The birds and the bees…
Mating systems in plants
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Sexual vs. asexual reproduction
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Outbreeding •
When inbreeding is good
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Pollination syndromes
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Asexual reproduction
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Importance of mating system information to conservation Sexual vs. Asexual Reproduction Sexual – union of egg and sperm
1) Outcrossing – two dissimilar individuals 2) Inbreeding – two similar individuals Autogamy Biparental inbreeding (= geitonogamy)
Asexual – identical (nearly so) copy of the parent
1) Vegetative – rhizomes, stolons, buds, fragmentation
2) Agamospermy (= apomixis)
Mechanisms to promote outbreeding Temporal differences in maturity of stamens and carpels
1. female phase
Asimina triloba
Mechanisms to promote outbreeding Physical separation of stamens & carpels
Heterostyly
Mechanisms to promote outbreeding Physical separation of stamens & carpels
Unisexual flowers
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Dimorphic breeding systems include: Monoecy – separate male and female flowers
Dioecy – separate male and female plants (6%)
Gynodioecy – separate females and hermaphrodites
Androdioecy – males and hermaphrodites (rare)
Sex changes
Lindera melissifolia
Arisaema triphyllum
How do plants promote outbreeding? Gametophytic incompatibility How do plants promote outbreeding? Sporophytic incompatibility None
Inbreeding
When is it beneficial?
Obligate autogamy
Facultative autogamy
Inbreeding through geitonogamy
Animal pollinators are needed for reproduction of ~90% of Angiosperms
Pollination syndrome = a suite of traits hypothesized to reflect convergent adaptation of flowers for pollination by specific types of biotic or abiotic agents.
Forms of asexual reproduction
Vegetative reproduction Rhizome
Forms of asexual reproduction
Agamospermy (= apomixis)
Common in Asteraceae, Poaceae, Rosaceae
Two ways: 1) Parthenogenesis – egg differentiates in a megagametophyte and becomes an embryo
2) Adventitious embryony – embryo develops directly from somatic cell (Citrus)
Importance of mating systems to conservation genetics The mating system controls genetic diversity. Inbreeding, low reproduction  loss of diversity and genetic drift How do we determine the mating system? • Controlled crosses • Pollinator studies • Genetic data Number of multilocus genotypes
Comparison of Ho and He
Calculation of FIS
Paternity analyses