Impact of bleaching stress on the function of the oxygen evolving complex of zooxanthellae from scleractinian corals
Impact of bleaching stress on the function of the oxygen evolving complex of zooxanthellae from scleractinian corals
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DOI：
10.1111/j.1529-8817.2008.00468.x
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发表时间：
2008-04-01
影响因子：
2.9
通讯作者：
Ralph, Peter J.
中科院分区：
文献类型：
--
作者：
Hill, Ross;Ralph, Peter J.
全球气候变化导致海洋温度上升，并引发世界各地珊瑚礁的大规模珊瑚漂白事件。据信，共生甲藻的驱逐是由于这些共生体的光合装置受到破坏而发生的，尽管最初撞击的具体地点尚未最终确定。在这里，放氧复合物（OEC）漂白应力的敏感性进行了研究，以及它的季节之间的自然变化。人工电子供体，二苯基卡巴肼（DPC），加入到培养，新鲜分离和驱逐（漂白处理）虫黄藻悬浮液。叶绿素a荧光和氧产生的测量结果表明，加入DPC后，没有恢复减少的光化学效率发生在控制或漂白条件下。这一结果是一致的12小时和5天漂白处理Pocilloporadamicornis，表明OEC是不是主要的损害部位，和虫黄嘌呤驱逐从主机是一个非选择性的过程，相对于OEC的功能。测量快速感应曲线（FIC）的进一步实验表明，在夏季和冬季，OEC功能丧失时的温度发生在海面温度以上7摄氏度至14摄氏度之间。FIC和氧的产生测量的P. damicornis在暴露于漂白应力表明，耐热性的OEC的温度以上的漂白处理超过4小时的时间内增加。这一发现表明，OEC有能力在季节之间适应，并在远高于漂白阈值的温度下保持功能。
Global climate change is leading to the rise of ocean temperatures and is triggering mass coral bleaching events on reefs around the world. The expulsion of the symbiotic dinoflagellate algae is believed to occur as a result of damage to the photosynthetic apparatus of these symbionts, although the specific site of initial impact is yet to be conclusively resolved. Here, the sensitivity of the oxygen evolving complex (OEC) to bleaching stress was studied as well as its natural variation between seasons. The artificial electron donor, diphenyl carbazide (DPC), was added to cultured, freshly isolated and expelled (bleaching treatments only) zooxanthellae suspensions. Chl a fluorescence and oxygen production measurements showed that upon addition of DPC, no restoration of diminished photochemical efficiency occurred under control or bleaching conditions. This result was consistent between 12 h and 5 d bleaching treatments on Pocilloporadamicornis, indicating that the OEC is not the primary site of damage, and that zooxanthellae expulsion from the host is a nonselective process with respect to the functioning of the OEC. Further experiments measuring fast induction curves (FICs) revealed that in both summer and winter, the temperature when OEC function was lost occurred between 7 degrees C and 14 degrees C above the sea surface temperature. FIC and oxygen production measurements of P. damicornis during exposure to bleaching stress demonstrated that the thermotolerance of the OEC increased above the temperature of the bleaching treatment over a 4 h period. This finding indicates that the OEC has the capacity to acclimate between seasons and remains functional at temperatures well above bleaching thresholds.