1. THE CONTROL OF FLOWERING
PLANTS FLOWER AT DIFFERENT TIMES OF THE YEAR.
HOW DO PLANTS KEEP TRACK OF THE SEASONS?
WHICH ENVIRONMENTAL SIGNALS CONTROL FLOWERING?
HOW DO ENVIRONMENTAL SIGNALS BRING ABOUT THE TRANSITION TO FLOWERING?

2. FLOWERING IN ARABIDOPSIS
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3. VEGETATIVE VS. FLOWERING SHOOT APEX IN ARABIDOPSIS
VEGETATIVE APEX
FLOWERING APEX
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4. FLORAL EVOCATION
THE EVENTS OCCURRING IN THE SHOOT APEX THAT SPECIFICALLY COMMIT THE APICAL MERISTEM TO PRODUCE FLOWERS

5. FLORAL ORGANS ARE INITITATED IN SUCCESSIVE WHORLS
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6. MUTATIONS IN FLORAL ORGAN IDENTITY GENES
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7. THE ABC MODEL FOR FLORAL ORGAN IDENTITY
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10. QUADRUPLE MUTANT (ap1, ap2, ap3/pi, ag) RESULTS IN THE PRODUCTION OF LEAF-LIKE STRUCTURES IN PLACE OF FLORAL ORGANS
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11. THE SHOOT APEX AND PHASE CHANGES
THE SHOOT APICAL MERISTEM PASES THROUGH THREE DEVELOPMENTAL PHASES:
1. THE JUVENILE PHASE
2. THEADULT VEGETATIVE PHASE
3. THEADULT REPRODUCTIVE PHASE

12. JUVENILE AND ADULT FORMS OF ENGLISH IVY (Hedera helix)
(GIBBERELLIN CAUSES REVERSION OF ADULT FORM TO JUVENILE FORM IN ENGLISH IVY)
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15. FLORAL EVOCATION: COMPETENCE AND DETERMINATION
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17. PHOTOPERIODISM: MONITORING DAY LENGTH
PLANTS CAN USE CIRCADIAN RHYTHMS TO MEASURE DAYLENGTH

18. PLANTS CAN USE CIRCADIAN RHYTHMS TO MEASURE TIME
Entrained rhythm
Free running rhythm
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20. DAY LENGTH VARIES WITH LATTITUDE
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21. DAY LENGTH VARIES WITH THE MONTH OF THE YEAR AND THE LATTITUDE, EXCEPT AT THE EQUATOR
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Day length = night length all year at the equator

22. THE DISCOVERY OF PHOTOPERIODISM
GARNER AND ALLARD (1920s) AT USDA LAB AT BELTSVILLE, MD STUDIED FLOWERING IN MARYLAND MAMMOTH TOBACCO PLANT.
MARYLAND MAMMOTH WAS A SINGLE GENE MUTANT TOBACCO THAT DIDN’T FLOWER IN THE SPRING OR SUMMER, LIKE WILD TYPE.
IT ONLY FLOWERED WHEN BROUGHT INTO THE GREEN HOUSE IN THE WINTER.

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24. PLANTS CAN BE CLASSIFIED ACCORDING TO THEIR PHOTOPERIODIC RESPONSES
Short Day Plants (SDPs) flower when day length is shorter than a critical day length.
Long day plants (LDPs) flower when the day length is longer than a critical daylength.
Long-short-day plants (LSDPs) flower after a sequence of long days followed by short days.
Short-long-day plants (SLDPs) flower after a sequence of short days followed by long days.
Day-neutral plants (DNPs) are insensitive to daylength, Flowering is under internal developmental control.

25. THE SITE OF PERCEPTION OF THE PHOTOPERIODIC STIMULUS IS THE LEAF

26. EFFECT OF DAY LENGTH ON FLOWERING IN SDPs AND LDPs
Critical day langth
Critical day langth
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27. NIGHT BREAK EXPERIMENTS DEMONSTRATE ROLE OF NIGHT PERIOD IN SDPs
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28. NIGHT BREAK EXPERIMENTS ALSO DEMONSTRATE ROLE OF NIGHT PERIOD IN LDPs
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29. THE LENGTH OF THE DARK PERIOD REGULATES THE PHOTOPERIODIC RESPONSES IN BOTH SDPs AND LDPs
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30. NIGHT BREAKS GIVEN AT DIFFERENT TIMES DURING THE NIGHT PERIOD REVEAL CIRCADIAN RHYTHMICITY
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31. ACCORDING TO THE COINCIDENCE MODEL, THE EFFECT OF THE NIGHT BREAK DEPENDS ON THE RHYTHM OF LIGHT SENSITIVITY
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(SDP Soybean)

32. PHYTOCHROME IS THE PIGMENT INVOLVED IN MEASURING THE NIGHT LENGTH
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33. AS IN THE CASE OF SDPs, ACCORDING TO THE COINCIDENCE MODEL, THE EFFECT OF THE NIGHT BREAK DEPENDS ON THE RHYTHM OF LIGHT SENSITIVITY
LDP Arabidopsis
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34. VERNALIZATION: PROMOTING FLOWERING WITH COLD TREATMENT (40 DAYS AT 4C)
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Winter-annual Arabidopsis with vernalization
Winter-annual Arabidopsis without vernalization

35. VERNALIZATION: SITE OF PERCEPTION
THE SITE OF PERCEPTION OF
VERNALIZATION IS THE SHOOT TIP

36. DEVERNALIZATION
THE EFFECT OF COLD TEMPERATURE IN PROMOTING FLOWERING CAN BE REVERSED BY WARM TEMPERATURE (DEVERNALIZATION)

37. VERNALIZATION BLOCKS THE EXPRESSION OF THE GENE FLOWERING LOCUS C (FLC)
Winter annual without cold
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Winter annual without cold, but with FLC mutation
Winter annual after 40 cold days
FLC mRNA

38. GRAFTING STUDIES GRAFTING STUDIES HAVE DEMONSTRATED THE ROLE OF A
TRANSMISSIBLE STIMULUS PRODUCED BY
LEAVES WHEN PHOTOPERIODICALLY
INDUCED.

39. DEMONSTRATION OF LEAF-GENERATED FLORAL STIMULUS (FLORIGEN) IN THE SDP PERILLA
Induced graft donor leaf
Uninduced graft donor leaf
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40. SUCCESSFUL TRANSMISSION OF FLORAL STIMULUS BY INTERGENERIC GRAFTING
Scion: LDP Petunia hybrida, induced with long days.
Stock: Nonvernalized, cold-requiring LDP Hyascyamus niger (henbane)
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42. THE PHENOMENON OF INDIRECT INDUCTION
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43. MULTIPLE INDUCTION BY A SINGLE INDUCED LEAF
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