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Photoinhibition of respiratory CO 2 release in the green alga Scenedesmus
Author(s) -
Scherer Siegfried,
Stürzl Erwin,
Böger Peter
Publication year - 1984
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.1399-3054.1984.tb04927.x
Subject(s) - cyanide , carbon dioxide , respiration , scenedesmus , photoinhibition , oxygen evolution , dcmu , scenedesmus obliquus , bicarbonate , oxygen , photosynthesis , phototroph , total inorganic carbon , chemistry , botany , photochemistry , biophysics , biology , algae , photosystem ii , inorganic chemistry , organic chemistry , electrode , electrochemistry
14 CO 2 evolution of prelabeled Scenedesmus obliquus Kütz, has been followed in the dark and in the light. In the light, no carbon dioxide is evolved. Addition of unlabeled NaHCO, leads to 14 CO 2 release attaining 20 to 30% of the dark rate. Double‐reciprocal plots of NaHCO 3 concentrations vs 14 CO 2 release results in a straight line, indicative of competition between exogenously supplied bicarbonate and endogenously evolved carbon dioxide. With this method, it is possible to measure CO 2 evolved by respiration in the light and to show that true photoinhibition of respiration occurs in Scenedesmus . In the light. DCMU substantially increases 14 CO 2 evolution; in the presence of the uncoupler carbonyl cyanide‐ m ‐chlorophenylhydrazone. 14 CO 2 evolution is comparable to that in the dark. 14 CO 2 release and oxygen uptake in the dark are only slightly affected by cyanide, indicative of a cyanide‐resistant respiration and/or fermentation as the essential CO 2 ‐yielding processes in the presence of cyanide. These results, compared with concurrent ATP levels, lead us to assume that energy charge is not the only factor responsible for photoinhibition of respiration.