Fruit Ripening, Abcission, Senescence, Dormancy, etc. Flashcards
Ecological Function of Fruit Ripening
seed dipersal - make the seed container attractive to animals that will spread the seeds
ripeing - must happen when the seeds are mature
ripening&seed maturity - the plant must control the process
Ripening characteristics
sweetness - conversion of starch to sugar
softening due to breakdown of cell walls
less tartness due to decrease in acidity
increase in flavor compounds
color change
changes in respiration due to (above)
Control Mechanism
ripening and seed maturity happening together
Hormone used for ripening
ethylene
How does ethylene control ripening
stimulates production of enzymes that
- convert starch to sugar
- break down cell walls
- break down acids
Rise in respiration and cellular activity is called
climacteric
*not all fruits are climacteric fruits
Once the climacteric is started by a rise in ethylene production, it promotes itself and becomes
autocatalytic
Fruit ripening is a terminal or what process?
end point process
other terminal processes
senescence
abscission
dormancy
Senescence definition
death, degradation, of a tissue of organ (with age)
example: flower petals
Senescence function
stimulated by ethylene
is the active developmental process, in which some of the cellular contents are actively relocated via phloem to other parts of the plant for re-use
Abscission definition
separation of a plant organ or tissue from the plant
Abscission may occur
after senescence
at ripeness
in response to an environmental trigger or environmental stress
The mechanism to sense change in photoperiod is due to what pigment
phytochrome
Abscission function
invloves ethylene as an initiator and promoter
an active developmental process in which the abscission layer cells develop in such a way which leads to separation
