論文

査読有り
2019年7月

Partially dissecting electron fluxes in both photosystems in spinach leaf discs during photosynthetic induction

Plant and Cell Physiology
  • Meng-Meng Zhang
  • ,
  • Da-Yong Fan
  • ,
  • Keach Murakami
  • ,
  • Murray R Badger
  • ,
  • Guang-Yu Sun
  • ,
  • Wah Soon Chow

DOI
10.1093/pcp/pcz114
出版者・発行元
Oxford University Press ({OUP})

&lt;jats:title&gt;Abstract&lt;/jats:title&gt;<br />
&lt;jats:p&gt;Photosynthetic induction, a gradual increase in photosynthetic rate on transition from darkness or low light to high light, has ecological significance, impact on biomass accumulation in fluctuating light and relevance to photoprotection in strong light. However, experimental quantification of the component electron fluxes in/around both photosystems during induction has been rare. Combining optimized chlorophyll fluorescence, the redox kinetics of P700 (primary electron donor in Photosystem I, PSI) and membrane inlet mass spectrometry in the absence/presence of inhibitors/mediator, we partially estimated the components of electron fluxes in spinach leaf discs on transition from darkness to 1000 µmol photons m−2 s−1 for up to 10 min, obtaining the following findings: (1) the partitioning of energy between both photosystems did not change noticeably; (2) in PSII, the combined cyclic electron flow (CEF2) and charge recombination (CR2) to the ground state decreased gradually towards zero in steady state; (3) oxygen reduction by electrons from PSII, partly bypassing PSI, was small but measurable; (4) cyclic electron flow around PSI (CEF1) peaked before becoming somewhat steady; (5) peak magnitudes of some of the electron fluxes, all probably photoprotective, were in the descending order: CEF1 &amp;gt; CEF2 + CR2 &amp;gt; chloroplast O2 uptake; and (6) the chloroplast NADH dehydrogenase-like complex appeared to aid the antimycin A-sensitive CEF1. The results are important for fine-tuning in silico simulation of in vivo photosynthetic electron transport processes; such simulation is, in turn, necessary to probe partial processes in a complex network of interactions in response to environmental changes.&lt;/jats:p&gt;

リンク情報
DOI
https://doi.org/10.1093/pcp/pcz114
URL
http://orcid.org/0000-0001-8150-9535

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