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@ARTICLE{Matsubara:14173,
author = {Matsubara, S. and Chen, Y.-C. and Caliandro, R. and
Govindjee, G. and Clegg, R.M.},
title = {{P}hotosystem {II} fluorescence lifetime imaging in avocado
leaves: {C}ontributions of the lutein-epoxide and
violaxanthin cycles to fluorescence quenching},
journal = {Journal of photochemistry and photobiology / B},
volume = {104},
issn = {1011-1344},
address = {New York, NY [u.a.]},
publisher = {Elsevier},
reportid = {PreJuSER-14173},
year = {2011},
note = {The research stay of S.M. at University of Illinois at
Urbana-Champaign was supported by a Deutsche Akademische
Austauschdienst (DAAD) travel grant (PPP-USA, D/07/10566).
Y.-C.C. was supported by the Taiwan Merit Scholarships
(TMS-094-1-A-036). G. was supported by the Department of
Plant Biology at the University of Illinois at
Urbana-Champaign. We thank Kelly Gillespie and Lisa
Ainsworth (Department of Plant Biology, University of
Illinois at Urbana-Champaign) for their help in
freeze-drying the leaf disc samples. R.M.C. thanks the
Research Board at UIUC for support. Although data were not
included in this work, friendly and expert assistance by
Mayandi Sivaguru (Microscopy and Imaging Facility, Institute
for Genomic Biology, University of Illinois at
Urbana-Champaign) for spinning disc confocal microscopy
experiments is greatly acknowledged.},
abstract = {Lifetime-resolved imaging measurements of chlorophyll a
fluorescence were made on leaves of avocado plants to study
whether rapidly reversible ΔpH-dependent (transthylakoid
H(+) concentration gradient) thermal energy dissipation (qE)
and slowly reversible ΔpH-independent fluorescence
quenching (qI) are modulated by lutein-epoxide and
violaxanthin cycles operating in parallel. Under normal
conditions (without inhibitors), analysis of the chlorophyll
a fluorescence lifetime data revealed two major lifetime
pools (1.5 and 0.5 ns) for photosystem II during the ΔpH
build-up under illumination. Formation of the 0.5-ns pool
upon illumination was correlated with dark-retention of
antheraxanthin and photo-converted lutein in leaves.
Interconversion between the 1.5- and 0.5-ns lifetime pools
took place during the slow part of the chlorophyll a
fluorescence transient: first from 1.5 ns to 0.5 ns in the
P-to-S phase, then back from 0.5 ns to 1.5 ns in the S-to-M
phase. When linear electron transport and the resulting ΔpH
build-up were inhibited by treatment with
3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), the major
fluorescence intensity was due to a 2.2-ns lifetime pool
with a minor faster contribution of approximately 0.7 ns. In
the presence of DCMU, neither the intensity nor the
lifetimes of fluorescence were affected by antheraxanthin
and photo-converted lutein. Thus, we conclude that both
antheraxanthin and photo-converted lutein are able to
enhance ΔpH-dependent qE processes that are associated with
the 0.5-ns lifetime pool. However, unlike zeaxanthin,
retention of antheraxanthin and photo-converted lutein may
not by itself stabilize quenching or cause qI.},
keywords = {Diuron: pharmacology / Hydrogen-Ion Concentration / Light /
Lutein: chemistry / Microscopy, Fluorescence / Persea:
enzymology / Photosystem II Protein Complex: chemistry /
Photosystem II Protein Complex: metabolism / Plant Leaves:
drug effects / Plant Leaves: enzymology / Time Factors /
Xanthophylls: chemistry / Photosystem II Protein Complex
(NLM Chemicals) / Xanthophylls (NLM Chemicals) /
violaxanthin (NLM Chemicals) / Lutein (NLM Chemicals) /
Diuron (NLM Chemicals) / J (WoSType)},
cin = {IBG-2},
ddc = {570},
cid = {I:(DE-Juel1)IBG-2-20101118},
pnm = {Terrestrische Umwelt},
pid = {G:(DE-Juel1)FUEK407},
shelfmark = {Biochemistry $\&$ Molecular Biology / Biophysics},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:21356597},
UT = {WOS:000292066000027},
doi = {10.1016/j.jphotobiol.2011.01.003},
url = {https://juser.fz-juelich.de/record/14173},
}