Water Vapour and Carbon Dioxide Diffusion Resistances of FourHevea brasiliensisClonal Seedlings

SUMMARY Differences in the net photosynthetic rates of two classes of Hevea clonal seedlings are explained in terms of resistances to carbon dioxide diffusion from the outside air into the carboxylation sites. The residual resistance, the sum of the mesophyll and the carboxylation resistances, is apparently related to photosynthetic rates.