Comparison of the light‐limited growth of the nitrogen‐fixing cyanobacteria Anabaena and Aphanizomenon

摘要: The effect of simultaneous N2 fixation and light limitation on the growth two strains Anabaena sp. Bory de St. Vincent Aphanizomenon flos-aquae (L.) Ralfs was investigated using continuous cultures. Under severely light-limited conditions, showed a broader absorption spectrum (due to presence phycoerythrin), higher maximum efficiency photosynthesis, steady-state activity affinity for than did Anabaena. On other hand, under saturation, rate O2 production specific Aphanizomenon. These monoculture results characterize Aphanizomenon, in relative terms, as ‘sun’ ‘shade’ species respectively, are accordance with field observations. difference between their acclimatory response is discussed terms species-specific alteration PSI∶PSII stoichiometry. Besides modulation accessory pigments, such an acclimation would provide biochemical basis observed physiological differences. were used differentiate niches suggested that competitively displace N2-fixing, conditions. However, when both grown together, became dominant seemed be superior competitor light. In order explain this finding, possible effects release allelopathic compounds, or dynamic aspects supply, discussed.