PHOTOBIOLOGY OF THE SYMBIOTIC SEA-ANEMONE, ANTHOPLEURA-ELEGANTISSIMA - DEFENSES AGAINST PHOTODYNAMIC EFFECTS, AND SEASONAL PHOTOACCLIMATIZATION
PHOTOBIOLOGY OF THE SYMBIOTIC SEA-ANEMONE, ANTHOPLEURA-ELEGANTISSIMA - DEFENSES AGAINST PHOTODYNAMIC EFFECTS, AND SEASONAL PHOTOACCLIMATIZATION
复制标题
DOI：
10.2307/1541419
复制
发表时间：
1984-01-01
影响因子：
1.6
通讯作者：
SHICK, JM
中科院分区：
文献类型：
--
作者：
DYKENS, JA;SHICK, JM
海葵 A.优雅含有光合共生体（虫黄藻），对暴露于阳光和光合作用产生的高压氧气的综合环境压力做出生化和行为反应。超氧化物歧化酶 (SOD) 和过氧化氢酶的活性与叶绿素的分布平行，它们协同防御 O2 毒性。 A. beautifulissima 显示出精细控制的收缩行为，可以遮蔽虫黄藻并减少 O2 的产生，但会使身体柱组织直接暴露在阳光下。身体柱含有不成比例的高 SOD 和过氧化氢酶活性，可防御光动力损伤。 SOD 的这种额外作用在适应遮荫的无性共生海葵中得到了证明，其中在阳光照射 7 天后，SOD 和过氧化氢酶活性分别增加 590% 和 100%。为了应对氧气水平升高和阳光照射，雅致海藻将砾石和其他碎片附着在其身体表面，作为防晒霜，有效减少暴露在明亮阳光下虫黄藻的排出。海葵叶绿素含量随季节波动，与平均太阳辐射呈反比变化。这些季节变化并不是由于藻类细胞数量的相应变化，而是由于相当均匀的虫黄藻的叶绿素含量和叶绿素 a:c2 比例的变化。
The sea anemone A. elegantissima, which contains photosynthetic symbionts (zooxanthellae), responds both biochemically and behaviorally to the combined environmental stresses of exposure to sunlight and photosynthetically generated hyperbaric O2. Activities of the enzymes superoxide dismutase (SOD) and catalase, which act in concert as defenses against O2 toxicity, parallel the distribution of chlorophyll. A. elegantissima shows a finely controlled contraction behavior which shades the zooxanthellae and reduces O2 production, but which leaves the body column tissues directly exposed to sunlight. The body column contains disproportionately high SOD and catalase activities as defenses against photodynamic damage. This additional role of SOD is demonstrated by shade-adapted aposymbiotic anemones in which SOD and catalase activities increase by 590% and 100%, respectively, following a 7 day exposure to sunlight. In response to elevated levels of O2 and sunlight exposure, A. elegantissima attaches gravel and other debris to its body surface which serves as a sunscreen that effectively reduces zooxanthella expulsion during exposure to bright sunlight. Anemone chlorophyll content fluctuates on a seasonal basis, varying inversely with mean solar radiation. These seasonal changes are not due to corresponding changes in the number of algal cells, but rather to changes in the chlorophyll content and chlorophyll a:c2 ratio of a fairly uniform standing crop of zooxanthellae.