Flowering Flashcards
What factors affect floral evocation?
- Day length
- Temperature
- Size
- Developmental state
- Stress
What is floral evoocation?
Plant is triggered to make reproductive tissue
What does SAM produce during vegetative growth, and then during floral evocation?
Vegetative growth: leaves and stem
Floral evocation: inflorescence and flowers
How many phytomers must tobacco variety wisconsin 38 produce before it flowers?
And what happens if the top is chopped off and rerooted before this number is achieved?
35
Delayed flowering
What is autonomous flowering?
Plant like Arabidopsis will flower after several months even in non-inductive conditions.
Due to size and age
What is vernalization?
Flowering induced by exposure to prolonged cold temperatures.
Where is vernalization sensed?
Meristem
What gene is involved in vernalization and what does it do?
FRIGIDA gene
represses flowering until plant has been exposed to low temps
What does vernalization involve changes in?
Involves changes in DNA methylation - demethylation of genes which regulate flowering.
The signal is remembered by cold treated cells, but resets every generation (meiosis).
Why is vernalization important for crops?
Delays flowering allowing crops to be harvested.
Crops such as spring and winter wheat.
What is the difference between short day plants (SDP) and long day plants (LDP)?
Short day plants flower when the day length is LESS than the critical value.
Long day plants flower when the day length is MORE than the critical value.
Where is daylength sensed and what is the signal?
Sensed in the leaves, then signal is transmitted to the SAM.
The signal is florigen
How are phytochromes involved in photoperiodical flowering?
- PhyB: represses flowering (LFR)
- PhyA: stimulates flowering (HIR)
- Cry: stimulates flowering
What is florigen?
Protein (FT) induced in the leaves, moves through the phloem to the SAM.
HD3A = equivalent in rice (LDP)
