Jimenez Ana Gabriela, Jayawardene Sarah, Alves Shaina, Dallmer Jeremiah, Dowd W Wesley
Department of Biology, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
Department of Chemistry and Biochemistry, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
Proc Biol Sci. 2015 Dec 7;282(1820):20152273. doi: 10.1098/rspb.2015.2273.
The contributions of temporal and spatial environmental variation to physiological variation remain poorly resolved. Rocky intertidal zone populations are subjected to thermal variation over the tidal cycle, superimposed with micro-scale variation in individuals' body temperatures. Using the sea mussel (Mytilus californianus), we assessed the consequences of this micro-scale environmental variation for physiological variation among individuals, first by examining the latter in field-acclimatized animals, second by abolishing micro-scale environmental variation via common garden acclimation, and third by restoring this variation using a reciprocal outplant approach. Common garden acclimation reduced the magnitude of variation in tissue-level antioxidant capacities by approximately 30% among mussels from a wave-protected (warm) site, but it had no effect on antioxidant variation among mussels from a wave-exposed (cool) site. The field-acclimatized level of antioxidant variation was restored only when protected-site mussels were outplanted to a high, thermally stressful site. Variation in organismal oxygen consumption rates reflected antioxidant patterns, decreasing dramatically among protected-site mussels after common gardening. These results suggest a highly plastic relationship between individuals' genotypes and their physiological phenotypes that depends on recent environmental experience. Corresponding context-dependent changes in the physiological mean-variance relationships within populations complicate prediction of responses to shifts in environmental variability that are anticipated with global change.
时间和空间环境变化对生理变化的贡献仍未得到很好的解决。潮间带岩石区种群在潮汐周期中会经历温度变化，个体体温还存在微观尺度的变化。我们以加州贻贝（Mytilus californianus）为研究对象，评估了这种微观尺度环境变化对个体间生理变化的影响，首先通过研究野外适应环境的动物的生理变化，其次通过共同园驯化消除微观尺度的环境变化，最后通过互置移植方法恢复这种变化。共同园驯化使来自受波浪保护（温暖）地点的贻贝组织水平抗氧化能力的变化幅度降低了约30%，但对来自受波浪冲击（凉爽）地点的贻贝的抗氧化变化没有影响。只有当受保护地点的贻贝被移植到高温、热应激大的地点时，抗氧化变化的野外适应水平才得以恢复。生物耗氧率的变化反映了抗氧化模式，在共同园驯化后，受保护地点的贻贝的耗氧率大幅下降。这些结果表明，个体基因型与其生理表型之间存在高度可塑性的关系，这种关系取决于近期的环境经历。种群内生理均值 - 方差关系中相应的上下文依赖变化，使得预测对全球变化预期的环境变异性变化的反应变得复杂。
