seed and germination

1. 1
SEED
what is a
seed
Parts of a
seed and
its’
purpose
Germination
process and
types
Types of
seeds
LEARNING FOCUS

2. SEED
 It’s a reproductive structure which disperses, and can survive for some
time.
 When a seed is exposed to proper conditions, water and oxygen are
taken in through the seed coat. The embryo's cells start to enlarge.
Then the seed coat breaks open and a root or radicle emerges first,
followed by the shoot or plumule that contains the leaves and stem.
 The warmer the environment, the faster the germination.
 Cases when proper conditions are not present, the seeds take longer
time to germinate.
 The seed coat protects the embryo until such time. Factors affecting
germination depends on moisture content, richness of soil,
temperature, light, fungi, insects etc.

3. Parts of a seed
 A seed contains a miniature
plant, called an embryo,
that can develop into a fully
grown plant.
 The outer shell of a seed,
called a seed coat,
protects the embryo.
 Inside the seed, a
nutritious material the
cotyledons provides food
to the embryo.
 The embryo has a baby
shoot and baby root.
A typical seed includes three
basic parts:
(1) an embryo,
(2) stored food
(3) a seed coat.

4. Types of seeds
 Fruit seeds – Mango, Papaya, Banana, Strawberries .
 Vegetable seeds – Beans, Okra, Beets, Tomatoes, Pumpkin.
 Flower seeds – Rose, Lily, Jasmine, Daffodils.
 Hybrid – When 2 variety of seeds are crossed for a 3rd
product. (artificial)
 Edible seeds – Grains (cereals, millets and legumes) Chia,
Hemp, Pumpkin, Legumes, Flax, Sunflower, Pine nuts, Poppy.
 Baby seeds - the type of seed that has been treated so that,
once it germinates, the plant remains small. (soft, tender and
sweet)
 Creole seeds - corn, beans, squash, melon, watermelon,
zucchini, and cucumber. (natural cross pollination)

5. Germination process
seed
Radicle,
root
Shoot
and plant
https://www.youtube.com
/watch?v=heU7J2580ug

6. Epigeal Germination Hypogeal Germination
 Epigeal germination is
when the germination of
a plant takes place
above the ground.
E.g., onion, beans,
cotton, castor.
 The cotyledons are
brought on the surface of
the soil along with the
shoot.
 Botanical term
indicating that the
germination of a plant
takes place below the
ground.
E.g. Mango, rice,
groundnuts, Maize.
 Cotyledons remain
below the soil surface.
Types of germination

7.  The hypocotyl has a
curved terminal part to
protect the plumule as it
comes out of the soil.
 The plumule comes out of
the seed by the elongation
of the hypocotyl.
 The energy for the growth
comes from the
cotyledons.
 The epicotyl has a
curved terminal part to
protect the plumule from
friction in soil particles.
 The plumule comes out
of the seed by the
elongation of the
epicotyl.
 The energy primarily
comes from the
endosperm.
Epigeal Germination Hypogeal Germination

8. Reflection time
 What is a seed?
 Name any three types of seeds?
 What is the use of a seed coat?
 Does germination take place when the soil is dry?
Explain.
 Explain hypogeal germination with examples.