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.
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
Karel
K
Rohácek
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