Buxton Lucy, Takahashi Shunichi, Hill Ross, Ralph Peter J
Plant Functional Biology Climate Change Cluster, School of the Environment, University of Technology Sydney, Sydney, New South Wales 2007, AustraliaARC Centre of Excellence in Plant Energy Biology, Molecular Plant Physiology Group, Research School of Biological Sciences, The Australian National University, Canberra, Australian Capital Territory, AustraliaPlant Functional Biology Climate Change Cluster, School of the Environment, University of Technology Sydney, Sydney, New South Wales 2007, Australia.
J Phycol. 2012 Feb;48(1):117-26. doi: 10.1111/j.1529-8817.2011.01099.x. Epub 2011 Dec 20.
Exposure to elevated temperature is known to cause photosynthetic inhibition in the coral symbiont Symbiodinium sp. Through the use of the artificial electron acceptor, methyl viologen, this study identified how reduced photosynthetic capacity occurs as a result of inhibition up- and/or downstream of ferredoxin in Symbiodinium sp. in hospite and in culture. Heterogeneity between coral species and symbiont clades was identified in the thermal sensitivity of photosynthesis in the symbionts of the scleractinian corals Stylophora pistillata and Pocillopora damicornis, as well as among Symbiodinium cultures of clades A, B, and C. The in hospite symbionts of S. pistillata and the cultured clade C Symbiodinium both exhibited similar patterns in that their primary site of thermal inhibition occurred downstream of ferredoxin at 32°C. In contrast, the primary site of thermal inhibition occurred upstream of ferredoxin in clades A and B at 32°C, while at 34°C, all samples showed combined up- and downstream inhibition. Although clade C is common to both P. damicornis and S. pistillata, the manner of thermal inhibition was not consistent when observed in hospite. Results showed that there is heterogeneity in the primal site of thermal damage in Symbiodinium among coral species and symbiont clades.
已知暴露于高温会导致珊瑚共生体虫黄藻（Symbiodinium sp.）的光合作用受到抑制。通过使用人工电子受体甲基紫精，本研究确定了在虫黄藻体内和培养环境中，由于铁氧化还原蛋白上下游的抑制作用，光合作用能力下降是如何发生的。在造礁石珊瑚鹿角杯形珊瑚（Stylophora pistillata）和鹿角珊瑚（Pocillopora damicornis）的共生体中，以及在A、B和C类群的虫黄藻培养物中，均发现了珊瑚物种和共生体类群之间在光合作用热敏感性方面的异质性。鹿角杯形珊瑚的体内共生体和培养的C类群虫黄藻都表现出相似的模式，即在32°C时，它们的热抑制主要位点发生在铁氧化还原蛋白的下游。相比之下，在32°C时，A类群和B类群的热抑制主要位点发生在铁氧化还原蛋白的上游，而在34°C时，所有样本均表现出上下游联合抑制。尽管C类群在鹿角珊瑚和鹿角杯形珊瑚中都很常见，但在体内观察时，热抑制方式并不一致。结果表明，在珊瑚物种和共生体类群中，虫黄藻热损伤最初位点存在异质性。
