Original paper
Photosynthate partitioning: A labile, adaptive phenomenon in Microcystis aeruginosa
Olesen, T. D.; Ganf, G. G.
Archiv für Hydrobiologie Volume 108 Number 1 (1986), p. 55 - 76
29 references
published: Nov 25, 1986
DOI: 10.1127/archiv-hydrobiol/108/1986/55
ArtNo. ESP141010801003, Price: 29.00 €
Abstract
Short term (~ 1—2 h) measurements of photosynthesis for nutrient saturated batch cultures of Microcystis aeruginosa were shown to be representative of the rates occurring throughout the photoperiod, irrespective of previous conditioning. For cultures grown under constant daylength (10:14 L:D) and photon flux (300 µ moles m-2s-1) and exposed to a range of photon fluxes, the carbohydrate pool diminished at low irradiance but increased exponentially as photosynthesis increased. In contrast, protein synthesis asymptoted. Consequently, a greater proportion of the carbon fixed at low rates of photosynthesis was directed toward protein synthesis than to carbohydrate; at higher rates of photosynthesis the converse occurred. During the photoperiod there was a close relationship between protein synthesis and cell division. Respiration during the dark period was correlated linearly with carbohydrate concentration per cell at the end of the light period. Changes in the carbohydrate concentration during the dark period were related linearly to protein synthesis and cell division, and the specific growth rate was correlated linearly with respiration. Although carbohydrate per cell showed large fluctuation, protein content per cell remained constant throughout the 24 h. Photosynthesis of cultures preadapted to the conditions of exposure (1:23 to 24:0 L:D; 5—120 µ moles m-2s -1) was highest at a short photoperiod (62.8 f moles O2 cell-1 h-1) and least under continuous light; this trend was reflected by the rate of carbohydrate synthesis. There was no change in protein content per cell, as the rate of protein synthesis corresponded with the specific growth rate. Specific growth rates over 24 h increased with daylength; however rates corrected for the light received showed the reverse trend. A comparison between rates of photosynthesis and photosynthesis to respiration ratios in three cultures adapted to different conditions showed that Microcystis aeruginosa responded to changes in the light climate.
Keywords
photosynthesis • carbon • Microcystis aeruginosa