Principles of Gas Exchange in Bulky Plant Tissues

Determination of diffusivity of gases in bulky plant tissues is of both theoretical and practical interest. For instance, a precise knowledge of O 2 diffusion is needed for studying the nature of “oxidases” that may be involved in fruit respiration and also for predicting minimum O 2 levels that can be safely used in controlled atmosphere (CA) storage. Further, a precise knowledge of the internal concentration of ethylene may be useful in determining the maturity of apples before harvest (15). Principles and techniques used for determining resistance to gas diffusion in bulky plant organs, and some practical applications for CA storage of apples are presented here.