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What physiological acclimation supports increased growth at high CO 2 conditions?
Author(s) -
Spijkerman Elly
Publication year - 2008
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2008.01062.x
Subject(s) - rubisco , photosynthesis , acclimatization , population , growth rate , yield (engineering) , quantum yield , biology , aeration , botany , chemistry , physics , ecology , thermodynamics , demography , geometry , mathematics , quantum mechanics , sociology , fluorescence
Chlamydomonas acidophila Negoro is a green algal species abundant in acidic waters (pH 2–3.5), in which inorganic carbon is present only as CO 2 . Previous studies have shown that aeration with CO 2 increased its maximum growth rate, suggesting CO 2 limitation under natural conditions. To unravel the underlying physiological mechanisms at high CO 2 conditions that enables increased growth, several physiological characteristics from high‐ and low‐CO 2 ‐acclimated cells were studied: maximum quantum yield, photosynthetic O 2 evolution (P max ), affinity constant for CO 2 by photosynthesis (K 0.5,p ), a CO 2 ‐concentrating mechanism (CCM), cellular Rubisco content and the affinity constant of Rubisco for CO 2 (K 0.5,r ). The results show that at high CO 2 concentrations, C. acidophila had a higher K 0.5,p , P max , maximum quantum yield, switched off its CCM and had a lower Rubisco content than at low CO 2 conditions. In contrast, the K 0.5,r was comparable under high and low CO 2 conditions. It is calculated that the higher P max can already explain the increased growth rate in a high CO 2 environment. From an ecophysiological point of view, the increased maximum growth rate at high CO 2 will likely not be realised in the field because of other population regulating factors and should be seen as an acclimation to CO 2 and not as proof for a CO 2 limitation.