TY  - JOUR
AU  - Matsubara, S.
AU  - Chen, Y.-C.
AU  - Caliandro, R.
AU  - Govindjee, G.
AU  - Clegg, R.M.
TI  - Photosystem II fluorescence lifetime imaging in avocado leaves: Contributions of the lutein-epoxide and violaxanthin cycles to fluorescence quenching
JO  - Journal of photochemistry and photobiology / B
VL  - 104
SN  - 1011-1344
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - PreJuSER-14173
PY  - 2011
N1  - 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.
AB  - 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.
KW  - Diuron: pharmacology
KW  - Hydrogen-Ion Concentration
KW  - Light
KW  - Lutein: chemistry
KW  - Microscopy, Fluorescence
KW  - Persea: enzymology
KW  - Photosystem II Protein Complex: chemistry
KW  - Photosystem II Protein Complex: metabolism
KW  - Plant Leaves: drug effects
KW  - Plant Leaves: enzymology
KW  - Time Factors
KW  - Xanthophylls: chemistry
KW  - Photosystem II Protein Complex (NLM Chemicals)
KW  - Xanthophylls (NLM Chemicals)
KW  - violaxanthin (NLM Chemicals)
KW  - Lutein (NLM Chemicals)
KW  - Diuron (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:21356597
UR  - <Go to ISI:>//WOS:000292066000027
DO  - DOI:10.1016/j.jphotobiol.2011.01.003
UR  - https://juser.fz-juelich.de/record/14173
ER  -