Haruki Kimura, Mimi Hashimoto-Sugimoto, Koh Iba, Ichiro Terashima and Wataru Yamori*


It has been reported that stomatal conductance often limits the steady-state photosynthetic rate. On the other hand, the stomatal limitation of photosynthesis in fluctuating light remains largely unknown, although, in nature, light fluctuates due to the changes in sun position, cloud cover and the overshadowing canopy. In this study, we analyzed three mutant lines of Arabidopsis thaliana with increased stomatal conductance, to examine to what extent stomatal opening limits photosynthesis in fluctuating light. The slac1 (slow anion channel-associated 1) and ost1 (open stomata 1) mutants with stay-open stomata, and the PATROL1 (proton ATPase translocation control 1) overexpression line with faster stomatal opening responses exhibited higher photosynthetic rates and plant growth in fluctuating light than the wild-type, whereas these four lines showed similar photosynthetic rates and plant growth in constant light. The slac1 and ost1 mutants tended to keep their stomata open in fluctuating light, resulting in lower water-use efficiency (WUE) than the wild-type. However, the PATROL1 overexpression line closed stomata when needed and opened stomata immediately upon irradiation, resulting in similar WUE to the wild-type. The present study clearly showed that there is room to optimize stomatal responses, leading to greater photosynthesis and biomass accumulation in fluctuating light in nature.

Paper Information

: Journal of Experimental Botany
: 10.1105/tpc.19.00532