Beauty and Sex: Flowering. Flowers are derived from the process of transition from vegetative to...

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Transcript of Beauty and Sex: Flowering. Flowers are derived from the process of transition from vegetative to...

  • Slide 1
  • Beauty and Sex: Flowering
  • Slide 2
  • Flowers are derived from the process of transition from vegetative to generative meristems
  • Slide 3
  • Primary and secondary inflorescences
  • Slide 4
  • Vegetative and generative meristems Sepals Petals Stamens Carpels Leaves SAM Vegetative meristemGenerative meristem FM
  • Slide 5
  • Floral organs are initiated from the floral meristem in concentric whorls Meristem identity genes floral organ identity genes cadastral genes
  • Slide 6
  • Floral organ identity genes are responsible for reproductive organ formation No sepals/petals No petals/stamens No stamens/pistils
  • Slide 7
  • Flowering is regulated by internal and external stimuli Juvenile to adult phase transition is characterized by morphological and physiological characteristics English Ivy (Hedera helix)
  • Slide 8
  • Juvenile to adult transition requires competence (adult vegetative phase), determination and expression
  • Slide 9
  • Photoperiodism is an external stimulus of flowering Short-day, long-day and day-neutral plants Night break inhibits floweringNight break of sufficient duration induces flowering
  • Slide 10
  • Photoperiodism is an external stimulus of flowering
  • Slide 11
  • Plants are adapted to day-length at different latitudes Phytochromes and cryptochromes are the photoreceptors that regulate flowering West Lafayette
  • Slide 12
  • Natural variation in Arabidopsis GermanyWest-Africa
  • Slide 13
  • Plants are adapted to day-length at different latitudes Phytochromes and cryptochromes are the photoreceptors that regulate flowering Ler Cvi Ler Cvi
  • Slide 14
  • Plants track time with their circadian clock Periodic rhythm of plant processes that is regulated by an internal timepiece
  • Slide 15
  • CO (CONSTANS) and FT (FLOWERING LOCUS T ) are regulators of flowering in Arabidopsis (long-day plants) CO expression is clock controlled CO protein accumulation is regulated by proteolysis
  • Slide 16
  • Similar homologs Regulate flowering in short-day plants Rice (short-day plant) - Heading-date1 (Hd1) = CO and Heading-date3 (Hd3) = FT However, Hd1 inhibits Hd3 activation of flowering
  • Slide 17
  • Vernalization is required before some plants are responsive to photoperiodic-induced floral transition FLC negatively regulates flowering
  • Slide 18
  • Vernalization is required before some plants are responsive to photoperiodic-induced floral transition FLC negatively regulates flowering
  • Slide 19
  • Plant Biology (2010) Smith et al. Florigen is the biochemical signal for flowering
  • Slide 20
  • Zeevart (2007) Taiz and Zeiger Web Essay 25.2 FLOWERING LOCUS T
  • Slide 21
  • Plant Biology (2010) Smith et al. Integration of flowering stimuli