Towards an understanding of species-specific differences in the photon use efficiency of diatoms

硅藻是一种重要的生态藻类，对全球变暖有着重要的影响，因为它们贡献了全球初级生产力的25%。光合机构在许多方面不同于绿色植物，并且响应于光和碳限制而调节碳同化的生理机制仍然未知。最近，生态类型的硅藻已被确定不同的光保护非光化学荧光淬灭（NPQ）的动力学和机制，以及在他们的利用C3-或C4-途径的初级碳固定。然而，当细胞在动态光气候和次优碳可用性下生长时，关于不同NPQ机制和C3/C4羧化对光子利用效率的影响一无所知。在这些条件下的光子利用效率的理解是至关重要的生物光学模型，特别是通过基于荧光的数据集的手段，在现场条件下的硅藻的初级生产的确定。结果将澄清硅藻中不同碳同化途径的定量重要性，并将提高基于荧光的初级生产模型的适用性。

Diatoms are an ecologically important group of algae having significant impact on global warming, because they contribute about 25% to the global primary production. The photosynthetic apparatus differs in many aspects from green plants and the physiological mechanisms which regulate the carbon assimilation in response to light and carbon limitation are still unknown. Recently, ecotypes of diatoms have been identified which differ in the kinetics and mechanisms of the photoprotective non-photochemical fluorescence quenching (NPQ) as well as in their utilization of the C3- or the C4-pathway for primary carbon fixation. However, nothing is known about the consequences of the different NPQ-mechanisms and the C3/C4 carboxylation on the photon use efficiency when the cells are grown under a dynamic light climate and suboptimal carbon availability. The understanding of the photon use efficiency under these conditions is of crucial importance for the determination of the primary production of diatoms under field conditions by bio-optical models, and in particular by means of fluorescence-based data sets. The results will clarify the quantitative importance of the different carbon assimilation pathways in diatoms and will improve the applicability of fluorescence-based models of primary production for the future.