不同盐度对三角帆蚌钩介幼虫、稚贝生理活动和存活的影响

Effects of Different Salinity upon Physiological Activity and Survival of Glochidia and Juvenile of Hyriopsis cumingii

对三角帆蚌钩介幼虫、不同日龄稚贝在不同盐度条件下的生理活动和存活率进行了观察和比较。以淡水组作为对照组,试验结果显示:三角帆蚌钩介幼虫在淡水组48 h存活率达90%,而盐度2条件下,2 h内即全部死亡;同龄的稚贝存活率随生理盐水浓度、实验时间的增加而逐渐降低,生理活动明显受到盐度的影响,表现为心跳频率降低,肠道蠕动减弱,斧足运动减少;随作用时间的增加,稚贝表现为心跳停止、双壳张开死亡;大日龄稚贝在同盐度下的存活率显著高于低日龄稚贝,7日龄稚贝在48 h内所有盐度组全部死亡,45日龄稚贝仅在盐度为2试验液中有90%存活,但生理活动明显低于正常淡水组,表现为心跳微弱,无肠道斧足运动。因此,认为三角帆蚌钩介幼虫对盐度较敏感,其耐受力低于稚贝,而三角帆蚌稚贝的适宜盐度要低于2。

We observed the variation of physiological activity of glochidia and juvenile of Hyriopsis cumingii and compared the survival rate in different salinity.The variation of physiolgical activity in the freshwater was set as control.The results showed that 90% of glochidia survived after 48 h test in the freshwater,while there was no individual survived after 2 h even in normal saline with salinity 2.The higher the salinity was and the longer the response time was,the lower the survival rate of juvenile was.Salinity had significant effect on the physilogical activity of juvenile,including the decline of heartbeat,intestine and foot activity.With the test time increasing,the juvenile was going to die with the shell opening.The survival rate of juvenile with the larger day-old was higher than the smaller one.Acturally,all of 7 day-old juvenile died in salinity 2 to 9 solution after 48 h,while there were 90% of 45 day-old juvenile remianed survival in salinity 2 solution,with more faint heartbeat,intestine and foot activity comparing with the control group.Ultimately the glochidia were more sensitive to salinity than the juvenile and the suitable salinity range was set below 2.