AUTHOR=Kang Huixing , Zhu Ting , Zhang Yan , Ke Xinran , Sun Wenjuan , Hu Zhenghua , Zhu Xinguang , Shen Haihua , Huang Yao , Tang Yanhong 

TITLE=Elevated CO2 Enhances Dynamic Photosynthesis in Rice and Wheat

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.727374

DOI=10.3389/fpls.2021.727374

ISSN=1664-462X

ABSTRACT=<p>Crops developed under elevated carbon dioxide (eCO<sub>2</sub>) exhibit enhanced leaf photosynthesis under steady states. However, little is known about the effect of eCO<sub>2</sub> on dynamic photosynthesis and the relative contribution of the short-term (substrate) and long-term (acclimation) effects of eCO<sub>2</sub>. We grew an <italic>Oryza sativa japonica</italic> cultivar and a <italic>Triticum aestivum</italic> cultivar under 400 μmol CO<sub>2</sub> mol<sup>−1</sup> air (ambient, <italic>A</italic>) and 600 μmol CO<sub>2</sub> mol<sup>−1</sup> air (elevated, <italic>E</italic>). Regardless of growth [CO<sub>2</sub>], the photosynthetic responses to the sudden increase and decrease in light intensity were characterized under 400 (<italic>a</italic>) or 600 μmol CO<sub>2</sub> mol<sup>−1</sup> air (<italic>e</italic>). The <italic>Aa</italic><xref ref-type="fn" rid="fn0001"><sup>1</sup></xref>, <italic>Ae</italic><xref ref-type="fn" rid="fn0002"><sup>2</sup></xref>, <italic>Ea</italic><xref ref-type="fn" rid="fn0003"><sup>3</sup></xref>, and <italic>Ee</italic><xref ref-type="fn" rid="fn0004"><sup>4</sup></xref> treatments were employed to quantify the acclimation effect (<italic>Ae</italic> vs. <italic>Ee</italic> and <italic>Aa</italic> vs. <italic>Ea</italic>) and substrate effect (<italic>Aa</italic> vs. <italic>Ae</italic> and <italic>Ea</italic> vs. <italic>Ee</italic>). In comparison with the <italic>Aa</italic> treatment, both the steady-state photosynthetic rate (<italic>P</italic><sub>N</sub>) and induction state (IS) were higher under the <italic>Ae</italic> and <italic>Ee</italic> treatments but lower under the <italic>Ea</italic> treatment in both species. However, IS reached at the 60 sec after the increase in light intensity, the time required for photosynthetic induction, and induction efficiency under <italic>Ae</italic> and <italic>Ee</italic> treatment did not differ significantly from those under <italic>Aa</italic> treatment. The substrate effect increased the accumulative carbon gain (ACG) during photosynthetic induction by 45.5% in rice and by 39.3% in wheat, whereas the acclimation effect decreased the ACG by 18.3% in rice but increased it by 7.5% in wheat. Thus, eCO<sub>2</sub>, either during growth or at measurement, enhances the dynamic photosynthetic carbon gain in both crop species. This indicates that photosynthetic carbon loss due to an induction limitation may be reduced in the future, under a high-CO<sub>2</sub> world.</p>