Redox transients of P680 associated with the incremental chlorophyll-a fluorescence yield rises elicited by a series of saturating flashes in diuron-treated photosystem II core complex of Thermosynechococcus vulcanus

Gábor Sipka, Pavel Müller, Klaus Brettel, Melinda Magyar, László Kovács, Qingjun Zhu, Yanan Xiao, Guangye Han, Petar H. Lambrev, Jian-Ren Shen, Győző Garab

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Recent chlorophyll-a fluorescence yield measurements, using single-turnover saturating flashes (STSFs), have revealed the involvement of a rate-limiting step in the reactions following the charge separation induced by the first flash. As also shown here, in diuron-inhibited PSII core complexes isolated from Thermosynechococcus vulcanus the fluorescence maximum could only be reached by a train of STSFs. In order to elucidate the origin of the fluorescence yield increments in STSF series, we performed transient absorption measurements at 819 nm, reflecting the photooxidation and re-reduction kinetics of the primary electron donor P680. Upon single flash excitation of the dark-adapted sample, the decay kinetics could be described with lifetimes of 17 ns (∼50%) and 167 ns (∼30%), and a longer-lived component (∼20%). This kinetics are attributed to re-reduction of P680 •+ by the donor side of PSII. In contrast, upon second-flash (with Δt between 5 μs and 100 ms) or repetitive excitation, the 819 nm absorption changes decayed with lifetimes of about 2 ns (∼60%) and 10 ns (∼30%), attributed to recombination of the primary radical pair P680 •+ Pheo •– , and a small longer-lived component (∼10%). These data confirm that only the first STSF is capable of generating stable charge separation – leading to the reduction of Q A ; and thus, the fluorescence yield increments elicited by the consecutive flashes must have a different physical origin. Our double-flash experiments indicate that the rate-limiting steps, detected by chlorophyll-a fluorescence, are not correlated with the turnover of P680.

Original languageEnglish
Pages (from-to)22-32
Number of pages11
JournalPhysiologia Plantarum
Volume166
Issue number1
DOIs
Publication statusPublished - May 1 2019

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Thermosynechococcus vulcanus
Diuron
diuron
Photosystem II Protein Complex
photosystem II
Oxidation-Reduction
Fluorescence
fluorescence
chlorophyll
kinetics
photooxidation
Genetic Recombination
deterioration
electrons
chlorophyll a
Electrons

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science
  • Cell Biology

Cite this

Redox transients of P680 associated with the incremental chlorophyll-a fluorescence yield rises elicited by a series of saturating flashes in diuron-treated photosystem II core complex of Thermosynechococcus vulcanus. / Sipka, Gábor; Müller, Pavel; Brettel, Klaus; Magyar, Melinda; Kovács, László; Zhu, Qingjun; Xiao, Yanan; Han, Guangye; Lambrev, Petar H.; Shen, Jian-Ren; Garab, Győző.

In: Physiologia Plantarum, Vol. 166, No. 1, 01.05.2019, p. 22-32.

Research output: Contribution to journalArticle

Sipka, Gábor ; Müller, Pavel ; Brettel, Klaus ; Magyar, Melinda ; Kovács, László ; Zhu, Qingjun ; Xiao, Yanan ; Han, Guangye ; Lambrev, Petar H. ; Shen, Jian-Ren ; Garab, Győző. / Redox transients of P680 associated with the incremental chlorophyll-a fluorescence yield rises elicited by a series of saturating flashes in diuron-treated photosystem II core complex of Thermosynechococcus vulcanus. In: Physiologia Plantarum. 2019 ; Vol. 166, No. 1. pp. 22-32.
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AU - Müller, Pavel

AU - Brettel, Klaus

AU - Magyar, Melinda

AU - Kovács, László

AU - Zhu, Qingjun

AU - Xiao, Yanan

AU - Han, Guangye

AU - Lambrev, Petar H.

AU - Shen, Jian-Ren

AU - Garab, Győző

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