Jeyasingh Punidan D
Graduate Program in Ecology and Evolutionary Biology, Biological Station and Department of Zoology, University of Oklahoma, Norman, OK 73019, USA.
Ecol Lett. 2007 Apr;10(4):282-9. doi: 10.1111/j.1461-0248.2007.01023.x.
Metabolism involves multiple elements. While we know much about the allometry in metabolic response of organisms to energy (carbon, C) availability, little is known about how different-sized organisms respond to the relative availability of elements. I experimentally manipulated availability of phosphorus (P) relative to C, to test whether dietary C : P affects metabolism in four species of Daphnia, spanning an order of magnitude in body mass. Results indicated that the slope of the relationship between individual respiration and body mass was M(0.83) under a balanced diet (C : P c. 150), and M(0.67) under an imbalanced diet (C : P c. 800). Increased respiration under dietary imbalance was not due to increased ingestion. The change in the scaling exponent was due to the greater respiratory response of smaller species to altered diets. Diet-induced metabolic plasticity contributes to variation in metabolic allometry, at least at such small scales of body size.
新陈代谢涉及多个要素。虽然我们对生物体代谢对能量（碳，C）可利用性的异速生长了解很多，但对于不同大小的生物体如何响应元素的相对可利用性却知之甚少。我通过实验操纵了磷（P）相对于C的可利用性，以测试饮食中C：P是否会影响四种水蚤的新陈代谢，这四种水蚤的体重相差一个数量级。结果表明，在均衡饮食（C：P约为150）下，个体呼吸与体重之间关系的斜率为M（0.83），而在不均衡饮食（C：P约为800）下为M（0.67）。饮食不均衡时呼吸增加并非由于摄食增加。标度指数的变化是由于较小物种对饮食变化的呼吸反应更大。饮食诱导的代谢可塑性至少在如此小的体型尺度上导致了代谢异速生长的变化。
