What is so interesting about
seeds?
Bill Finch-Savage
President: 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
Seeds are morphologically diverse
Crop Seeds
Wild seeds are even more diverse
Crop Seeds
Wild Seeds
Largest: Coco-de-mer palm (Lodoicea maldivica)
Smallest: epiphytic orchids
18 Kg --------------- 0.8 μg
> 9 orders of magnitude
For experiments we use:
Arabidopsis thaliana
Brassica oleracea (cabbage family)
Seed behaviour is complex:
Their potential for
germination continually
changes as a function of
temperature and
moisture
They sense the
environment and
respond to control
germination
Seeds are an
environmental
sensor
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Environmental
sensor
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Soil:
Nitrate
Environmental
sensor
Seed depth:
Alternating temp
Oxygen
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Soil:
Nitrate
Environmental
sensor
Seed depth:
Alternating temp
Oxygen
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Soil:
Nitrate
Environmental
sensor
Disturbance:
light
Seed depth:
Alternating temp
Oxygen
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Soil:
Nitrate
Environmental
sensor
Plant competition:
Wavelength
Nitrate
Alternating temp
Disturbance:
light
Seed depth:
Alternating temp
Oxygen
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Soil:
Nitrate
Environmental
sensor
Plant competition:
Wavelength
Nitrate
Alternating temp
Disturbance:
light
Sufficient water:
Water potential
Seed depth:
Alternating temp
Oxygen
Season:
Mean temp
Alternating temp
Wavelength
Nitrate
Oxygen
Soil:
Nitrate
Environmental
sensor
Plant competition:
Wavelength
Nitrate
Alternating temp
Disturbance:
light
Sufficient water:
Water potential
Schematic for molecular regulation of seed dormancy and germination
Environment
Hormone
synthesis
Hormone signalling
Response
Sensitivity changes
Levels
change
DOG1
ABA
MFT
GA
SPT
PIL5
Perception
GA regulated transcription
DELLAs
ABI4
PP2c [ABI1,ABi2 etc.]
SnrK2
ABI5
PYR/PYL/RCAR
ABi3
GID1a,b,c
GA regulated transcription
DELLAs
Integration
ABA induced
transcription
Spatial signal (e.g. Light)
GID1a,b,c
DOG1
CYP707A2
GA3ox1
PYR/PYL/RCAR
ABA induced
transcription
ABi3
GA
SPT
PIL5
NCED6
GA2ox2
ABI5
Induction
CYP707A2
GA3ox1
ABA
MFT
Seed sensitivity to spatial signals
Dormancy
Relief
NCED6
GA2ox2
Temporal response
Ambient
Environment
Dormancy
induction
ABI4
SnrK2
Relief
PP2c [ABI1,ABi2 etc.]
Germination