Role of Plastoquinone Redox State in Plants Response Under High Temperature

The Effect Of High Temperature Treatment (40°C, 3 H, Illumination At 100 μMol M-2 S-1) On The Photosynthetic Electron Flow In Thylakoids Of Barley Seedlings Was Investigated. The Thermoinduced Partial Inhibition Of Electron Flow On Psii Acceptor Side Was Shown By Measurements Of Oxygen Evolution Using Of Benzoquinone Or Potassium Ferricyanide As Electron Acceptors And Following QA - Reoxidation Kinetics In Absence And Presence Exogenous Electron Acceptors Dcbq And Dmbq. Using Hplc Analysis, The Increase In Oxidation Of Photoactive Plastoquinone Pool Under Heating Was Shown. It Is Proposed That Thermoinduced Change Of Redox State Of Pq-Pool And Redistribution Of Plastoquinone Molecules Between Photoactive And Non-Photoactive Pools Are The Mechanisms Regulating Response Of The Photosynthetic Apparatus On Stress Reactions.