalities of S.constricta juvenile in each group were calculated,and the half lethal salinity(LC_(50))at different stress times was analyzed by two methods.Furthermore,the activities of Na^(+)-K^(+)-ATPase(NKA),acid phosphatase(ACP),and alkaline phos-phatase(AKP)of the individuals from groups S_(20),S_(30),and S_(40)were analyzed,respectively.The results showed that the mortality rates of groups S_(20),S_(25),S_(30),S_(35),S_(40),and S_(45)at 120 h were 0,(2.17±0.85)%,(9.50±0.82)%,(30.67±3.70)%,(73.50±7.08)%,and(94.67±3.06)%,respectively.All the individuals of group S_(45)died at 168 h.The LC_(50)of high salinity analyzed at 72,96,120,144,and 168 h were 46.03‰、39.85‰、35.77‰、34.57‰and 33.69‰,respectively,via the linear regression method,and 44.31‰,40.74‰,36.96‰,35.67‰and 34.47‰,respectively,via the probit analysis method.As the salinity increased and the treatment lasted longer,NKA,AKP,and ACP activities first increased,further decreasing and stabilizing.The three enzymes showed similar change trends with different effect times.Salinity above 30‰might cause great damage to the body by reducing the osmotic pressure regulation and immune defense function.This study provides useful data for the future culture of S.constricta.