Daily Variations of Stem and Branch Diameter: Short Overview from a Developed Example

Abstract

Reversible and irreversible changes in size of plant tissues have been observed for almost a century. Reversible changes are accounted for by changing degrees of hydration, while irreversible changes, often superposed on the previous ones, result from continuous growth of tissues through cell division and enlargement. During the last decade many attempts have been made to use the variations of stem and fruit to schedule irrigation, especially in orchards where more traditional methods are difficult to apply. The major advantage of this “micromorphometric” approach is that changes in diameter are a very sensitive indicator of the plant response to water supply conditions, more than the others usually employed (like leaf water potential), and can be recorded continuously. However much work should be done to achieve a precise interpretation of these variations of diameter. Supported by an example taken in our current research, this paper gives a rapid overview of some typical results and open questions in this domain.