Flow and Transport in Plants

This review is not a discussion in the language of fluid mechanics about esoteric proper ties of flow in plants, but an attempt by a botanist to explain, with as little technical botanical language as possible, how the life and construction of plants raise problems of flow, some of which are still unresolved. In order to understand these problems it will be necessary to become acquainted with some of the details of plant construction (morphology, anatomy), and some of the conditions of plant life (physiology). At several places in the explanation I have felt that the special knowledge of readers of this Review might illuminate matters that are still obscure to botanists. The symbol (t) indicates such calls for help. Ref erences are scarcely quoted since they are written in a technical jargon that would be barely understood. Rather the names are given of a few works that may serve as entry points into the li terature for any reader who wishes to follow particular lines of thought, and these are grouped in a Bibliography with an indication of their scope. Calculations by plant physiologists about the flows to he discussed are always done in terms of Poiseuille's equation. We are not sensitive to the limitations of this approach or aware of other relations that might be more appropriate in the fluid spaces of the plant (t). Technical botanical terms are italicized at their first appearance.