It has been recently suggested that compensatory changes in Photosystem II (PS II) electron turnover rates can protect photosynthesis from photoinhibition [Behrenfeld et al. (1998) Photosynth Res 58: 259-268]. We have further explored this feature of PS II using a rate electrode for simultaneous measurements of the steady-state rate of oxygen evolution and the oxygen flash yield depending on the background irradiance in both control and photoinhibited algal cells of Chlorella Böhm. Theoretical simulations based on the two-electron gate model agree qualitatively with experimental data if we assume an increase of the electron turnover rate in the remaining functional PS II centers of the photoinhibited sample. Our results confirm the hypothesis that the compensatory effect enables cells to maintain the maximal rates of photosynthesis even in the presence of moderate photoinhibition (decrease of up to 50% in the number of functional centers) and that the effect originates from the inner capacity of electron transport through PS II. The origin of the compensatory effect is briefly discussed.

Faculty of Science Laboratory of Biophysics tr Palacký University Svobody 26 771 46 Olomouc Czech Republic

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Plant Physiol. 1986 Aug;81(4):1115-22 PubMed

Biochim Biophys Acta. 1956 Aug;21(2):234-44 PubMed

Biochim Biophys Acta. 2000 Jul 20;1459(1):148-68 PubMed

Plant Physiol. 1998 Mar;116(3):1053-61 PubMed

Plant Physiol. 1997 Sep;115(1):151-157 PubMed

Planta. 1988 Feb;173(2):267-74 PubMed

Biochim Biophys Acta. 1993 Jul 5;1143(2):113-34 PubMed

Photosynth Res. 1992 Jan;31(1):31-40 PubMed

Plant Physiol. 1971 Sep;48(3):282-6 PubMed

Biochim Biophys Acta. 1975 Jan 31;376(1):105-15 PubMed

Trends Biochem Sci. 1997 Sep;22(9):361-3 PubMed

J Gen Physiol. 1950 Mar;33(4):389-422 PubMed

Comput Appl Biosci. 1993 Oct;9(5):563-71 PubMed

Biochim Biophys Acta. 1999 May 26;1412(1):1-28 PubMed

Planta. 1990 Sep;182(2):161-8 PubMed

Plant Physiol. 1972 Jul;50(1):141-8 PubMed

Biochim Biophys Acta. 2000 Nov 20;1460(2-3):255-67 PubMed

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