Nonphotochemical Quenching of Chlorophyll Fluorescence

摘要: Measurement of chlorophyll fluorescence is an invaluable method for examining the interaction photosynthetic organisms with their environment and non-invasive probing metabolism chloroplast (Krause & Weis, 1991; Horton Bowyer, 1990). Fluorescence, most which emitted from PSII chlorophylls at room temperature, can be quenched its maximum value, Fm, as found in a healthy dark adapted sample, either photochemically or nonphotochemically. Whereas photochemical quenching occurs due to process energy consumption electron transport, nonphotochemically general terms reflects change “state” apparatus — thus, measurement has provided evidence presence of, on one hand, regulatory mechanisms, other, inhibition damage thylakoid membrane under stress conditions. Nonphotochemical measured often decrease Fm value some new Fm’, this recorded any given steady state using modulated fluorimetry, laboratory field, by application brief saturating light pulse close centres (Quick Horton, 1984; Schreiber et al., 1986). If normalised qN then approaches direct proportionality rate dissipation (Demmig-Adams, 1990; Bilger Bjorkman, 1990); however, only strictly correct if Stern-Volmer type. Alternatively, calculated normalising F v ’ , case range 0 1 (Schreiber 1986; van Kooten Snel, disadvantage calculation that Fo’ needs determine Fv’, something quite difficult furthermore, becomes very insensitive increases high values.