Effects of desiccation on the excitation energy distribution from phycoerythrin to the two photosystems in the red alga Porphyra perforata
Effects of desiccation on the excitation energy distribution from phycoerythrin to the two photosystems in the red alga Porphyra perforata
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DOI：
10.1111/j.1399-3054.1982.tb04899.x
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发表时间：
1982-09
影响因子：
6.4
通讯作者：
G. Öquist;D. C. Fork
中科院分区：
文献类型：
--
作者：
G. Öquist;D. C. Fork
在低温（77°K）条件下，记录了多孔紫菜（Porphyra perforata）湿菌体和干菌体的荧光发射和激发光谱。在77°K下记录了光系统II陷阱关闭过程中光系统I（F730）和光系统II（F695）的荧光发射动力学。干燥诱导整个发射光谱的荧光产率降低，但减少是最明显的光系统II荧光带，F688和F695。结果表明，藻红蛋白致敏发射光谱的变化是由于1）光系统I天线的荧光产率降低，2）光系统II的荧光更强烈地降低，这是由对光系统I的激发溢出（kT（III））增加和光系统I的吸收截面α增加介导的。我们推测kT（III）和α的增加是一种机制的一部分，通过这种机制，耐干燥、高光照的紫菜可以避免光系统II的光动力损伤，当光合作用在低潮期间由于干燥而受到抑制时。
Low temperature (77°K) fluorescence emission and excitation spectra were recorded for wet and desiccated thalli of Porphyra perforata. The photosystem I (F730) and photosystem II (F695) fluorescence emission kinetics during photosystem II trap closure were also recorded at 77°K. Desiccation induced a lowering of the fluorescence yield over the whole emission spectrum but the decrease was most pronounced for the photosystem II fluorescence bands, F688 and F695. It was shown that the desiccation-induced changes of the phycoerythrin sensitized emission spectrum were due to 1) a decrease in the fluorescence yield of the photosystem I antenna, 2) an even stronger decrease in the fluorescence of photosystem II, which was mediated by an increased spillover (kT(III)) of excitation to photosystem I and an increase in the absorption cross section, α, for photosystem I. We hypothesize that the increase of both kT(III) and α are part of a mechanism by which the desiccation-tolerant, high light exposed, Porphyra can avoid photodynamic damage to photosystem II, when photosynthesis becomes inhibited as a result of desiccation during periods of low tide.