PHOTOSYNTHESIS IN RELATION TO STOMATAL FREQUENCY AND DISTRIBUTION

Abstract

Apparent photosynthesis, in terms of mg. of CO2 used, was detd. for the upper and lower surfaces of leaves. Plants were chosen for the study with stomates in the lower epidermis alone as Coleus blumei, Persea americana, Euphorbia pulcherrima, Ficus elastica, Begonia sp., and Rhoea discolor; and with stomates in both the upper and lower epidermis as Phaseolus vulgaris, Nicotiana tabacum, and Pelargonium zonale. Results for the plants with stomates only in the lower epidermis indicate that the amt. of CO2 diffusing through the epidermis alone may be as large as that passing through the stomates, except for some leaves with a thick cuticle. From the data for the plants having stomates in both surfaces of their leaves it is evident that the diffusion of CO2 into the leaves during photosynthesis may or may not show a direct correlation with stomatal frequency and distribution.