Gordillo Francisco J L, Figueroa Félix L, Niell F Xavier
Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071 Málaga, Spain.
Planta. 2003 Dec;218(2):315-22. doi: 10.1007/s00425-003-1087-3. Epub 2003 Aug 21.
The seaweed Ulva rigida C. Agardh (Chlorophyta) was cultured under two CO(2) conditions supplied through the air bubbling system: non-manipulated air and 1% CO(2)-enriched aeration. These were also combined with N sufficiency and N limitation, using nitrate as the only N source. High CO(2) in U. rigida led to higher growth rates without increasing the C fixed through photosynthesis under N sufficiency. Quantum yields for charge separation at photosystem II (PSII) reaction centres (phi(PSII)) and for oxygen evolution (phi(O2)) decreased at high CO(2) even in N-sufficient thalli. Cyclic electron flow around PSII as part of a photoprotection strategy accompanied by decreased antennae size was suspected. The new re-arrangement of the photosynthetic energy at high CO(2) included reduced investment in processes other than C fixation, as well as in carbon diverted to respiration. As a result, quantum yield for new biomass-C production (phi(growth)) increased. The calculation of the individual quantum yields for the different processes involved allowed the completion of the energy flow scheme through the cell from incident light to biomass production for each of the CO(2) and N-supply conditions studied.
将石莼（绿藻门）在通过空气鼓泡系统提供的两种二氧化碳条件下培养：未处理的空气和1%二氧化碳富集通气。这些条件还分别与氮充足和氮限制相结合，以硝酸盐作为唯一的氮源。在氮充足的情况下，石莼中高浓度的二氧化碳导致更高的生长速率，而不会增加通过光合作用固定的碳量。即使在氮充足的藻体中，在高浓度二氧化碳条件下，光系统II（PSII）反应中心电荷分离的量子产率（φ(PSII)）和放氧的量子产率（φ(O2)）也会降低。怀疑作为光保护策略一部分的围绕PSII的循环电子流伴随着天线大小的减小。在高浓度二氧化碳条件下，光合能量的新重新分配包括减少对除碳固定以外的过程的投入，以及减少转向呼吸作用的碳量。结果，新生物量碳生产的量子产率（φ(生长)）增加。对所涉及的不同过程的单个量子产率进行计算，使得能够完成在每种研究的二氧化碳和氮供应条件下，从入射光到生物量生产的通过细胞的能量流方案。
