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