Hoadley Kenneth D, Pettay D Tye, Grottoli Andréa G, Cai Wei-Jun, Melman Todd F, Schoepf Verena, Hu Xinping, Li Qian, Xu Hui, Wang Yongchen, Matsui Yohei, Baumann Justin H, Warner Mark E
School of Marine Science and Policy, University of Delaware, Lewes, DE, United States.
School of Earth Sciences, The Ohio State University, Columbus, OH, United States.
Sci Rep. 2015 Dec 16;5:18371. doi: 10.1038/srep18371.
The physiological response to individual and combined stressors of elevated temperature and pCO2 were measured over a 24-day period in four Pacific corals and their respective symbionts (Acropora millepora/Symbiodinium C21a, Pocillopora damicornis/Symbiodinium C1c-d-t, Montipora monasteriata/Symbiodinium C15, and Turbinaria reniformis/Symbiodinium trenchii). Multivariate analyses indicated that elevated temperature played a greater role in altering physiological response, with the greatest degree of change occurring within M. monasteriata and T. reniformis. Algal cellular volume, protein, and lipid content all increased for M. monasteriata. Likewise, S. trenchii volume and protein content in T. reniformis also increased with temperature. Despite decreases in maximal photochemical efficiency, few changes in biochemical composition (i.e. lipids, proteins, and carbohydrates) or cellular volume occurred at high temperature in the two thermally sensitive symbionts C21a and C1c-d-t. Intracellular carbonic anhydrase transcript abundance increased with temperature in A. millepora but not in P. damicornis, possibly reflecting differences in host mitigated carbon supply during thermal stress. Importantly, our results show that the host and symbiont response to climate change differs considerably across species and that greater physiological plasticity in response to elevated temperature may be an important strategy distinguishing thermally tolerant vs. thermally sensitive species.
在24天的时间里，对四种太平洋珊瑚及其各自的共生体（多孔鹿角珊瑚/共生藻C21a、鹿角杯形珊瑚/共生藻C1c-d-t、团块微孔珊瑚/共生藻C15以及肾形涡轮珊瑚/共生藻trenchii）对高温和pCO₂单一及联合应激源的生理反应进行了测量。多变量分析表明，高温在改变生理反应方面发挥了更大作用，变化程度最大的发生在团块微孔珊瑚和肾形涡轮珊瑚中。团块微孔珊瑚的藻类细胞体积、蛋白质和脂质含量均增加。同样，肾形涡轮珊瑚中的共生藻trenchii体积和蛋白质含量也随温度升高而增加。尽管最大光化学效率有所下降，但在两种对热敏感的共生藻C21a和C1c-d-t中，高温下生化成分（即脂质、蛋白质和碳水化合物）或细胞体积几乎没有变化。多孔鹿角珊瑚中细胞内碳酸酐酶转录本丰度随温度升高而增加，但鹿角杯形珊瑚中则没有，这可能反映了热应激期间宿主缓解碳供应的差异。重要的是，我们的结果表明，宿主和共生体对气候变化的反应在不同物种间存在很大差异，并且对温度升高具有更大的生理可塑性可能是区分耐热物种与热敏感物种的重要策略。
