Ontogeny, phylogeny and evolution of the vascular system of lianas

Abstract

One of the major goals of evolutionary developmental biology is to understand the processes involved in the generation of morphological diversity. One way to address this question is through ontogenetical comparison of the ontogeny of the species within a phylogenetic framework. In the present study, lianas belonging to three families: Celastraceae, Malpighiaceae and Sapindaceae were chosen for possessing a huge extent of anatomical diversity, generated by the present of cambial variants in their stems, and robust phylogenies recently published. Thus, a study of ontogeny and phylogeny aims to unravel the mechanisms involved on the diversification of the vascular system of lianas. We aim to describe the ontogeny of the cambial variants, how they evolved and the presence of evolutionary convergences in the development of their tissues. Collections will be made in natural populations, living collections or xylothecs. In addition, a global analysis of lianas involving species of other groups will be carried out to better understand the structural patter of the phloem in lianas, a part of the vascular system usually neglected, to search for convergences in their vascular system, something that has been extensively explored for the secondary xylem. Anatomical procedures will follow the standard techniques in plant anatomy; characters will be delimited according to their variation within the groups and subsequently will be mapped in the phylogenies to evaluate the evolutionary patterns acting in the diversification nowadays present in the vascular system of lianas. With this work we aim to better understand the evolution of the cambial variants and the secondary phloem of lianas as a whole. (AU)