The need to re-investigate the nature of homoplastic characters: an ontogenetic case study of the 'bracteoles' in Atripliceae (Chenopodiaceae)
Por:
Flores-Olvera H., Vrijdaghs A., Ochoterena H., Smets E.
Publicada:
1 oct 2011
Categoría:
Plant Science
Resumen:
Background and Aims Within Chenopodioideae, Atripliceae have been distinguished by two bracteoles enveloping the female flowers/fruits, whereas in other tribes flowers are described as ebracteolate with persistent perianth. Molecular phylogenetic hypotheses suggest 'bracteoles' to be homoplastic. The origin of the bracteoles was explained by successive inflorescence reductions. Flower reduction was used to explain sex determination. Therefore, floral ontogeny was studied to evaluate the nature of the bracteoles and sex determination in Atripliceae. Methods Inflorescences of species of Atriplex, Chenopodium, Dysphania and Spinacia oleracea were investigated using light microscopy and scanning electron microscopy. Key Results The main axis of the inflorescence is indeterminate with elementary dichasia as lateral units. Flowers develop centripetally, with first the formation of a perianth primordium either from a ring primordium or from five individual tepal primordia fusing post-genitall
Filiaciones:
Flores-Olvera H.:
Univ Nacl Autonoma Mexico, Inst Biol, Dept Bot, Mexico City 04510, DF, Mexico
Vrijdaghs A.:
Laboratory of Plant Systematics, KU Leuven, Belgium
Ochoterena H.:
Univ Nacl Autonoma Mexico, Inst Biol, Dept Bot, Mexico City 04510, DF, Mexico
Smets E.:
Laboratory of Plant Systematics, KU Leuven, Belgium
National Herbarium of the Netherlands, Leiden University Branch, Netherlands
All Open Access, Bronze
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