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

硅藻是一类重要的生态藻类，对全球变暖有重要影响，因为它们对全球初级生产力的贡献率约为25%。绿色植物的光合作用机制与绿色植物有许多不同之处，调节碳同化对光和碳限制的生理机制尚不清楚。最近，硅藻的生态型已经被鉴定出来，它们在光保护性非光化学荧光猝灭(NPQ)的动力学和机制以及它们利用C3-或C4-途径进行初级碳固定方面存在差异。然而，当细胞生长在动态光照气候和次优碳利用率下时，不同的NPQ机制和C3/C4羧化对光子利用效率的影响尚不清楚。了解这些条件下的光子利用效率对于通过生物光学模型，特别是通过基于荧光的数据集确定野外条件下硅藻的初级生产量至关重要。这一结果将阐明硅藻中不同碳同化途径的数量重要性，并将提高基于荧光的初级生产力模型在未来的适用性。

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.