simple chlorophyll fluorescence parameter that correlates with the rate coefficient of photoinactivation of Photosystem II

A method of partitioning the energy in a mixed population of active and photoinactivated Photosystem II (PS II) complexes based on chlorophyll fluorescence measurements is presented. There are four energy fluxes, each with its quantum efficiency: a flux associated with photochemical electron flow in...

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Bibliographic Details
Published in:Photosynthesis research 2005-06, Vol.84 (1-3), p.43-49
Main Authors: Hendrickson, L, Forster, B, Pogson, B.J, Chow, W.S
Format: Article
Language:English
Subjects:
Capsicum - metabolism
Capsicum annuum
Chlorophyll
Chlorophyll - metabolism
electron transport chain
energy metabolism
Fluorescence
intrinsic quantum efficiency of photosystem II
Light
light intensity
mathematical models
non-photochemical quenching
peppers
Photochemistry
photoinhibition
photosynthesis
photosynthetic reaction centers
photosystem II
Photosystem II Protein Complex - metabolism
Photosystem II Protein Complex - radiation effects
quantum efficiency
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Summary:A method of partitioning the energy in a mixed population of active and photoinactivated Photosystem II (PS II) complexes based on chlorophyll fluorescence measurements is presented. There are four energy fluxes, each with its quantum efficiency: a flux associated with photochemical electron flow in active PS II reaction centres (JPS II), thermal dissipation in photoinactivated, non-functional PS IIs (JNF), light-regulated thermal dissipation in active PS IIs (JNPQ) and a combined flux of fluorescence and constitutive, light-independent thermal dissipation (Jf,D). The four quantum efficiencies add up to 1.0, without the need to introduce an 'excess' term E, which in other studies has been claimed to be linearly correlated with the rate coefficient of photoinactivation of PS II (kpi). We examined the correlation of kpi with various fluxes, and found that the combined flux (JNPQ + Jf,D= Jpi) is as well correlated with kpi as is E. This combined flux arises from Fs/Fm ', the ratio of steady-state to maximum fluorescence during illumination, which represents the quantum efficiency of combined non-photochemical dissipation pathways in active PS IIs. Since Fs/Fm ' or its equivalent, Jpi, is a likely source of events leading to photoinactivation of PS II, we conclude that Fs/Fm ' is a simple predictor of kpi.
ISSN:0166-8595
1573-5079
DOI:10.1007/s11120-004-6430-4