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What is so interesting about
seeds?
Bill Finch-SavagePresident: International Society for Seed Science (2011-2014)
WHY are seeds so important:
• Seeds are time capsules containing the full genetic information for the survival
of a species or establishment of crops
• Seeds can tolerate desiccation enabling long-term storage for genetic
conservation and the establishment of an agricultural seed industry worth >10
billion US$ per annum
WHY are seeds so important:
• Seeds are time capsules containing the full genetic information for the survival
of a species or establishment of crops
• Seeds can tolerate desiccation enabling long-term storage for genetic
conservation and the establishment of an agricultural seed industry worth >10
billion US$ per annum
• Seed of just three crops, rice, maize and wheat constitute 2/3 of the worlds food
WHY are seeds so important:
• Seeds are time capsules containing the full genetic information for the survival
of a species or establishment of crops
• Seeds can tolerate desiccation enabling long-term storage for genetic
conservation and the establishment of an agricultural seed industry worth >10
billion US$ per annum
• Seed of just three crops, rice, maize and wheat constitute 2/3 of the worlds food
• Seeds are both the start and end of the plant life cycle. They are the only mobile
phase and therefore determine when and where the plant exists
Crop Seeds
Seeds are morphologically diverse
Crop Seeds
Wild Seeds
Wild seeds are even more diverse
Smallest: epiphytic orchids
Largest: Coco-de-mer palm (Lodoicea maldivica)
18 Kg --------------- 0.8 μg
> 9 orders of magnitude
For experiments we use:
Arabidopsis thaliana Brassica oleracea (cabbage family)
They sense the environment and respond to control germination
Seed behaviour is complex:
Their potential for germination continually changes as a function of temperature and moisture
Seeds are an environmental
sensor
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Soil:Nitrate
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Seed depth: Alternating temp
Oxygen
Soil:Nitrate
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Seed depth: Alternating temp
Oxygen
Disturbance:light
Soil:Nitrate
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Seed depth: Alternating temp
Oxygen
Disturbance:light
Plant competition:Wavelength
NitrateAlternating temp
Soil:Nitrate
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Seed depth: Alternating temp
Oxygen
Disturbance:light
Plant competition:Wavelength
NitrateAlternating temp
Sufficient water:Water potential
Soil:Nitrate
Environmental sensor
Season:Mean temp
Alternating tempWavelength
Nitrate Oxygen
Seed depth: Alternating temp
Oxygen
Disturbance:light
Plant competition:Wavelength
NitrateAlternating temp
Sufficient water:Water potential
Soil:Nitrate
Dormancy
induction
Dormancy
Relief
Am
bie
nt
Environm
ent
CYP707A2
GA3ox1
NCED6
GA2ox2
GA GID1a,b,c
DELLAs
GA regulated transcriptionSPT
PIL5
ABA SnrK2 ABA induced
transcription
PP2c [ABI1,ABi2 etc.]
PYR/PYL/RCAR
ABI4
ABI5
ABi3
GA GID1a,b,c
DELLAs
GA regulated transcriptionSPT
PIL5
ABA SnrK2 ABA induced
transcription
PP2c [ABI1,ABi2 etc.]
PYR/PYL/RCAR
ABI4
ABI5
ABi3
NCED6
GA2ox2
CYP707A2
GA3ox1
Environment
Hormone
synthesis Hormone signalling
Sensitivity changesLevels
change
Response
Germination
DOG1
MFT
DOG1
MFT
Perception Integration
Se
ed
se
ns
itiv
ity t
o s
pa
tia
l s
ign
als
Sp
ati
al s
ign
al
(e.g
. L
igh
t)
Ind
uc
tio
nR
eli
ef
Te
mp
ora
l re
sp
on
se
Schematic for molecular regulation of seed dormancy and germination