两种形态变异类型日本囊对虾稚虾高温耐受性的比较

The thermotolerance of the two morphologically similar varieties of juvenile kuruma shrimp( Marsupenaeus japonicus)

高温耐受值（CTMax）为评估日本囊对虾稚虾高温耐受性的重要指标，本实验探讨了不同暂养温度（24、28和32℃）和升温速率[（1±0．2）℃／h和（1±0．2）℃／min]对CTMax值的影响，同时利用CTMax和环境响应系数ARR比较了两种形态变异类型日本囊对虾稚虾的高温耐受性差异，并从二者的地理分布、耗氧率、窒息点和温度系数Q10生理代谢指标对其高温耐受机理进行了分析。实验结果如下：（1）不同的暂养温度和升温速率对两种形态变异类型日本囊对虾稚虾的CTMax值均有显著影响（P〈0．05）；（2）在相同升温速率下，32℃组形态变异类型Ⅱ稚虾的CTMax值高于形态变异类型I（P〈0．05），各实验温度范围内形态变异类型Ⅱ稚虾的ARR值都显著大于形态变异类型I（P〈0．05）；（3）各温度组中形态变异类型Ⅰ稚虾的耗氧率和窒息点均高于形态变异类型Ⅱ（P〈0．05）；（4）形态变异类型Ⅰ稚虾在24～28℃的Q。值小于28～32℃的Q10值，而形态变异类型Ⅱ稚虾则与此相反，二者的适温范围不同。结果表明，不同温度对日本囊对虾稚虾的CTMax值、耗氧率和窒息点均有影响，主要分布于南海水域的形态变异类型Ⅱ稚虾的高温耐受性强于主要分布于东海和南海北部的形态变异类型Ⅰ稚虾。

For the reason that the critical thermal maximum （CTMax）is an excellent index for evaluating the thermal tolerance, we assessed the impact of different acclimation temperatures （24,28,32 ℃ ） and heating rates [ （ 1 ± 0. 2 ） ℃ /h and （ 1 ±0. 2 ） ℃ /min ] on the CTMax values firstly. And then we compared the difference of the thermotolerance between the two morphologically similar varieties of juvenile kuruma shrimp Marsupenaeus japonicus （Bate, 1888 ）by the CTMax values and the acclimation response ratio （ARR） values, and at the same time, the different distribution, the physiological traits of the oxygen consumption rate, suffocation point and temperature coefficient（Ql0） of the two varieties were analysed to explore their thermal tolerance mechanism. The results are as follows ： （ 1 ） Significant effect was found on the CTMax values of the shrimps by different heating rates and acclimation temperatures （ P 〈 0.05 ）. （2） At the acclimation temperature of 32 ℃ , the CTMax value of variety Ⅱ was greater than that of variety Ⅰ （P 〈 0.05） and the ARR values of variety Ⅱ were also greater than variety Ⅰ at all temperature intervals. （3） When exposed to the same acclimation temperature, the oxygen consumption rate and suffocation point of the variety Ⅰ were greater than those of variety Ⅱ （P 〈 0.05）. （4） The temperature coefficient（Q10） value of variety I at the temperature interval of 28 - 32 ℃ was greater than that of 24 - 28 ℃, while the result of variety Ⅱ was quite the contrary, and there was a difference between the optimum temperature of the two varieties. The results obtained in this work showed that the CTMax values, oxygen consumption rate and suffocation point of the juvenile kuruma shrimp were influenced by different acclimation temperatures and the thermotolerance of variety Ⅱ which is mainly distributed in the South China Sea was stronger than that of variety I which is distributed in the East China Sea and the northern part of the South China Sea.