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