Phylogeny of rutaceae and revision of Hortia Vand

Author(s)

Milton Groppo Junior

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2004-11-17

Examining board members

Jose Rubens Pirani; Antonio Carlos Marques; Lucia Rossi; Kikyo Yamamoto

• Advisor: Jose Rubens Pirani

Abstract

This work consisted in a revision and a palynological study of Hortia Vand., besides a phylogenetic analysis of Rutaceae based on data from two non-coding regions of the chloroplast genome. It is divided in three chapters: 1) A revision of Hortia Vand. A taxonomic revision of the genus Hortia(Rutaceae) is presented. Hortia is a neotropical taxon, most of the species occur in the Amazonian region. The species are woody, almost all trees, with simple leaves crowded near the apices of the branches, showy broad corymbose terminal inflorescences, reddish to pink flowers, and baccate fruits with abundant oils glands. Ten species are recognized here, most of them occurring in Brazil. Key to the species, descriptions, synonyms, illustrations, as well as comments on the geographic distribution, ecology and economic uses of each species are presented. 2) Palynological morphology in species of Hortia (Rutaceae). A palynological study covering all 10 species of the neotropical genus Hortia Vand. (Rutaceae) was made. The analysis confirmed previous findings that the genus is estenopalynous, with subprolate to prolate, 3-colporate grains, with a very thick exine and a psilate-perforate pattern of sculpturing. Even though the genus is well characterized palynologically, the pollen of all species are very similar, with little variation in the sculpture of exine, number and form of apertures and measurements. Pollen characteres were also uninformative in relation to the positioning of Hortia into an intrafamilial classification. 3) Phylogeny and classification of Rutaceae based on two non-coding regions of the cpDNA. A phylogenetic analysis of Rutaceae, including representatives of all subfamilies, tribes and most subtribes (59 genera and 65 species, representing more than 1/3 of the genera in the family) was conducted. This analysis used DNA sequence data from two non-coding regions of the chloroplast genome, the rps-16 intron and the trnL-trnF region. This study included a larger sampling from the subfamily Toddalioideae and from Neotropical groups than previous studies. Consensus trees from both separated and combined analyses are congruent and consistent with results found in previous rbcL and aptB studies. This phylogeny confirmed that Simaroubaceae and Meliaceae are the closest families to Rutaceae, as well as that Cneorum, Ptaeroxylon, Spathelia and Dictyoloma form a basal clade that is sister to the remaining Rutaceae. With the exception of Aurantioideae, none of the subfamilies with more than one genus is monophyletic. Characters of the gynoeceum, fruit, seeds and embryo are not of reliable for the circumscription of subfamilies. As a consequence, the tradicional subfamilial classification of the family is revised, and only two subfamilies are recognized: Rutoideae and Spathelioideae. Even though Aurantioideae is monophyletic, this was reduced to a tribal rank (Aurantieae) and included in Rutoideae in the light of the position of Ruta. Additionally, the circumscription of tribes and some subtribes within Rutoideae will also need to be reevaluated. The results are discussed in the light of the distribution of the various groups studied, and in the light of the fossil record, caryology, quimiotaxonomy and other available molecular data. (AU)