水环境中不同浓度K^+、Ca^(2+)对大鳞鲃幼鱼存活率、耗氧率和窒息点的影响

Effects of different K^+ and Ca^(2+) concentrations in water environment on the survival rate, oxygen consumption rate, and suffocation point of juvenile Barbus capito

通过单因子静态急性毒性试验和呼吸生理试验,研究了盐度10的水体中不同K+、Ca2+浓度对大鳞鲃(Barbus capito)幼鱼存活率、耗氧率和窒息点的影响。结果表明:在K+浓度3.78～435.30mg·L-1(对照组为117.55mg·L-1)和Ca2+浓度11.01～1535.90mg·L-1(对照组为116.59mg·L-1)水质条件下,大鳞鲃幼鱼存活率均为100%。96h高浓度K+的LC50为515.01mg·L-1,低浓度Ca2+的LC50为5.47mg·L-1。在耗氧率和窒息点试验中,低浓度K+组[(3.75±0.17)mg·L-1]大鳞鲃幼鱼在整个试验过程中的耗氧率和窒息点均未出现显著性变化(P>0.05);高浓度K+组[(451.67±10.23)mg·L-1]耗氧率在前48h未出现显著性变化(P>0.05),72和96h与对照组[(115.29±0.68)mg·L-1]相比,耗氧率显著提高(P<0.05);临界窒息点和绝对窒息点与对照组相比均显著升高(P<0.05)。Ca2+试验中,高Ca2+组[(1290.10±15.75)mg·L-1]和低Ca2+组[(8.87±0.34)mg·L-1]表现为相同趋势,即前24h时高浓度Ca2+组和低浓度Ca2+组耗氧率均比对照组[(117.57±1.68)mg·L-1]有显著升高(P<0.05),48h后,高浓度Ca2+组和低浓度Ca2+组耗氧率恢复到对照组水平并持续至96h试验结束。无论低浓度Ca2+组还是高浓度Ca2+组,大鳞鲃幼鱼的临界窒息点与绝对窒息点都显著升高(P<0.05)。综上所述,大鳞鲃幼鱼对水体中K+、Ca2+具有较强的耐受性,尤其是低浓度K+和高浓度Ca2+。

A single-factor static acute toxicity test was conducted to study the eitects ot dltterent concentrations K＋ and Ca2＋ in a water body with salinity 10 on the survival rate, oxygen consump- tion rate, and suffocation point of juvenile Barbus capito. At the K＋ concentration 3.78-435.30 rag· L-1 and Caz＋ concentration 11.01-1535.90 mg · L-l（with 117.55 mg · L-l of K＋ and 116.59 mg· L-1 of Caa＋ as the controls） , all the juveniles could survive. The 96 h LCs0 of high concentration K＋ and of low concentration Ca2＋ was 515.01 mg · L-1 and 5.47 mg·L-1 , respec- tively. At low concentration K＋ （ 3 . 75 ±0.17 mg· L-1 ） , no significant variations were observed in the oxygen consumption rate and suffocation point of juvenile Barbus capito （ P〉0.05 ） ; at high concentration K＋（451.67±10.23 mg · L-1 ）, the oxygen consumption rate at 48 h had no significant difference with the control （ P〉0.05 ）, but that at 72 h and 96 h increased significant-ly （P〈0.05）, and both the critical and the absolute suffocation points had a significant increase （P〈0.05）. At low concentration Ca2＋（8. 87＋0. 34 mg · L-1） and high concentration Ca2 （ 1290. 10±15.75 mg· L-1 ）, the oxygen consumption rate presented the same tendency, i. e. , increased significantly at 24 h （ P〈0.05 ）, declined at 48 h, and had no significant difference with the control （ P〉0.05 ） at 96 h. Whether at low or at high concentration Ca2＋both the criti- cal and the absolute suffocation points of the juveniles increased significantly （P 〈0.05 ）, as compared to the control. To sum up, the juvenile Barbus capito had stronger tolerance to the K＋ and Ca2＋ in water body, especially to the low concentration K＋ and high concentration Ca2＋.