EVOLUTION OF NOVEL MORPHOLOGICAL AND REPRODUCTIVE TRAITS IN A CLADE CONTAINING ANTIRRHINUM-MAJUS (SCROPHULARIACEAE)

Citation
Pa. Reeves et Rg. Olmstead, EVOLUTION OF NOVEL MORPHOLOGICAL AND REPRODUCTIVE TRAITS IN A CLADE CONTAINING ANTIRRHINUM-MAJUS (SCROPHULARIACEAE), American journal of botany, 85(8), 1998, pp. 1047-1056
Citations number
81
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
0002-9122
Volume
85
Issue
8
Year of publication
1998
Pages
1047 - 1056
Database
ISI
SICI code
0002-9122(1998)85:8<1047:EONMAR>2.0.ZU;2-T
Abstract
Phylogenetic analysis of DNA sequences of the chloroplast genes rbcL a nd ndhF revealed a highly supported clade composed of the families Pla ntaginaceae, Callitrichaceae, and Hippuridaceae in close association w ith the model organism Antirrhinum majus and other members of family S crophulariaceae. Plantago has miniature actinomorphic wind-pollinated flowers that have evolved from zygomorphic animal-pollinated precursor s. The aquatic Hippuridaceae have reduced wind-pollinated flowers with one reproductive organ per whorl, and three, rather than four whorls. In monoecious aquatic Callitrichaceae, further reduction has occurred such that there is only one whorl per flower containing a single stam en or carpel. Optimization of character states showed that these famil ies descended from an ancestor similar to Antirrhinum majus. Recent st udies of plant developmental genetics have focused on distantly relate d species. Differences in the molecular mechanisms controlling floral development between model organisms are difficult ro interpret due to phylogenetic distance. In order to understand evolutionary changes in floral morphology in terms of their underlying genetic processes, clos ely related species exhibiting morphological variation should be exami ned. Studies of genes that regulate morphogenesis in the clade describ ed here could aid in the elucidation of a general model for such funda mental issues as how changes in floral symmetry, organ number, and who rl number are achieved, as well as providing insight on the evolution of dicliny and associated changes in pollination syndrome.