Photophysiological responses of fragilariopsis cylindrus (bacillariophyceae) to nitrogen depletion at two temperatures

Petrou, K; Kranz, SA; Doblin, MA; Ralph, PJ

Photophysiological responses of fragilariopsis cylindrus (bacillariophyceae) to nitrogen depletion at two temperatures

Petrou, K

Kranz, SA Doblin, MA

Ralph, PJ

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Publication Type:: Journal Article
Citation:: Journal of Phycology, 2012, 48 (1), pp. 127 - 136
Issue Date:: 2012-02-01

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Field	Value	Language
dc.contributor.author	Petrou, K https://orcid.org/0000-0002-2703-0694	en_US
dc.contributor.author	Kranz, SA	en_US
dc.contributor.author	Doblin, MA https://orcid.org/0000-0001-8750-3433	en_US
dc.contributor.author	Ralph, PJ https://orcid.org/0000-0002-3103-7346	en_US
dc.date.issued	2012-02-01	en_US
dc.identifier.citation	Journal of Phycology, 2012, 48 (1), pp. 127 - 136	en_US
dc.identifier.issn	0022-3646	en_US
dc.identifier.uri	http://hdl.handle.net/10453/18183
dc.description.abstract	The photosynthetic efficiency and photoprotective capacity of the sea-ice diatom, Fragilariopsis cylindrus (Grunow) W. Krieg., grown in a matrix of nitrogen repletion and depletion at two different temperatures (-1°C and +6°C) was investigated. Temperature showed no significant effect on photosynthetic efficiency or photoprotection in F. cylindrus. Cultures under nitrogen depletion showed enhanced photoprotective capacity with an increase in nonphotochemical quenching (NPQ) when compared with nitrogen-replete cultures. This phenomenon was achieved at no apparent cost to the photosynthetic efficiency of PSII (F V/F M). Nitrogen depletion yielded a partially reduced electron transport chain in which maximum fluorescence (F M) could only be obtained by adding 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). reoxidation curves showed the presence of Q B nonreducing PSII centers under nitrogen depletion. Fast induction curves (FICs) and electron transport rates (ETRs) revealed slowing of the electrons transferred from the primary (Q A) to the secondary (Q B) quinone electron acceptors of PSII. The data presented show that nitrogen depletion in F. cylindrus leads to the formation of Q B nonreducing PSII centers within the photosystem. On a physiological level, the formation of Q B nonreducing PSII centers in F. cylindrus provides the cell with protection against photoinhibition by facilitating the rapid induction of NPQ. This strategy provides an important ecological advantage, especially during the Antarctic spring, maintaining photosynthetic efficiency under high light and nutrient-limiting conditions. © 2011 Phycological Society of America.	en_US
dc.relation	http://purl.org/au-research/grants/arc/DP0773558
dc.relation.ispartof	Journal of Phycology	en_US
dc.relation.isbasedon	10.1111/j.1529-8817.2011.01107.x	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Photophysiological responses of fragilariopsis cylindrus (bacillariophyceae) to nitrogen depletion at two temperatures	en_US
dc.type	Journal Article
utslib.citation.volume	1	en_US
utslib.citation.volume	48	en_US
utslib.for	0607 Plant Biology	en_US
utslib.for	0704 Fisheries Sciences	en_US
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/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	closed_access
pubs.issue	1	en_US
pubs.publication-status	Published	en_US
pubs.volume	48	en_US

Abstract:

The photosynthetic efficiency and photoprotective capacity of the sea-ice diatom, Fragilariopsis cylindrus (Grunow) W. Krieg., grown in a matrix of nitrogen repletion and depletion at two different temperatures (-1°C and +6°C) was investigated. Temperature showed no significant effect on photosynthetic efficiency or photoprotection in F. cylindrus. Cultures under nitrogen depletion showed enhanced photoprotective capacity with an increase in nonphotochemical quenching (NPQ) when compared with nitrogen-replete cultures. This phenomenon was achieved at no apparent cost to the photosynthetic efficiency of PSII (F V/F M). Nitrogen depletion yielded a partially reduced electron transport chain in which maximum fluorescence (F M) could only be obtained by adding 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). reoxidation curves showed the presence of Q B nonreducing PSII centers under nitrogen depletion. Fast induction curves (FICs) and electron transport rates (ETRs) revealed slowing of the electrons transferred from the primary (Q A) to the secondary (Q B) quinone electron acceptors of PSII. The data presented show that nitrogen depletion in F. cylindrus leads to the formation of Q B nonreducing PSII centers within the photosystem. On a physiological level, the formation of Q B nonreducing PSII centers in F. cylindrus provides the cell with protection against photoinhibition by facilitating the rapid induction of NPQ. This strategy provides an important ecological advantage, especially during the Antarctic spring, maintaining photosynthetic efficiency under high light and nutrient-limiting conditions. © 2011 Phycological Society of America.

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