Apparent light requirement for activation of photosynthesis upon rehydration of desiccated beachrock microbial mats

Ulrich Schreiber; Rolf Gademann; Paul Bird; P.J. Ralph; A.W.D. Larkum; Michael Kühl

doi:10.1046/j.1529-8817.2002.01103.x

Apparent light requirement for activation of photosynthesis upon rehydration of desiccated beachrock microbial mats

Ulrich Schreiber, Rolf Gademann, Paul Bird, P.J. Ralph, A.W.D. Larkum, Michael Kühl

Marine Biological Section

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

64 Citationer (Scopus)

Abstract

Udgivelsesdato: February 2002

Originalsprog	Engelsk
Tidsskrift	Journal of Phycology
Vol/bind	38
Udgave nummer	1
Sider (fra-til)	125-134
ISSN	0022-3646
DOI	https://doi.org/10.1046/j.1529-8817.2002.01103.x
Status	Udgivet - 2002

Bibliografisk note

KEYWORDS
beachrock • cyanobacteria • photosynthesis • oxygen • chl fluorescence • microsensor • state 1/state 2

Adgang til dokumentet

10.1046/j.1529-8817.2002.01103.x

Citationsformater

@article{a73cca8074c511dbbee902004c4f4f50,

title = "Apparent light requirement for activation of photosynthesis upon rehydration of desiccated beachrock microbial mats",

abstract = "Photosynthetic electron transport of beachrock microbial mats growing in the intertidal zone of Heron Island (Great Barrier Reef, Australia) was investigated with a pulse amplitude modulation chl fluorometer providing four different excitation wavelengths for preferential excitation of the major algal groups (cyanobacteria, green algae, diatoms/dinoflagellates). A new type of fiberoptic emitter-detector unit (PHYTO-EDF) was used to measure chl fluorescence at the sample surface. Fluorescence signals mainly originated from cyanobacteria, which could be almost selectively assessed by 640-nm excitation. Even after desiccation for long time periods under full sunlight, beachrock showed rapid recovery of photosynthesis after rehydration in the light (t1/2~ 15 min). However, when rehydrated in the dark, the quantum yield of energy conversion of PSII remained zero over extended periods of time. Parallel measurements of O2 concentration with an oxygen microoptode revealed zero oxygen concentration in the surface layer of rehydrated beachrock in the dark. Upon illumination, O2 concentration increased in parallel with PSII quantum yield and decreased again to zero in the dark. It is proposed that oxygen is required for preventing complete dark reduction of the PSII acceptor pools via the NADPH-dehydrogenase/chlororespiration pathway. This hypothesis is supported by the observation that PSII quantum yield could be partially induced in the dark by flushing with molecular oxygen.Abbreviations: EDF, emitter-detector unit; Fo, fluor-escence yield of dark-adapted sample; Fm, maximal fluorescence yield measured during saturation pulse; Fv, variable fluorescence yield; LED, light-emitting diode; PAM, pulse amplitude modulation; PQ, plastoquinone",

author = "Ulrich Schreiber and Rolf Gademann and Paul Bird and P.J. Ralph and A.W.D. Larkum and Michael K{\"u}hl",

note = "KEYWORDS beachrock • cyanobacteria • photosynthesis • oxygen • chl fluorescence • microsensor • state 1/state 2",

year = "2002",

doi = "10.1046/j.1529-8817.2002.01103.x",

language = "English",

volume = "38",

pages = "125--134",

journal = "Journal of Phycology",

issn = "0022-3646",

publisher = "Wiley-Blackwell",

number = "1",

}

TY - JOUR

T1 - Apparent light requirement for activation of photosynthesis upon rehydration of desiccated beachrock microbial mats

AU - Schreiber, Ulrich

AU - Gademann, Rolf

AU - Bird, Paul

AU - Ralph, P.J.

AU - Larkum, A.W.D.

AU - Kühl, Michael

N1 - KEYWORDS beachrock • cyanobacteria • photosynthesis • oxygen • chl fluorescence • microsensor • state 1/state 2

PY - 2002

Y1 - 2002

N2 - Photosynthetic electron transport of beachrock microbial mats growing in the intertidal zone of Heron Island (Great Barrier Reef, Australia) was investigated with a pulse amplitude modulation chl fluorometer providing four different excitation wavelengths for preferential excitation of the major algal groups (cyanobacteria, green algae, diatoms/dinoflagellates). A new type of fiberoptic emitter-detector unit (PHYTO-EDF) was used to measure chl fluorescence at the sample surface. Fluorescence signals mainly originated from cyanobacteria, which could be almost selectively assessed by 640-nm excitation. Even after desiccation for long time periods under full sunlight, beachrock showed rapid recovery of photosynthesis after rehydration in the light (t1/2~ 15 min). However, when rehydrated in the dark, the quantum yield of energy conversion of PSII remained zero over extended periods of time. Parallel measurements of O2 concentration with an oxygen microoptode revealed zero oxygen concentration in the surface layer of rehydrated beachrock in the dark. Upon illumination, O2 concentration increased in parallel with PSII quantum yield and decreased again to zero in the dark. It is proposed that oxygen is required for preventing complete dark reduction of the PSII acceptor pools via the NADPH-dehydrogenase/chlororespiration pathway. This hypothesis is supported by the observation that PSII quantum yield could be partially induced in the dark by flushing with molecular oxygen.Abbreviations: EDF, emitter-detector unit; Fo, fluor-escence yield of dark-adapted sample; Fm, maximal fluorescence yield measured during saturation pulse; Fv, variable fluorescence yield; LED, light-emitting diode; PAM, pulse amplitude modulation; PQ, plastoquinone

AB - Photosynthetic electron transport of beachrock microbial mats growing in the intertidal zone of Heron Island (Great Barrier Reef, Australia) was investigated with a pulse amplitude modulation chl fluorometer providing four different excitation wavelengths for preferential excitation of the major algal groups (cyanobacteria, green algae, diatoms/dinoflagellates). A new type of fiberoptic emitter-detector unit (PHYTO-EDF) was used to measure chl fluorescence at the sample surface. Fluorescence signals mainly originated from cyanobacteria, which could be almost selectively assessed by 640-nm excitation. Even after desiccation for long time periods under full sunlight, beachrock showed rapid recovery of photosynthesis after rehydration in the light (t1/2~ 15 min). However, when rehydrated in the dark, the quantum yield of energy conversion of PSII remained zero over extended periods of time. Parallel measurements of O2 concentration with an oxygen microoptode revealed zero oxygen concentration in the surface layer of rehydrated beachrock in the dark. Upon illumination, O2 concentration increased in parallel with PSII quantum yield and decreased again to zero in the dark. It is proposed that oxygen is required for preventing complete dark reduction of the PSII acceptor pools via the NADPH-dehydrogenase/chlororespiration pathway. This hypothesis is supported by the observation that PSII quantum yield could be partially induced in the dark by flushing with molecular oxygen.Abbreviations: EDF, emitter-detector unit; Fo, fluor-escence yield of dark-adapted sample; Fm, maximal fluorescence yield measured during saturation pulse; Fv, variable fluorescence yield; LED, light-emitting diode; PAM, pulse amplitude modulation; PQ, plastoquinone

U2 - 10.1046/j.1529-8817.2002.01103.x

DO - 10.1046/j.1529-8817.2002.01103.x

M3 - Journal article

VL - 38

SP - 125

EP - 134

JO - Journal of Phycology

JF - Journal of Phycology

SN - 0022-3646

IS - 1

ER -