A common partitioning strategy for photosynthetic products in evolutionarily distinct phytoplankton species
A common partitioning strategy for photosynthetic products in evolutionarily distinct phytoplankton species
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DOI：
10.1111/nph.12209
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发表时间：
2013-06-01
期刊：
影响因子：
9.4
通讯作者：
Behrenfeld, Michael J.
中科院分区：
文献类型：
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作者：
Halsey, Kimberly H.;O'Malley, Robert T.;Behrenfeld, Michael J.
我们比较营养依赖的光合效率的绿藻，杜氏盐藻tertiolecta，与海洋硅藻，海链藻weissflorus。尽管有相当大的进化和生理差异，这两个物种似乎使用几乎相同的生长策略下广泛的营养限制。使用各种生理测量，我们发现，对于这两个物种，并在所有的增长率，总光合电子流的75%是投资于碳固定，只有30%保留为净碳积累。总光合作用的大部分（70%）最终用作生物合成途径和ATP生成的还原剂。在这两种物种中，新形成的碳产物在缓慢生长速率下比在快速生长速率下表现出短得多的半衰期。我们表明，这种生长速度依赖性是由于增加多糖储存在细胞周期的S期。我们提出了一个模型的碳利用，结合这种增长率依赖的碳分配和准确地捕捉（r2=0.94）所观察到的时间分辨的碳保留。总之，我们的研究结果表明，一个共同的光合优化策略在进化上不同的浮游植物物种，并有助于在光合自养生物的碳流的系统水平的理解。
We compare the nutrient-dependent photosynthetic efficiencies of the chlorophyte, Dunaliella tertiolecta, with those of the marine diatom, Thalassiosira weissflogii. Despite considerable evolutionary and physiological differences, these two species appear to use nearly identical growth strategies under a wide range of nutrient limitation. Using a variety of physiological measurements, we find that, for both species and across all growth rates, 75% of the gross photosynthetic electron flow is invested in carbon fixation and only 30% is retained as net carbon accumulation. A majority of gross photosynthesis (70%) is ultimately used as reductant for biosynthetic pathways and for the generation of ATP. In both species, newly formed carbon products exhibit much shorter half-lives at slow growth rates than at fast growth rates. We show that this growth rate dependence is a result of increased polysaccharide storage during the S phase of the cell cycle. We present a model of carbon utilization that incorporates this growth rate-dependent carbon allocation and accurately captures (r2=0.94) the observed time-resolved carbon retention. Together, our findings suggest a common photosynthetic optimization strategy in evolutionarily distinct phytoplankton species and contribute towards a systems-level understanding of carbon flow in photoautotrophs.