Fast reactivation of photosynthesis in arctic phytoplankton during the polar night1
Fast reactivation of photosynthesis in arctic phytoplankton during the polar night1
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DOI：
10.1111/jpy.12750
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发表时间：
2018-08-01
影响因子：
2.9
通讯作者：
Leu, Eva
中科院分区：
文献类型：
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作者：
Kvernvik, Ane Cecilie;Hoppe, Clara Jule Marie;Leu, Eva
北极微藻在极夜经历了长时间的持续黑暗，无法进行光合作用。尽管有许多关于越冬策略的研究，如储存能量产品的利用、静息期的形成、代谢率的降低和异养生活方式，但很少有人尝试评估重新照明后光合机构的原位生理状态和恢复。在本研究中，我们在北纬78度的极夜发现了多样化和活跃的海洋浮游植物群落，并且我们观察到光合电子传递效率在重新照明后的快速变化（20分钟）。再光照24h后，植株的光合能力和净初级产量均较高。我们的研究结果表明，一些北极自养生物在极夜期间保持完全功能的光系统II和下游电子受体，尽管1月份测量的原位净初级生产水平较低，证明光不足以支持任何可测量的初级生产。由于低温导致呼吸速率低，并且极夜期间没有光损伤，维持基本光合作用机制实际上可能对藻类细胞造成相对较低的代谢成本。这可以使北极微藻在没有形成休眠阶段的情况下忍受极夜，使它们能够在冬春过渡期间太阳回归时立即恢复并利用光线。
Arctic microalgae experience long periods of continuous darkness during the polar night, when they are unable to photosynthesize. Despite numerous studies on overwintering strategies, such as utilization of stored energy products, formation of resting stages, reduction of metabolic rates and heterotrophic lifestyles, there have been few attempts to assess the insitu physiological state and restoration of the photosynthetic apparatus upon re-illumination. In this study, we found diverse and active marine phytoplankton communities during the polar night at 78 degrees N. Furthermore, we observed rapid changes (20min) in the efficiency of photosynthetic electron transport upon re-illumination. High photosynthetic capacity and net primary production were established after 24h of re-illumination. Our results suggest that some Arctic autotrophs maintain fully functional photosystem II and downstream electron acceptors during the polar night even though the low insitu net primary production levels measured in January prove that light was not sufficient to support any measurable primary production. Due to low temperatures resulting in low respiratory rates as well as the absence of photodamage during the polar night, maintenance of basic photosynthetic machinery may actually pose relatively low metabolic costs for algal cells. This could allow Arctic microalgae to endure the polar night without the formation of dormant stages, enabling them to recover and take advantage of light immediately upon the suns return during the winter-spring transition.