title: Phylogeography and modes of reproduction in diploid and tetraploid halophytes of Limonium species (Plumbaginaceae): evidence for a pattern of geographical parthenogenesis.
abstract: OBJECTIVE
  The genus Limonium (Plumbaginaceae) has long been recognized to have sexual and apomictic (asexual seed formation) modes of reproduction. This study aimed to elucidate phylogeographical patterns and modes of reproduction in diploid and tetraploid Limonium species, namely three putative sexual diploid species with morphological affinities (L. nydeggeri, L. ovalifolium, L. lanceolatum) and three related, probably apomict tetraploid species (L. binervosum, L. dodartii, L. multiflorum).
  
  
  METHODS
  cpDNA diversity and differentiation between natural populations of the species were investigated using two chloroplast sequence regions (trnL intron and trnL-trnF intergenic spacer). Floral heteromorphies, ovule cytoembryological analyses and pollination and crossing tests were performed in representative species of each ploidy group, namely diploid L. ovalifolium and tetraploid L. multiflorum, using plants from greenhouse collections.
  
  
  CONCLUSIONS
  Genetic analyses showed that diploid species have a higher haplotype diversity and a higher number of unique (endemic) haplotypes than tetraploid species. Network analysis revealed correlations between cpDNA haplotype distribution and ploidy groups, species groups and geographical origin, and haplotype sharing within and among species with distinct ploidy levels. Reproductive biology analyses showed that diploid L. ovalifolium mainly forms meiotically reduced tetrasporic embryo sacs of Gagea ova, Adoxa and Drusa types. Limonium multiflorum, however, has only unreduced, diplosporic (apomictic) embryo sacs of Rudbeckia type, and autonomous apomictic development seems to occur. Taken together, the findings provide evidence of a pattern of 'geographical parthenogenesis' in which quaternary climatic oscillations appear to be involved in the geographical patterns of coastal diploid and tetraploid Limonium species.
authors.affiliation: Centro de Investigação em Agronomia, Alimentos, Ambiente e Paisagem (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Róis
authors.affiliation: Centro de Investigação em Agronomia, Alimentos, Ambiente e Paisagem (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal.
authors.forename: Flávio
authors.initials: F
authors.lastname: Sádio
authors.affiliation: cE3c - Centre for Ecology Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa (ULisboa), Campo Grande, 1649-003 Lisboa, Portugal.
authors.forename: Octávio S
authors.initials: OS
authors.lastname: Paulo
authors.affiliation: cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Farmácia, Universidade de Lisboa (ULisboa), Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal.
authors.forename: Generosa
authors.initials: G
authors.lastname: Teixeira
authors.affiliation: Centro de Investigação em Agronomia, Alimentos, Ambiente e Paisagem (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Paes
authors.affiliation: Centro de Investigação em Agronomia, Alimentos, Ambiente e Paisagem (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal, Research Network in Biodiversity and Evolutionary Biology (InBIO), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal and.
authors.forename: Dalila
authors.initials: D
authors.lastname: Espírito-Santo
authors.affiliation: Apomixis Research Group, Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Sharbel
authors.affiliation: Centro de Investigação em Agronomia, Alimentos, Ambiente e Paisagem (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal, Research Network in Biodiversity and Evolutionary Biology (InBIO), Instituto Superior de Agronomia (ISA), Universidade de Lisboa (ULisboa), Tapada da Ajuda, 1349-017 Lisboa, Portugal and anadelaunay@isa.ulisboa.pt.
authors.forename: Ana D
authors.initials: AD
authors.lastname: Caperta
mesh_terms: D018742:DNA, Chloroplast / Q000235:genetics; D004171:Diploidy; D014644:Genetic Variation; D056771:Ovule / Q000254:growth & development; D010312:Parthenogenesis; D058974:Phylogeography; D029606:Plumbaginaceae / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D011058:Pollen / Q000648:ultrastructure; D011174:Portugal; D012098:Reproduction; D055051:Salt-Tolerant Plants / Q000502:physiology* / Q000648:ultrastructure; D012639:Seeds / Q000648:ultrastructure; D057891:Tetraploidy
chemical_list: D018742:DNA, Chloroplast
keywords: Apomixis; Limonium; cpDNA; cytoplasmic markers; female gametophyte development; floral biology; geographical parthenogenesis; phylogeography; polyploidy; reproductive modes