title: Pollen flow and effects of population structure on selfing rates and female and male reproductive success in fragmented Magnolia stellata populations.
abstract: BACKGROUND
  Fragmentation of plant populations may affect mating patterns and female and male reproductive success. To improve understanding of fragmentation effects on plant reproduction, we investigated the pollen flow patterns in six adjacent local populations of Magnolia stellata, an insect-pollinated, threatened tree species in Japan, and assessed effects of maternal plant (genet) size, local genet density, population size and neighboring population size on female reproductive success (seed production rates), and effects of mating distance, paternal genet size, population size and separation of populations on male reproductive success.
  
  
  RESULTS
  The seed production rate, i.e. the proportion of ovules that successfully turned into seeds, varied between 1.0 and 6.5%, and increased with increasing population size and neighboring population size, and with decreasing maternal genet size and local genet density. The selfing rate varied between 3.6 and 28.9%, and increased with increasing maternal genet size and with declining local genet density. Male reproductive success increased with increasing paternal genet size, and decreased with increasing mating distance and separation of population. Pollen flow between the populations was low (6.1%) and highly leptocurtic.
  
  
  CONCLUSIONS
  Our results indicate that habitat fragmentation, separation and reduced size of populations, affected mating patterns and reproductive success of M. stellata. Local competition for pollinators and plant display size were likely to alter the reproductive success.
authors.affiliation: Department of Forest Genetics, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan. setsukos@affrc.go.jp
authors.forename: Suzuki
authors.initials: S
authors.lastname: Setsuko
authors.forename: Teruyoshi
authors.initials: T
authors.lastname: Nagamitsu
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tomaru
mesh_terms: D000818:Animals; D055993:Germ Cells, Plant / Q000737:chemistry / Q000254:growth & development*; D007700:Kinetics; D031566:Magnolia / Q000737:chemistry / Q000254:growth & development* / Q000502:physiology; D011058:Pollen / Q000737:chemistry / Q000254:growth & development* / Q000502:physiology; D012098:Reproduction