Abstract
This research was undertaken to explain why high stomatal frequency (low stomatal resistance) Ieaf had high photosynthetic capacity by gas diffusion theory. Mesophyll resistance was estimated by electrical analogues taking account of respiration during photosynthesis. The mesophyll resistance was estimated from the data of photosynthesis and transpiration in barley differing in stomatal frequency or stomatal resistance. The assumptions were that C02 concentration in the atmosphere, C02 concentration at the chloroplasts and mesophyll resistance were constant. The results showed that mesophyll resistance was much smaller than was reported previously and stomatal resistance had an important role in controlling photosynthesis.
