Plant carbon metabolism and climate change: elevated <scp>CO</scp>₂ and temperature impacts on photosynthesis, photorespiration and respiration

<jats:sec><jats:label /><jats:p> <jats:table-wrap position="anchor"> <jats:table frame="hsides"> <jats:col /> <jats:col /> <jats:col /> <jats:thead> <jats:tr> <jats:th>Contents</jats:th> </jats:tr> </jats:thead> <jats:tbody> <jats:tr> <jats:td /> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-1001">Summary</jats:ext-link></jats:td> <jats:td>32</jats:td> </jats:tr> <jats:tr> <jats:td>I.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0002">The importance of plant carbon metabolism for climate change</jats:ext-link></jats:td> <jats:td>32</jats:td> </jats:tr> <jats:tr> <jats:td>II.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0003">Rising atmospheric CO2 and carbon metabolism</jats:ext-link></jats:td> <jats:td>33</jats:td> </jats:tr> <jats:tr> <jats:td>III.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0004">Rising temperatures and carbon metabolism</jats:ext-link></jats:td> <jats:td>37</jats:td> </jats:tr> <jats:tr> <jats:td>IV.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0005">Thermal acclimation responses of carbon metabolic processes can be best understood when studied together</jats:ext-link></jats:td> <jats:td>38</jats:td> </jats:tr> <jats:tr> <jats:td>V.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0006">Will elevated CO2 offset warming‐induced changes in carbon metabolism?</jats:ext-link></jats:td> <jats:td>40</jats:td> </jats:tr> <jats:tr> <jats:td>VI.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0007">No plant is an island: water and nutrient limitations define plant responses to climate drivers</jats:ext-link></jats:td> <jats:td>41</jats:td> </jats:tr> <jats:tr> <jats:td>VII.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0008">Conclusions</jats:ext-link></jats:td> <jats:td>42</jats:td> </jats:tr> <jats:tr> <jats:td /> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-sec-0009">Acknowledgements</jats:ext-link></jats:td> <jats:td>42</jats:td> </jats:tr> <jats:tr> <jats:td /> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-bibl-0001">References</jats:ext-link></jats:td> <jats:td>42</jats:td> </jats:tr> <jats:tr> <jats:td /> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#nph15283-app-0001">Appendix A1</jats:ext-link></jats:td> <jats:td>48</jats:td> </jats:tr> </jats:tbody> </jats:table> </jats:table-wrap> </jats:p></jats:sec><jats:sec><jats:title>Summary</jats:title><jats:p>Plant carbon metabolism is impacted by rising <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub> concentrations and temperatures, but also feeds back onto the climate system to help determine the trajectory of future climate change. Here we review how photosynthesis, photorespiration and respiration are affected by increasing atmospheric <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub> concentrations and climate warming, both separately and in combination. We also compile data from the literature on plants grown at multiple temperatures, focusing on net <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub> assimilation rates and leaf dark respiration rates measured at the growth temperature (<jats:italic>A</jats:italic><jats:sub>growth</jats:sub> and <jats:italic>R</jats:italic><jats:sub>growth</jats:sub>, respectively). Our analyses show that the ratio of <jats:italic>A</jats:italic><jats:sub>growth</jats:sub> to <jats:italic>R</jats:italic><jats:sub>growth</jats:sub> is generally homeostatic across a wide range of species and growth temperatures, and that species that have reduced <jats:italic>A</jats:italic><jats:sub>growth</jats:sub> at higher growth temperatures also tend to have reduced <jats:italic>R</jats:italic><jats:sub>growth</jats:sub>, while species that show stimulations in <jats:italic>A</jats:italic><jats:sub>growth</jats:sub> under warming tend to have higher <jats:italic>R</jats:italic><jats:sub>growth</jats:sub> in the hotter environment. These results highlight the need to study these physiological processes together to better predict how vegetation carbon metabolism will respond to climate change.</jats:p></jats:sec>