Figs 10 and 11 show comparisons of the rate of net photosynthesis
between the conditions of elevated total pressure and elevated
partial pressure of CO2 at low and high absolute humidities, respectively.
The results showed that, under both conditions, the rate of
net photosynthesis increased with increasing partial pressure of
CO2 at high absolute humidity. The rate of net photosynthesis under
elevated total pressure was equal to the rate of net photosynthesis
under the increased partial pressure of CO2 at 0.2 MPa. Under a total
pressure higher than 0.2 MPa, the rate of net photosynthesis was
lower than that under the increased partial pressure of CO2. On the
other hand, the rate of net photosynthesis under the elevated total
pressure was lower than that under the increased partial pressure
of CO2 at low absolute humidity.
Eq. (3) expresses the correlation among the rate of net photosynthesis,
stomatal conductance and CO2 concentration