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SEED DORMANCY
 
 

 


Caused By
Type Dormancy
How Overcome?

1) Dry Seeds:
    dehydration of seed
quiescence
sow in moist environment 
2) Seed Coat Dormancy or
    Hardseededness:
    hard seed coat impermeable
    to water and gases
quiescence
scarification - physical or chemical abrasion of seed coat.
3) Embryo Rest:
    low growth promoters and/or
    high growth inhibitors
    in embryo
 rest 
(physiological dormancy)
stratification - cold (35-40 oF), moist storage or 4-12 weeks. 
4) Double Dormancy:
    hard seed coat plus embryo 
    rest
both quiescence
and rest
scarification then stratification
5) Chemical Inhibitors:
    inhibitors in pericarp (fruit
    wall) or testa (seed coat)
correlated
inhibition
I) if fleshy, remove fleshy pericarp
   (fruit wall) or testa (seed coat). 
2) if pericarp or testa is dry, leach
    in running water. 
6) Immature Embryo:
    underdeveloped or
    rudimentary embryo 
developmental dormancy
1) after ripening - store for 4-6
    weeks under ambient conditions 
2) warm stratification - warm moist 
    storage. 
3) embryo culture - excise embryo 
    and put in tissue culture
7) Light Requirement
    phytochrome in Pr form
secondary
dormancy
I) expose to any white light 
2) expose to red light 
3) sow shallow or on surface