The Basis of Expression of Leaf Photosynthetic Activities

Abstract

Since the leaf is a heterogeneous assemblage of tissues, only a part of which are photosynthetically active, the anatomy and structure of the leaf may affect its photosynthetic performance. In order to examine this problem a simple analysis has been made of the role of leaf structure in determining the rates of transfer of carbon dioxide from the air to the assimilatory sites within the leaf.

The analysis is supported by published experimental data. An investigation of leaf photosynthesis by Lycopersicon esculentum grown at three light levels suggests that despite large differences in the thickness of leaves from the different growth environments the rate of transfer of carbon dioxide from the air to the assimilatory sites was in no case a limiting factor to photosynthesis.

The basis of expression of leaf photosynthetic data is discussed in relation to the physiological and mathematical interpretation of the response of leaf photosynthesis to the plant growth environment.