Method for resolution and quantification of components of the non-photochemical quenching (q (N)).
A new method of the chlorophyll (Chl) a fluorescence quenching analysis is described, which allows the calculation of values of (at least) three components of the non-photochemical quenching of the variable Chl a fluorescence (q (N)) using a non-linear regression of a multi-exponential function within experimental data. Formulae for coefficients of the "energy"-dependent (DeltapH-dependent) quenching (q (E)), the state-transition quenching (q (T)) and the photo/inhibitory quenching (q (I)) of Chl a fluorescence were found on the basis of three assumptions: (i) the dark relaxation kinetics of q (N), as well as of all its components, is of an exponential nature, (ii) the superposition principle is valid for individual Chl a fluorescence quenching processes and (iii) the same reference fluorescence level (namely the maximum variable Chl a fluorescence yield in the dark-adapted state, F (V)) is used to define both q (N) and its components. All definitions as well as the algorithms for analytical recognition of the q (N) components are theoretically clarified and experimentally tested. The described theory results in a rather simple equation allowing to compute values for all q (N) components (q (E), q (T), q (I)) as well as the half-times of relaxation (tau(1/2)) of corresponding quenching processes. It is demonstrated that under the above assumptions it holds: q (N) = q (E) + q (T) + q (I). The theoretically derived equations are tested, and the results obtained are discussed for non-stressed and stressed photosynthetically active samples. Semi-empirical formulae for a fast estimation of values of the q (N) components from experimental data are also given.
Rohácek
Karel
K
Biology Centre of the Academy of Sciences of the Czech Republic, p.r.i., Institute of Plant Molecular Biology, Branisovská 31, 370 05 Ceske Budejovice, Czech Republic. rohacek@umbr.cas.cz
D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D003624:Darkness; D005453:Fluorescence; D007700:Kinetics; D027805:Phaseolus / Q000378:metabolism*; D010777:Photochemistry / Q000379:methods*; D018515:Plant Leaves / Q000378:metabolism; D012044:Regression Analysis; D013997:Time Factors; D003313:Zea mays / Q000378:metabolism*
D002734:Chlorophyll; D000077194:Chlorophyll A