State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan, 250100, China.
Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
Sci Rep. 2017 Aug 17;7(1):8542. doi: 10.1038/s41598-017-08428-6.
Nitrogen is one of the most important nutrients needed for plants and algae to survive, and the photosynthetic ability of algae is related to nitrogen abundance. Red algae are unique photosynthetic eukaryotic organisms in the evolution of algae, as they contain phycobilisomes (PBSs) on their thylakoid membranes. In this report, the in vivo chlorophyll (Chl) a fluorescence kinetics of nitrogen-starved Porphyridium cruentum were analyzed to determine the effects of nitrogen deficiency on photosynthetic performance using a multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer. Due to nitrogen starvation, the photochemical efficiency of PSII and the activity of PSII reaction centers (RCs) decreased, and photoinhibition of PSII occurred. The water-splitting system on the donor side of PSII was seriously impacted by nitrogen deficiency, leading to the inactivation of the oxygen-evolving complex (OEC) and decreased light energy conversion efficiency. In nitrogen-starved cells, a higher proportion of energy was used for photochemical reactions, and thermal dissipation was reduced, as shown by qP and qN. The ability of nitrogen-starved cells to tolerate and resist high photon flux densities was weakened. Our results showed that the photosynthetic performance of P. cruentum was severely impacted by nitrogen deficiency.
氮是植物和藻类生存所需的最重要的营养物质之一，而藻类的光合作用能力与氮的丰度有关。红藻是藻类进化过程中独特的光合真核生物，因为它们的类囊体膜上含有藻胆体（PBS）。在本报告中，使用多色脉冲幅度调制（PAM）叶绿素荧光仪分析了缺氮条件下紫球藻（Porphyridium cruentum）的体内叶绿素（Chl）a 荧光动力学，以确定氮缺乏对光合作用性能的影响。由于氮饥饿，PSII 的光化学效率和 PSII 反应中心（RC）的活性降低，并且 PSII 发生光抑制。氮饥饿严重影响 PSII 供体侧的水分解系统，导致产氧复合物（OEC）失活和光能转化效率降低。在氮饥饿的细胞中，更多的能量用于光化学反应，而热耗散减少，如 qP 和 qN 所示。氮饥饿细胞耐受和抵抗高光量子通量密度的能力减弱。我们的结果表明，氮饥饿严重影响了紫球藻的光合作用性能。
