4. Parts of a Seed
Seed coat
Endosperm – food store
Embryo – the baby plant
5. Seed coat
Protects the seed
Consists of 2 layers
1. Tegmen (inner; colorless)
2. Testa (outer; colored)
A scar called hilum can be
seen. It’s the mark left by
the funiculus that attaches
the ovule to the ovary
7. Embryo
The miniature (baby)
plant
Dominant (not active)
until some requirements
(ex. Water, sunlight) are
met
Has two basic parts:
hypocotyl and epicotyl
8. Embryo
Epicotyl – will become
shoot (leaves and stems)
via plumule; grows above
plant axis
Hypocotyl – connection
between cotyledon (seed
leaf) and radicle (baby
root); grows below plant
axis
9. Seed Germination
The process in which the
embryonic plant contained
within the seed grows.
The first to emerge is the
hypocotyl, then the
epicotyl.
A young plant called
seedling is now seen.
10. Factors Affecting Seed Germination
Water - causes seeds to swell and break open; when
H2O enters, it activates enzyme and the food is
broken down to useful chemicals for the new plant
Oxygen – for cellular metabolism; when the seed
breaks open, gas exchange can occur
Temperature – each plant species has a temperature
range within which the seeds will germinate
11. Seed Germination
As the seedling emerges from the seed coat
sending out roots and leaves, the stored
food is exhausted (used up).
The leaves by this time provides its own food
by photosynthesis.
12. Seed Germination
When these factors (water, oxygen,
temperature) are met, the seed could
germinate into a new plant.
