Dormancy

1
Dormancy
the temporary failure of a viable seed to
germinate after a specified length of time in a
particular set of environmental conditions that
later evoke germination when the restrictive
state has been terminated by either natural or
artificial means GM Simpson, 1990, Seed
Dormancy in Grasses
2
Steps in the Development of Dormancy in Seeds

• Loss of water (desiccation)
• Differentiation of the seed coat
• Cessation of gene transcription and protein
  synthesis
• Reduction of respiration and other activites of
  intermediary metabolism

3
Stages of Embryo Development
Phaseolus
4
Degradation of Protein Storage Bodies Following
Imbibition
4 hours after imbibition
5
RNA Expression During Embryogenesis
6
Cross Section of Maize Kernel
endosperm
embryo
7
Dark Grown abi3 Begins to Germinate
8
Germination Declines as Dormancy Progesses
aba germination
aba ABA
wild type germination
wild type ABA
9
Germination is Reduced by ABA
10
Maize viviparous
Mutation also affects anthocyanin production
11
lec1 Cotyledon Vasculature
12
leafy cotyledon-1
13
lec1Lacks Protein Storage Bodies
Wild type
lec1
14
Transport of Proteins to the Protein Storage
Bodies
15
Pathway of LEC1, FUS3, and ABI3 Function in
Embryo Development