Ultsch G R, Duke J T
Department of Biology, The University of Alabama, 35487, Tuscaloosa, AL, USA.
Oecologia. 1990 Jun;83(2):250-8. doi: 10.1007/BF00317760.
The standard metabolic rate (SMR) and critical O(2) tension (P(c)) of water-breathing mudpuppies and hellbenders were determined at 20° C using open-system respirometry. Both species are metabolic O(2) regulators, although the P(c) of hellbenders (90 mmHg) is much higher than that of mudpuppies (40 mmHg). The SMR of the two species in water saturated with air was similar (19.5 and 20.0 μl O(2)/g·h for Cryptobranchus and Necturus, respectively) and not different from that of salamanders in general. Both species were able to survive for at least 5-11 days in severely hypoxic water (9-10 mmHg) by breathing air, indicating that the lungs are functional accessory respiratory structures.We conclude that hellbenders are restricted to relatively cool and flowing waters because of their limited gas exchange capabilities, particularly with regard to their limited aerobic scope for activity and slow recovery from exercise. Necturus maculosus is much more tolerant of hypoxia, but it is not known if they can inhabit areas were hypoxia is combined with hypercarbia.
在20°C下，使用开放系统呼吸测定法测定了水栖泥螈和隐鳃鲵的标准代谢率（SMR）和临界氧张力（P(c)）。这两个物种都是代谢性氧调节者，尽管隐鳃鲵的P(c)（90 mmHg）远高于泥螈的P(c)（40 mmHg）。在空气饱和的水中，这两个物种的SMR相似（隐鳃鲵和泥螈分别为19.5和20.0 μl O(2)/g·h），与一般蝾螈的SMR没有差异。通过呼吸空气，这两个物种在严重缺氧的水（9 - 10 mmHg）中都能存活至少5 - 11天，这表明肺是功能性的辅助呼吸结构。我们得出结论，由于隐鳃鲵的气体交换能力有限，特别是其有限的有氧活动范围和运动后恢复缓慢，它们被限制在相对凉爽且流动的水域。黄斑泥螈对缺氧的耐受性要强得多，但尚不清楚它们是否能够栖息在缺氧与高碳酸血症并存的区域。
