Plant Biol (Stuttg) 2005; 7(5): 533-540
DOI: 10.1055/s-2005-865852
Research Paper

Georg Thieme Verlag Stuttgart KG · New York

Polyembryony and Apomixis in Eriotheca pubescens (Malvaceae - Bombacoideae)

C. Mendes-Rodrigues1 , R. Carmo-Oliveira1 , S. Talavera2 , M. Arista2 , P. L. Ortiz2 , P. E. Oliveira1
  • 1Instituto de Biologia, Universidade Federal de Uberlândia, Caixa Postal 593, Uberlândia-MG, CEP 38400-902, Brazil
  • 2Departamento de Biología Vegetal y Ecologia, Universidad de Sevilla, Apdo. 1095, 41080 Sevilla, Spain
Weitere Informationen

Publikationsverlauf

Received: March 14, 2005

Accepted: May 25, 2005

Publikationsdatum:
15. September 2005 (online)

Abstract

Apomixis and adventitious polyembryony have been reported for several species of Bombacoideae, including Eriotheca pubescens, a tree species of the Neotropical savanna (Cerrado) areas in Brazil. However, the origin of polyembryonic seeds and their importance for the reproduction of the species remained to be shown. Here, we analyzed the early embryology of this species to establish the apomictic origin of extranumerary embryos. We also observed the geographic distribution of polyembryony in E. pubescens, and tested if apomixis was related to the source of pollen (self or cross) and population density. Moreover, we tested if polyembryonic apomictic embryos would develop normally into seedlings. In the observed seed primordia, after a relatively long quiescent period, the zygote developed into a sexual embryo concurrently with adventitious apomictic embryos which developed from nucellus cells. Adventitious embryos develop faster than sexual ones and are morphologically similar, so that 44 days after anthesis it was virtually impossible to distinguish and trace the fate of the sexual embryo. Polyembryony is widely distributed in populations some 400 km distant, and only one strictly monoembryonic individual was observed during the study. The number of embryos per seed varied between fruits and individuals but was significantly higher in seeds from cross-pollinations than from selfs, although fruit and seed set after crosses were much lower than after selfs. Embryo development into seedlings depended on their weight at germination, but polyembryonic seeds germinated and produced up to seven seedlings per seed in greenhouse conditions. Adventitious embryony and apomictic seedlings would explain the mostly clonal populations suggested by molecular studies.

References

P. E. Oliveira

Instituto de Biologia
Universidade Federal de Uberlândia

Caixa Postal 593

Uberlândia-MG, CEP 38400-902

Brazil

eMail: poliveira@ufu.br

Editor: S. S. Renner

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