The physiological response of seven strains of picophytoplankton to light, and its representation in a dynamic photosynthesis model
The physiological response of seven strains of picophytoplankton to light, and its representation in a dynamic photosynthesis model
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DOI：
10.1002/lno.10745
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发表时间：
2018-03
影响因子：
4.5
通讯作者：
Beate Stawiarski;E. Buitenhuis;Mehera Fallens
中科院分区：
文献类型：
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作者：
Beate Stawiarski;E. Buitenhuis;Mehera Fallens
浮游藻类在广阔的海洋区域中占主导地位，并且与其他浮游植物群体相比，被认为在获取光方面是有效的。为了量化它们的生理参数，我们使用了三株微微原核生物和四株微微真核生物。我们测量的指数生长率和叶绿素a（Chl a）碳比的驯化反应，以及在5-7光强度的光合速率的瞬时响应。然后，我们使用一个动态光合作用模型（盖德等人），并扩展它与光抑制项。本文导出了五个生理参数：最大光合速率（PmC）、对光的亲和力（αchl）、光抑制项（βchl）、呼吸速率（resp）和最大Chl a/C比（θmax）。我们发现，PmC是显着低于微微原核生物比微微真核生物，并显着增加细胞大小。反过来，αchl随着最大生长速率（μmax）的增加而显著降低。后一项发现与先前报道的浮游植物关系相反，但与基于大小的理论假设一致。光获取的更高效率使微微原核生物在光有限的环境中具有优势，但以牺牲其最大生长速率为代价。此外，我们的研究结果表明，在驯化过程中，通过光抑制的长期损害的积累并不能很好地代表动态光合作用模型。因此，我们建议区分不可逆损害（以天为时间尺度）对生长速率的影响和可逆损害（以分钟为时间尺度）对光合作用速率的影响。
Picophytoplankton dominate the phytoplankton community in wide ocean areas and are considered efficient in the acquisition of light compared to other phytoplankton groups. To quantify their photophysiological parameters we use three strains of picoprokaryotes and four strains of picoeukaryotes. We measure the acclimated response of the exponential growth rates and chlorophyll a (Chl a) to carbon ratios, as well as the instantaneous response of photosynthesis rates at 5–7 light intensities. We then use a dynamic photosynthesis model (Geider et al. ) and extend it with a photoinhibition term. We derive five photophysiological parameters: the maximum rate of photosynthesis ( PmC ), the affinity to light (αchl), the photoinhibition term (βchl), the respiration rate (resp), and the maximum Chl a to carbon ratio (θmax). We show that PmC is significantly lower for picoprokaryotes than for picoeukaryotes and increases significantly with increasing cell size. In turn, αchl decreases significantly with increasing maximum growth rate (μmax). The latter finding is contrary to a previously reported relationship for phytoplankton, but agrees with theoretical assumptions based on size. The higher efficiency in light acquisition gives picoprokaryotes an advantage in light limited environments at the expense of their maximum growth rate. In addition, our results indicate that the accumulation of long‐term damage through photoinhibition during acclimation is not well represented by the dynamic photosynthesis model. Hence, we would recommend to distinguish between the effects of irreversible damage (on a time scale of days) on growth rates and of reversible damage (on a time scale of minutes) on photosynthesis rates.