Diel and seasonal changes in fluorescence rise kinetics of three scleractinian corals

Hill, R; Ralph, PJ

Diel and seasonal changes in fluorescence rise kinetics of three scleractinian corals

Hill, R

Ralph, PJ

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Publication Type:: Journal Article
Citation:: Functional Plant Biology, 2005, 32 (6), pp. 549 - 559
Issue Date:: 2005-07-28

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Field	Value	Language
dc.contributor.author	Hill, R https://orcid.org/0000-0002-4623-1563	en_US
dc.contributor.author	Ralph, PJ https://orcid.org/0000-0002-3103-7346	en_US
dc.date.issued	2005-07-28	en_US
dc.identifier.citation	Functional Plant Biology, 2005, 32 (6), pp. 549 - 559	en_US
dc.identifier.issn	1445-4408	en_US
dc.identifier.uri	http://hdl.handle.net/10453/3712
dc.description.abstract	The effect of diel oscillations in light on the photosynthetic response of three coral species during summer and winter was studied. Fast induction curves revealed detailed information on primary photochemistry as well as redox states of electron acceptors in photosystem II (PSII). The comparison between seasons revealed that similar physiological mechanisms were operating in response to high-light conditions throughout the year and that environmental variables, such as temperature, had no measurable effect between seasons. A diurnal hysteresis was seen in both seasons in Fv/Fm as well as in the fast induction curves, where photosynthetic capacity was lower in the afternoon than in the morning when light intensities were the same. This suggests the operation of dynamic down regulation, following exposure to midday high light. Fast induction curve analysis revealed a decline in the O, J, I and P steps towards midday and a rapid recovery by the late afternoon. The decrease in J and its rapid recovery indicated a drop in the rate of QA reduction as a result of an increase in non-photochemical quenching (NPQ). The P step increased in amplitude in the first hours of sunlight, which suggests an increased oxidation of the plastoquinone (PQ) pool and a greater capacity for electron transport. Similarly, a rise in Fv/Fm was observed within the first hour of sunlight. This response was attributed to the dark reduction of the PQ pool, induced by night time anaerobic conditions and possibly oxygen-dependent chlororespiration, which would lead to a state 2 transition. The early morning removal of chlororespiration and hypoxic conditions would have returned the photosystems to state 1, resulting in the increased photochemical efficiency of the zooxanthellae. © CSIRO 2005.	en_US
dc.relation	http://purl.org/au-research/grants/arc/DP0558946
dc.relation.ispartof	Functional Plant Biology	en_US
dc.relation.isbasedon	10.1071/FP05017	en_US
dc.subject.classification	Plant Biology & Botany	en_US
dc.title	Diel and seasonal changes in fluorescence rise kinetics of three scleractinian corals	en_US
dc.type	Journal Article
utslib.citation.volume	6	en_US
utslib.citation.volume	32	en_US
utslib.for	060701 Phycology (incl. Marine Grasses)	en_US
utslib.for	0601 Biochemistry and Cell Biology	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0607 Plant Biology	en_US
dc.location.activity	UNIV SYDNEY, SYDNEY, AUSTRALIA
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	closed_access
pubs.issue	6	en_US
pubs.publication-status	Published	en_US
pubs.volume	32	en_US

Abstract:

The effect of diel oscillations in light on the photosynthetic response of three coral species during summer and winter was studied. Fast induction curves revealed detailed information on primary photochemistry as well as redox states of electron acceptors in photosystem II (PSII). The comparison between seasons revealed that similar physiological mechanisms were operating in response to high-light conditions throughout the year and that environmental variables, such as temperature, had no measurable effect between seasons. A diurnal hysteresis was seen in both seasons in Fv/Fm as well as in the fast induction curves, where photosynthetic capacity was lower in the afternoon than in the morning when light intensities were the same. This suggests the operation of dynamic down regulation, following exposure to midday high light. Fast induction curve analysis revealed a decline in the O, J, I and P steps towards midday and a rapid recovery by the late afternoon. The decrease in J and its rapid recovery indicated a drop in the rate of QA reduction as a result of an increase in non-photochemical quenching (NPQ). The P step increased in amplitude in the first hours of sunlight, which suggests an increased oxidation of the plastoquinone (PQ) pool and a greater capacity for electron transport. Similarly, a rise in Fv/Fm was observed within the first hour of sunlight. This response was attributed to the dark reduction of the PQ pool, induced by night time anaerobic conditions and possibly oxygen-dependent chlororespiration, which would lead to a state 2 transition. The early morning removal of chlororespiration and hypoxic conditions would have returned the photosystems to state 1, resulting in the increased photochemical efficiency of the zooxanthellae. © CSIRO 2005.

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http://hdl.handle.net/10453/3712