Pulsations of domain length as support for the hypothesis of morphogenetic waves in the cambium

Abstract

The domains in the cambium may be of different length and each domain varies then in length cyclically with time. Such pulsating domain patterns have been described in <i>Fraxinus</i>. A common basis to understand the different aspects of domain pattern - the arrangement of domains, reversals of domain type at a particular site, and the pulsation of domain length - is offered by the hypothesis that there are waves of orientational tendencies in the cambium. The domain pattern itself would represent the spatial aspect of the wave, the reversals of domain type at a particular site in the cambium would represent the time aspect of the wave, while the pulsation of domain length would be due to superposition of waves which differ in length and velocity.