phoosynthesis and fluorescence光合荧光.pptVIP

* * * * * * * * * * Chondrus crispus Hanelt et al. (1992) Fv/Fm – Diurnal and spatial variation Depth (m) Macrocystis pyrifera Colombo-Pallotta (2007) Littoral Littoral Sublittoral Sublittoral Sublittoral Sublittoral van de Poll et al. (2001) Fv/Fm – Comparison of stress responses between species 1 ? PS ? 0 1 ? NPQ ? 0 CHLOROPHYLL FLUORESCENCE MEASUREMENT Fv/Fm ?F/Fm’ PS = 0 1 ? NPQ ? 0 ?F/Fm’ – EFFECTIVE QUANTUM YIELD Used to describe the variation in the photochemical efficiency of PSII under illuminated conditions. Measurement of this parameter at certain irradiance value. ? Indicator of the ability of an organism to move electrons beyond PSII (ETR) ?F/Fm’ = (Fm’-F)/Fm’ ETR = Irradiance ? ?F/Fm’ ? 0,5 ? Absorptance (Genty et al. 1989) ?F/Fm’ = effective quantum yield (under light) 0,5 = Assumption that 50% of these quanta are absorbed by PSII Absorptance = fraction of incident light that is absorbed by the photosynthetic tissue. Not the same as absorbance (quantifies how much of the incident light is absorbed by an object). ELECTRON-TRANSPORT RATE (ETR)– CURVES ELECTRON-TRANSPORT RATE (ETR)– CURVES ETR = Irradiance ? ?F/Fm’ ? 0,5 ? Absorptance Relative ETR = Irradiance ? ?F/Fm’ ? 0,5 (Ralph et al. 2002) ETR: when absorption characteristics change between species, acclimations, seasons… - rel. ETR: use only when it is sure that there are no differences in the absorption characteristics Macrocystis pyrifera Colombo-Pallotta et al. (2006) ETR– CURVES AS AN ANALOGUE TO P-E- CURVES CHLOROPHYLL FLUORESCENCE EXTENSIVELY USE DUE TO: NON-DESTRUCTIVE NON-INVASIVE RAPID SENSITIVE IN REAL-TIME Since 1995 the number of articles published applying chlorophyll fluorescence on the analysis of the photosynthetic performance in macroalgae and seagrasses has increased more than five times. The Chl fluorometer should be capable of measuring the fluorescence yield in a non-intrusive way: very low measuring light (i.e. exciting light) intensity for assess