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Effect of photoacclimation on the energy partitioning between cyclic and non‐cyclic photophosphorylation
Author(s) -
HERZIG RONNY,
DUBINSKY ZVY
Publication year - 1993
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1993.tb03775.x
Subject(s) - photophosphorylation , dcmu , oxidative phosphorylation , chemistry , photosynthesis , biophysics , electron transport chain , phosphorylation , botany , biochemistry , photosystem ii , chloroplast , biology , gene
SUMMARY The effect of photoacclimation on cyclic (CPP), non‐cyclic (NCPP), and oxidative phosphorylation was investigated in three algal species: Isochrisis galbana, Scenedesmus quadricauda and Synechococcus leopoliensis. The relative contribution of the three phosphorylative pathways to the incorporation of 32 P into soluble and particulate cellular pools was assessed. To block NCPP we used 1 μm dichlorophenyl‐dimethylurea (DCMU) which does not interrupt CPP. Oxidative phosphorylation was blocked by purging oxygen with N 2 . In all three species the ratio of CPP to the total photophosphorylation (PP) increased in the process of photoacclimation to high light. We suggest that the observed increase in CPP in high‐light‐adapted cells allows bypassing the relatively slow enzymatic reactions in NCPP while channelling excess electrons to the faster CPP. This redistribution of energy increases ATP supply for the augmented metabolic requirements of fast growing, high‐light‐adapted cells.