Fig. 9. Relationship between the rate of gross photosynthesis and the total pressure
under high- or low-absolute-humidity. The rates of gross photosynthesis were
analyzed from the results of respiration (Fig. 6) and net photosynthesis (Fig. 8). The
results indicate that absolute humidity has an effect on gross photosynthesis. Under
high humidity, the rates of gross photosynthesis were equal to that at 0.1 MPa. Under
low humidity, the rate of gross photosynthesis increased slightly up to 1.7 times with
increasing total pressure.