Fig. 1

The averages of photosynthetic rate (A; μmol m^–2 s^–1), transpiration rate (E; mmol m^–2 s^–1), stomatal conductance (gs; mol m^–2 s^–1), substomatal CO₂ partial pressure (Ci; vpm), photosynthetic rate (A/Ci) per substomatal CO₂ partial pressure, and water use efficiency (WUE; μmol CO₂/mmol H₂O) on 54 replications per duty ratio condition within 20 Hz, 60 Hz, 180 Hz, 540 Hz, 1620 Hz, and 4860 Hz of light frequency. The error bars and letters on the bars refer to the sample standard deviations and significant differences among the duty ratio groups, respectively. A graph without the letters on the bars means that there are no significant differences among the duty ratio groups