盐度胁迫对魁蚶稚贝血淋巴渗透压及鳃Na^+/K^+-ATP酶活力的影响

Effect of salinity stress on hemolymph osmolality and gill Na^+/ K^+-ATPase activity of juvenile ark shell( Anadara broughtonii)

文章研究了盐度胁迫下魁蚶(Anadara broughtonii)稚贝(壳长25~35 mm)血淋巴渗透压和鳃Na+/K+-ATP酶活力的变化。结果显示,突变胁迫下,盐度20、25、35、40组的稚贝血淋巴渗透压均在48 h内显著降低或波动升高后趋于稳定,盐度15组则需96 h完成波动调整。以日变幅5渐变至高盐40过程中,稚贝血淋巴渗透压在48 h内趋于稳定;低盐15组仅需72 h完成渗透压调节,调整时间显著小于突变组。盐度突降胁迫下,各处理组稚贝鳃Na+/K+-ATP酶活力12 h后显著升高,24 h分别达到最大值,随后快速回落并稳定在高于对照组水平;盐度骤升胁迫下,鳃ATP酶活力波动降低,在12~24 h达到最小值后稳定在低于对照组水平。低盐(15)和高盐(40)渐变组的鳃ATP酶活力变幅均小于突变组。盐度胁迫下鳃Na+/K+-ATP酶活力的响应方式不同,即低盐胁迫时活力增强,高盐胁迫时活力降低。采用盐度渐变的驯化处理更有利于魁蚶稚贝应对盐度胁迫。

The study investigated the variations of hemolymph osmolality and gill Na＋/ K＋-ATPase activity in juvenile ark shell（ Anadara broughtonii）（ shell length 25 - 35 mm） under different salinity stresses. The results show that the hemolymph osmolality under abrupt stress at salinities of 20,25,35 and 40 decreased significantly or fluctuated ascendingly then became stable in 48 h. At salinity of 15,the juveniles needed 96 h to complete the adjustment. At a changing salinity rate of 5·d- 1,the hemolymph osmolality at salinity of 40 tended to be stable in 48 h but in 72 h at salinity of 15,which was faster than at salinity of 15. After an abrupt decrease in salinity,the Na＋/ K＋-ATPase activity of gills increased significantly in 12 h and each treatment reached its peak in 24 h. Then the activity quickly dropped and returned to a steady state higher than the control,and with an abrupt increase of salinity,it fluctuated descendingly and reached the bottom in 12 - 24 h lower than the control. The activity changed much less at salinity of 15 and 40 than at sudden-change salinity. In conclusion,the response patterns of Na＋/ K＋-ATPase activity of gills under different salinity stresses were different,i. e.,the activity increased under low salinity stress but decreased under high salinity stress. It is suggested that gradual salinity change would be helpful for A. broughtonii to adapt to salinity stress.