シロイヌナズナ葉の葉緑体配置がCO₂コンダクタンスに及ぼす影響

抄録

Photosynthesis is affected by the conductance of CO₂ from the atmosphere to the site of carboxylation. The location of chloroplasts in the mesophyll cells may affect the length of the diffusion pathway for CO₂. Using different light treatments to induce chloroplast movements we studied the effect of chloroplast location on a number of photosynthetic parameters in Arabidopsis thaliana. In addition, we examined these parameters in mutants which do not show a chloroplast avoidance response under high light conditions. Furthermore, we investigated the internal conductance after externally applying an inhibitor of chloroplast movement. Following gas-exchange measurements we sampled the leaves for anatomical measurements to quantify the length of the diffusion pathways. Our results indicate that chloroplast movement affects internal conductance for CO₂, and this in turn exerts a small effect on the photosynthetic capacity in A. thaliana.