Phosphorus, nitrogen, and carbon nutrition in fresh and starved gametophytes of the red alga Porphyra purpurea (Roth) C. Agardh and occurrence of polyphosphates.

摘要

Gametophytes of the red alga Porphyra purpurea (Roth) C. Agardh, a representative of the Bangiophyceae, were either directly incubated in enriched seawater [15 muM phosphorus (P) and 25 muM nitrogen (N)] for up to 72 h, or kept under controlled starvation conditions for a few weeks in order to decrease their initial content of tissue total P before being incubated in enriched seawater. The phenomenon of P overcompensation was recorded in P. purpurea under certain conditions, depending on the nutrient prehistory of the plants. Comparison of the contents of the different phosphorylated fractions between P. purpurea and Chondrus crispus, a representative of the Florideophyceae, considered the more advanced of the two classes of the Rhodophyta, point towards P. purpurea being a much more metabolically active P "pump" than C. crispus, with a higher P turnover rate, in which the orthophosphate fraction is predominant. (Abstract shortened by UMI.).