The acclimation of photosynthesis and respiration to temperature in the C3 -C4 intermediate Salsola divaricata: induction of high respiratory CO2 release under low temperature.
Photosynthesis in C(3) -C(4) intermediates reduces carbon loss by photorespiration through refixing photorespired CO(2) within bundle sheath cells. This is beneficial under warm temperatures where rates of photorespiration are high; however, it is unknown how photosynthesis in C(3) -C(4) plants acclimates to growth under cold conditions. Therefore, the cold tolerance of the C(3) -C(4) Salsola divaricata was tested to determine whether it reverts to C(3) 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 C(3) -C(4) features acclimate to these growth conditions. The CO(2) compensation point and net rates of CO(2) assimilation in cold-grown plants changed dramatically when measured in response to temperature. However, this was not due to the loss of C(3) -C(4) 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.
School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA.
Anthony
A
Gandin
Nuria K
NK
Koteyeva
Elena V
EV
Voznesenskaya
Gerald E
GE
Edwards
Asaph B
AB
Cousins
D000064:Acclimatization / Q000502:physiology*; D015153:Blotting, Western; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D019069:Cell Respiration; D003080:Cold Temperature; D003580:Cytochromes / Q000378:metabolism; D050841:Glycine Dehydrogenase (Decarboxylating) / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000166:cytology / Q000648:ultrastructure; D010940:Plant Proteins / Q000378:metabolism; D031248:Salsola / Q000166:cytology / Q000201:enzymology / Q000502:physiology* / Q000648:ultrastructure; D000099188:Alternative Oxidase
D002244:Carbon; D002245:Carbon Dioxide; D003580:Cytochromes; D050841:Glycine Dehydrogenase (Decarboxylating); D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D000099188:Alternative Oxidase
C3-C4 photosynthesis; Salsola divaricata; alternative oxidase pathway