WATCH IT GROW!!!SEEDS AND GERMINATION

Mahomet-Seymour High School

Would you Believe…

A corn plant is bigger than a Redwood Tree?

Wheat can live longer than an Oak Tree?

You Better Believe It…

CORN Redwood Tree

Wheat Oak Tree

Objectives…

Define what a seed is and describe its function.

Discuss the parts of a seed and describe their functions.

Compare and contrast a monocotyledon and a dicotyledon.

Understand the general requirements of germination.

Discuss the steps in germination.

What is a seed?

Seeds can be thought of as devices that protect embryos until they encounter conditions that are suitable for growth as independent plants.

What are the parts of a seed? Seed Coat: the outer protective layer of a

seed. Protects the seed from damage. Aids in Dormancy

Cotyledon: part of the embryo of the seed. Generally becomes the first leaves of the

plants to emerge. Endosperm: tissue within the seed that act

as food for the undeveloped embryo. Embryo: contains all of the parts for the

plant to grow.

What are the parts of a seed? Radicle: the part of the embryo that emerges

to produce a temporary root system. Hypocotyl: the part of the embryo that breaks

through the soil and forms a small stem. Only present in dicotyledons.

Epicotyl: the part of the embryo that emerges from the soil to produce the first leaves.

Hilum: present on pod seeds, this is the attachment point of the seed to the pod.

What are the parts of a seed?

Seed Coat Cotyledon (x1) Endosperm Embryo Epicotyl Radicle

Seed Coat Cotyledon (x2) Endosperm Embryo Radicle Hypocotyl Epicotyl

Monocotyledon Dicotyledon

Monocotyledon Dicotyledon

4 General Requirements for Germination… Water: needed for imbibition.

Causes seed to swell and embryo to grow. Oxygen: need for gas exchange.

Available in soil pore Temperature: soil temperature needs to

be at an appropriate level for growth. Can vary between plants

Light or Darkness: important for seeds that germinate on top of the soil.

What is dormancy?

Dormancy: a period of non-growth. Seeds need to remain

dormant until the conditions for growing are right.

Recently some seeds were found viable after 10-15 thousand years.

Most seeds have a viable life of 3-15 years

What are the stages in germination?

Monocotyledon1.Seed swells (imbibition)2.Radicle grows downward3.Epicotyl grows upward4.New leaves form and photosynthesis occurs 5.A new root system develops

What are the stages in germination?

Dicotyledon1.Seed swells (imbibition)2.Radicle grows downward3.Hypocotyl forms an arch (neck) and breaks through the soil4.Epicotyl receives light and photosynthesis begins5.New leaves form and the cotyledons fall off