Contrasting physiological plasticity in response to environmental stress within different cnidarians and their respective symbionts
Contrasting physiological plasticity in response to environmental stress within different cnidarians and their respective symbionts
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DOI：
10.1007/s00338-016-1404-5
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发表时间：
2016-06-01
期刊：
影响因子：
3.5
通讯作者：
Warner, Mark E.
中科院分区：
文献类型：
--
作者：
Hoadley, Kenneth D.;Pettay, Daniel. T.;Warner, Mark E.
考虑到对珊瑚白化和海洋酸化的担忧，人们对描述珊瑚礁上常见的多种宿主-藻类共生体组合的生理差异产生了新的兴趣。使用升高的温度和二氧化碳来比较石珊瑚门珊瑚 Montipora hirsuta (Symbiodinium C15) 和 Pocillopora damicornis (Symbiodinium D1) 以及珊瑚形珊瑚 (一种与石珊瑚密切相关的非钙化珊瑚虫) Discosoma nummiforme (Symbiodinium C3) 内的生理反应。与 CO2 相比，一些生理指标更容易受到温度的影响，包括光化学、藻类数量和细胞叶绿素 a。共生体数量、叶绿素和体积的显着差异导致了这些动物叶绿素吸收的独特模式。相反，在升高的温度下，碳固定要么没有改变，要么增加。此外，光合固定碳转移到每个宿主的速率没有变化，并且在珊瑚形体中转移到宿主的碳百分比有所增加。比较所有数据揭示了光合速率和共生体密度之间存在显着的负相关性，这证实了先前关于这些共生体中碳限制的假设。对这些生物以及寄生共生藻的海葵 Exaiptasia pallida 中的共生体标准化光合速率相对于共生体标准化碳易位速率 (P:T) 的比率进行了比较，结果显示 P:T 接近统一 (D. nummiforme)，范围为 2.0-4.5，其中海葵中的碳易位最低。这些生物体热反应的主要差异提供了一系列适应潜力和生理可塑性的进一步证据，这凸显了继续研究更大的宿主类群中的这些共生关系的必要性。
Given concerns surrounding coral bleaching and ocean acidification, there is renewed interest in characterizing the physiological differences across the multiple host-algal symbiont combinations commonly found on coral reefs. Elevated temperature and CO2 were used to compare physiological responses within the scleractinian corals Montipora hirsuta (Symbiodinium C15) and Pocillopora damicornis (Symbiodinium D1), as well as the corallimorph (a non-calcifying anthozoan closely related to scleractinians) Discosoma nummiforme (Symbiodinium C3). Several physiological proxies were affected more by temperature than CO2, including photochemistry, algal number and cellular chlorophyll a. Marked differences in symbiont number, chlorophyll and volume contributed to distinctive patterns of chlorophyll absorption among these animals. In contrast, carbon fixation either did not change or increased under elevated temperature. Also, the rate of photosynthetically fixed carbon translocated to each host did not change, and the percent of carbon translocated to the host increased in the corallimorph. Comparing all data revealed a significant negative correlation between photosynthetic rate and symbiont density that corroborates previous hypotheses about carbon limitation in these symbioses. The ratio of symbiont-normalized photosynthetic rate relative to the rate of symbiont-normalized carbon translocation (P:T) was compared in these organisms as well as the anemone, Exaiptasia pallida hosting Symbiodinium minutum, and revealed a P:T close to unity (D. nummiforme) to a range of 2.0-4.5, with the lowest carbon translocation in the sea anemone. Major differences in the thermal responses across these organisms provide further evidence of a range of acclimation potential and physiological plasticity that highlights the need for continued study of these symbioses across a larger group of host taxa.