Flowering Flashcards
Transition at the shoot apex from a juvenile to
adult phase is controlled by a genetically
controlled
“developmental program”
•Transition is induced by certain environmental cues what are they?
temperature and photoperiod
define Photoperiod
numbers of hours of light during a 24 h D-N cycle that plant receives
____ (photoperiod) —-> _______ (messengers)—-> _______ (flowering)
signal, transduction, and response
who discovered photoperiod
- Garner & Allard (USDA scientists)
when was photoperiod discovered
1920s
what crop was photoperiod discovered with
tobacco
the photoperiodic behavior of flowering depends actually upon the length of the _____ period
dark
By this concept, a short-day plant should actually be considered as
long night plant
The relative length of light vs dark period is not the determining factor in photoperiodism but the actual uninterrupted length of the _____ period is critical
dark
short day plants:
initiate flowers when the light period
is shorter than critical day-length
long day plants:
initiate flowers when the light period is longer
than critical day-length
Day neutral:
Plants initiate flowers at any day-length
what onion is not well suited for Minnesota due to bulbing response to photoperiod
Bermuda photoperiod= ~12 hrs
what onion is better suited for Minnesota
Sweet Spanish photoperiod is more than 15 hrs
what are reasons photoperiod is important in nature
Over-wintering plants stop growing, set buds and become dormant in the fall (to develop cold hardiness), and Plants within a population flower uniformly for pollination
define “Latitudinal Ecotypes
Populations of plants within a
species are able to (genetically)
adapt to latitude
‘critical’ day length is longer for plants collected at more _______ latitudes
Northerly
Non-obligate short-day plant
Plants initiate flowers under any day-length, but will produce more flowers or flower more quickly under short days
