WATCH IT GROW!!! SEEDS AND GERMINATION Mahomet-Seymour High School
Dec 22, 2015
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