1. What is a Seed?
We will learn more details later to answer this question.
For now:
Seed Coat: a surface tissue to keep seed dry inside
Storage Tissue: could be a separate tissue (endosperm = inside seed) or part of the embryo (often cotyledons)
Dormant Embryo: a small diploid plant with minimal metabolism (“suspended animation”)

2. Capsella Seed: Embryo Seed Coat Shoot Apex Endosperm
Cotyledons - dicot
Hypocotyl
Radicle
Root Apex
Micropyle

3. Seed Germination: Water Warm Temperature
Emergence of Radicle through Seed Coat
Seeds lacking dormancy need:
Water
Warm Temperature
So if you want to store seeds what are the conditions?
Dry Cold
Dormant seeds need more than moisture and warmth:
Dormancy is caused by:
Is overcome by:
Example:
nick digest
scrub fire
freeze-thaw cycles
Thick Seed Coat
Scarification
Kentucky Coffee Tree or
Thin Seed Coat
Light
Dark
Lettuce
Pea
Insufficient Development
Soil Fungus Association
Orchids
Inhibitor: Abscisic Acid
Stratification > Vernalization
Most CT feral plants
6 weeks at 4° C
20° C
Inhibitor: Phenolics
Leaching by Repeated Rain
Cacti

4. Barley Seed Germination
hydrolysis
starch
Fruit + Seed Coat
maltose
Endosperm
sugar
exocytosis
Aleurone Layer
cotyledon
monocot
-amylase
Storage Protein
translation
hydrolysis
shoot apex
RNA
Amino Acids
growth
Embryo
DNA
transcription GA
radicle apex
water
imbibition

5. Lettuce Seed Germination Embryo phytochrome hydrolysis starch
Seed Coat
shoot apex
sugar
cotyledons
-amylase
dicot
translation
RNA
growth
transcription
Embryo
DNA
radicle apex
phytochrome
photoreversibility
red and white light stimulate germination
660 nm
Pfr Pr
water
photoactivation
730 nm
imbibition
dark