强壮箭虫对温度、盐度的耐受性研究

PRELIMINARY STUDIES ON THE TOLERANCE TO TEMPERATURE AND SALINITY IN SAGITTA CRASSA

研究强壮箭虫对突变温度、突变盐度和渐变温度、渐变盐度的耐受性。结果表明:水温由15℃突变到1℃时,存活率为75%;水温由15℃突变为30℃时,存活率仅为5%。求得24h急性半致死温度上限为27.2℃。水温从20℃逐渐上升至25、30、35℃,存活率分别为85%、10%、0%;水温从20℃逐渐下降至15、10、5℃,其存活率分别为100%、95%和80%。盐度从31突变为20、40,箭虫的存活率均为100%,随着盐度突变幅度的增大,强壮箭虫的存活率呈降低趋势。求得24h急性半致死盐度上限为45,24h急性半致死盐度下限为13.3。盐度逐渐从31上升到46、52,其存活率由90%下降到0%;盐度逐渐从31降到13、6,其存活率由95%下降到0%。求得间隔12h半致死渐变盐度上限为48.7,半致死渐变盐度下限为9.3。根据实验结果,强壮箭虫应属喜冷广温种和近岸广盐种。

The tolerance to quickly - changed temperature and salinity, and gradually - changed temperature and salinity in Sagitta crassa were studied. The survival rate is 75% when the temperature changes from 15℃ to 1℃ ,but the survival rate is only 5% when the temperature changes from 15℃ to 30℃. The LTD（24）of sudden upper limit temperature is 27.2℃. When the temperature gradually changes from 20℃ to 25℃ ,30℃ and 35℃ ,the survival rate is 85% ,10% and 0% respectively. When the temperature gradually changes from 20℃ to 15℃ ,10℃ and 5℃ ,the survival rate is 100% ,95% 、80% respectively. When the salinity suddenly changes from 31 to 20 and 40,the survival rate is 100%. With the increase of salinity changing range, the survival rate of Sagitta crassa decreases ; The LTD（24） of sudden upper limit salinity is 45,and the lower limit is 13.3. The survival rate changes from 90% to 0 % ,when the Salinity changes from 46 to 52. Also,the survival rate changes from 95% to 0 % when the salinity changes from 13 to 6. The LTD（24）of gradual upper limit salinity is 48.7 and the LTD（24）of gradual lower limit salinity is 9.3. The results suggest that Sagitta crassa may be a eurythermal,psychrophilic species and euryhaline near coastal regions.