The acclimation of photosynthesis and respiration to temperature in the C3–C4 intermediate Salsola divaricata: induction of high respiratory CO2 release under low temperature |
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Authors: | ANTHONY GANDIN NURIA K KOTEYEVA ELENA V VOZNESENSKAYA GERALD E EDWARDS ASAPH B COUSINS |
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Institution: | 1. School of Biological Sciences, Molecular Plant Sciences, Washington State University, , Pullman, WA, 99164‐4236 USA;2. Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, , St. Petersburg, 197376 Russia |
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Abstract: | Photosynthesis in C3–C4 intermediates reduces carbon loss by photorespiration through refixing photorespired CO2 within bundle sheath cells. This is beneficial under warm temperatures where rates of photorespiration are high; however, it is unknown how photosynthesis in C3–C4 plants acclimates to growth under cold conditions. Therefore, the cold tolerance of the C3–C4 Salsola divaricata was tested to determine whether it reverts to C3 photosynthesis when grown under low temperatures. Plants were grown under cold (15/10 °C), moderate (25/18 °C) or hot (35/25 °C) day/night temperatures and analysed to determine how photosynthesis, respiration and C3–C4 features acclimate to these growth conditions. The CO2 compensation point and net rates of CO2 assimilation in cold‐grown plants changed dramatically when measured in response to temperature. However, this was not due to the loss of C3–C4 intermediacy, but rather to a large increase in mitochondrial respiration supported primarily by the non‐phosphorylating alternative oxidative pathway (AOP) and, to a lesser degree, the cytochrome oxidative pathway (COP). The increase in respiration and AOP capacity in cold‐grown plants likely protects against reactive oxygen species (ROS) in mitochondria and photodamage in chloroplasts by consuming excess reductant via the alternative mitochondrial respiratory electron transport chain. |
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Keywords: | Salsola divaricata alternative oxidase pathway C3– C4 photosynthesis |
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