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Post‐illumination transient O 2 ‐uptake is driven by photorespiration in tobacco leaves
Author(s) -
Sejima Takehiro,
Hanawa Hitomi,
Shimakawa Ginga,
Takagi Daisuke,
Suzuki Yuji,
Fukayama Hiroshi,
Makino Amane,
Miyake Chikahiro
Publication year - 2016
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12388
Subject(s) - photorespiration , photosynthesis , nicotiana tabacum , photosystem ii , chlorophyll fluorescence , rubisco , electron transport chain , botany , chemistry , steady state (chemistry) , respiration , biophysics , biology , horticulture , biochemistry , gene
This study aims to elucidate the molecular mechanism for the transient increase in the O 2 ‐uptake rate in tobacco ( Nicotiana tabacum cv Xanthi) leaves after turning off actinic lights ( ALs ). The photosynthetic O 2 evolution rate reaches a maximum shortly after the onset of illumination with ALs and then decreases to zero in atmospheric CO 2 / O 2 conditions. After turning off the ALs , tobacco leaves show a transient increase in the O 2 ‐uptake rate, the post‐illumination transient O 2 ‐uptake, and thereafter, the O 2 ‐uptake rate decreases to the level of the dark‐respiration rate. Photosynthetic linear electron flow, evaluated as the quantum yield of photosystem II [Y( II )], maintained a steady‐state value distinct from the photosynthetic O 2 ‐evolution rate. In high‐[ CO 2 ] conditions, the photosynthetic O 2 ‐evolution rate and Y( II ) showed a parallel behavior, and the post‐illumination transient O 2 ‐uptake was suppressed. On the other hand, in maize leaves (a C4 plant), even in atmospheric CO 2 / O 2 conditions, Y( II ) paralleled the photosynthetic O 2 ‐evolution rate and the post‐illumination transient O 2 ‐uptake was suppressed. Hypothesizing that the post‐illumination transient O 2 ‐uptake is driven by C3 plant photorespiration in tobacco leaves, we calculated both the ribulose 1,5‐bisphosphate carboxylase‐ and oxygenase‐rates (Vc and Vo) from photosynthetic O 2 ‐evolution and the post‐illumination transient O 2 ‐uptake rates. These values corresponded to those estimated from simultaneous chlorophyll fluorescence/ O 2 ‐exchange analysis. Furthermore, the H + ‐consumption rate for ATP synthesis in both photosynthesis and photorespiration, calculated from both Vc and Vo that were estimated from chlorophyll fluorescence/ CO 2 ‐exchange analysis, showed a positive linear relationship with the dissipation rate of the electrochromic shift signal. Thus, these findings support our hypothesis.

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