温度驯化对尖头鳉热耐受特征的影响

  • 摘要: 为了研究不同驯化温度对尖头鰂(Rhynchocypris oxycephalus)热耐受特征的影响, 本研究设置4组水温(14℃、19℃、24℃和29℃), 对尖头鰂驯化两周, 采用临界温度法观察尖头鰂的耐受温度。结果显示: 尖头鰂的热耐受性受到温度驯化的影响, 表现为高温驯化可以升高最大临界温度(CTmax), 4个驯化组的平均CTmax分别为32.29℃、33.23℃、33.40℃和35.71℃; 低温驯化可以降低最小临界温度(CTmin), 平均CTmin分别为0.00、0.10℃、2.10℃和5.27℃; 在适中的温度(19℃)驯化条件下具有最高的温度耐受范围(33.13℃)。在高温条件下的温度驯化具有较高的驯化反应率, 最大值出现在24—29℃内(0.46); 低温驯化反应率最大值出现在29—24℃内, 为0.63。尖头鰂在本研究的驯化区间(14—29℃)内的热耐受区域面积为478.98℃2, 与温水性鱼类的温度耐受性相当, 说明尖头鰂具有较强的温度适应能力。

     

    Abstract: Temperature is one of the most important environmental factors that impact the physiological activities of fishes. Fishes exhibit thermal tolerance, which are influenced by temperature acclimation. Global climate change is one potential factor affect the survival and growth of fish species. Therefore, investigation of thermal tolerance of various fish species is of great importance. Rhynchocypris oxycephalus is a typical cold-water fish that might be influenced by the future global warming. The current study investigated thermal tolerance of R. oxycephalus using critical thermal methodology by acclimating the fish to 14, 19, 24 and 29℃ temperature for two weeks. The results showed that thermal tolerance of R. oxycephalus regulated by temperature acclimation, and that the critical thermal maxima (CTmax) increased with the increase of temperature acclimation, and that the average CTmax were 32.29, 33.23, 33.40 and 35.71℃. The critical thermal minima (CTmin) decreased with the decrease of temperature acclimation, and the average CTmin were 0.00, 0.10, 2.10 and 5.27℃. At the moderate acclimation temperature (19℃), R. oxycephalus has the widest thermal tolerance up to 33.13℃. The higher acclimation temperatures produced higher acclimation response ratio (ARR). The maximum ARR (0.46) of high temperatures occurred in the range of 24—29℃, while the maximum ARR of low temperatures, (0.63) occurred in 29—24℃. A thermal tolerance polygon in the range of 14 to 29℃ showed an area of 478.98℃2, which was similar with eurythermal fishes. These results indicated that R. oxycephalus has strong ability for thermal adaption.

     

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