Between Xylem and Phloem: The Genetic Control of Cambial Activity in Plants

Abstract: Post-embryonic development is controlled by two types of meristems: apical and lateral. There has been considerable progress recently in understanding the function of root and shoot apical meristems at the molecular level. Knowledge of analogous processes in the lateral, or secondary, meristems, i.e. the vascular cambium or cork cambium, is, however, rudimentary. This is despite the fact that much of the diversity in the plant kingdom is based on the differential functions of these meristems, emphasizing the importance of lateral meristems in the development of different plant forms. The vascular cambium is particularly important for woody plants, but it also plays an important role during the development of various herbaceous species, such as Arabidopsis thaliana. In this review, we focus on the two basic functions of cambial activity: cell proliferation and pattern formation.