Atkinson David, Ciotti Benjamin J, Montagnes David J S
Population and Evolutionary Biology Research Group, School of Biological Sciences, The Biosciences Building, The University of Liverpool, Liverpool L69 7ZB, UK.
Proc Biol Sci. 2003 Dec 22;270(1533):2605-11. doi: 10.1098/rspb.2003.2538.
An inverse relationship between organism size and rearing temperature is widely observed in ectotherms ('the temperature-size rule', TSR). This has rarely been quantified for related taxa, and its applicability to protists also required testing. Here, we quantify the relationship between temperature and mean cell volume within the protists by a meta-analysis of published data covering marine, brackish water and freshwater autotrophs and heterotrophs. In each of 44 datasets, a linear relationship between temperature and size could not be rejected, and a negative trend was found in 32 cases (20 gave significant negative regressions, p < 0.05). By combining 65 datasets, we revealed, for each 1 degrees C increase, a cell-size reduction of 2.5% (95% CI of 1.7-3.3%) of the volume observed at 15 degrees C. The value did not differ across taxa (amoebae, ciliates, diatoms, dinoflagellates, flagellates), habitats, modes of nutrition or combinations of these. The data are consistent with two hypotheses that are capable of explaining the TSR in ectotherms generally: (i) resource, especially respiratory gas, limitation; and (ii) fitness gains from dividing earlier as population growth increases. Using the above relationship we show how changes in cell numbers with temperature can be estimated from changes in biomass and vice versa; ignoring this relationship would produce a systematic error.
在变温动物中广泛观察到生物体大小与饲养温度之间存在反比关系（“温度-大小规则”，TSR）。对于相关分类群，这种关系很少被量化，其对原生生物的适用性也需要进行测试。在这里，我们通过对已发表数据进行荟萃分析，量化了原生生物中温度与平均细胞体积之间的关系，这些数据涵盖了海洋、咸水和淡水自养生物及异养生物。在44个数据集中的每一个中，温度与大小之间的线性关系都无法被否定，并且在32个案例中发现了负相关趋势（20个给出了显著的负回归，p < 0.05）。通过合并65个数据集，我们发现，每升高1摄氏度，细胞大小会比在15摄氏度时观察到的体积减少2.5%（95%置信区间为1.7 - 3.3%）。该值在不同分类群（变形虫、纤毛虫、硅藻、甲藻、鞭毛虫）、栖息地、营养模式或这些因素的组合之间没有差异。这些数据与两个能够普遍解释变温动物中TSR的假设一致：（i）资源，尤其是呼吸气体，限制；以及（ii）随着种群增长增加，提前分裂带来的适应性增加。利用上述关系，我们展示了如何根据生物量的变化来估计细胞数量随温度的变化，反之亦然；忽略这种关系会产生系统误差。
