Ikawa, Hiroki Sakai, Hidemitsu Chen, Charles P. Soong, Tik Hang Yonemura, Seiichiro Taniguchi, Yojiro Yoshimoto, Mayumi Tokida, Takeshi Zhang, Guoyou Kuwagata, Tsuneo Nakamura, Hirofumi Avenson, Tom Hasegawa, Toshihiro High mesophyll conductance in the high-yielding rice cultivar Takanari quantified with the combined gas exchange and chlorophyll fluorescence measurements under free-air CO<sub>2</sub> enrichment <p>An effective strategy for increasing crop production is increasing the rate of photosynthesis. In this study, we conducted gas exchange and chlorophyll fluorescence measurements for a high-yielding rice cultivar, Takanari, to identify the leaf physiological properties that contribute to high capacity for photosynthesis of the uppermost leaves before (panicle initiation stage) and after heading (grain-filling stage) in the Tsukuba free-air CO<sub>2</sub> enrichment (FACE) facility. The higher photosynthesis rate of Takanari compared with that of the commonly cultivated cultivar, Koshihikari, was mainly attributed to the greater stomatal conductance for CO<sub>2</sub> (<i>g<sub>sc</sub></i>) at the panicle initiation stage and to the greater mesophyll conductance (<i>g<sub>m</sub></i>) at the grain-filling stage in both current and elevated atmospheric CO<sub>2</sub> concentrations [CO<sub>2</sub>]. Takanari had a higher level of leaf nitrogen content (<i>N<sub>l</sub></i>) compared with Koshihikari at the grain-filling stage, which led to greater <i>g<sub>m</sub></i> and maximum carboxylation rate (<i>V<sub>c,</sub></i><sub>max</sub>), but <i>N<sub>l</sub></i> alone did not explain the variations of <i>g<sub>m</sub></i> within the variety. A clear correlation was found between <i>V<sub>c,</sub></i><sub>max</sub> and <i>N<sub>l</sub></i>. Calculating <i>V<sub>c,</sub></i><sub>max</sub> taking <i>g<sub>m</sub></i> into consideration removed the artifact of <i>V<sub>c,</sub></i><sub>max</sub><i><sub>25</sub></i> in relation to <i>N<sub>l</sub></i> that was observed when <i>g<sub>m</sub></i> was assumed to be infinite. Our results emphasize the need to separate the roles of <i>V<sub>c,</sub></i><sub>max</sub> and <i>g<sub>m</sub></i> to accurately understand the ecophysiological processes that control leaf photosynthesis in Takanari.</p> Takanari;free-air CO2 enrichment;photosynthesis;maximum carboxylation rate;mesophyll conductance;stomatal conductance;leaf nitrogen content 2019-07-10
    https://tandf.figshare.com/articles/journal_contribution/High_mesophyll_conductance_in_the_high-yielding_rice_cultivar_Takanari_quantified_with_the_combined_gas_exchange_and_chlorophyll_fluorescence_measurements_under_free-air_CO_sub_2_sub_enrichment/8850095
10.6084/m9.figshare.8850095.v1