Plant Life Cycle
4.01 Explain the growth process of plants.
When a seed has sunlight,
air, water, and nutrients
it will begin to germinate,
or start to grow.
This young plant that
grows from a seed is
called a seedling.
Seeds
• Seeds are formed in the center part of
the flower or fruit.
• Seeds come in many shapes and sizes.
• Mature, fertilized ovules!
What is seed?
• A mature ovule containing an
embryo
• The sexual reproductive unit in a
plant
• Consists of 4 parts:
– Embryo
– Storage tissue
– Seed coat
– Seed leaf (Cotyledon)
Parts of a Seed
• Seed Coat
• Seed Leaf
• Stored Food
• Developing Plant
Embryo
• A complete
miniature plant in
resting stage
– Each has a root,
stem, or one or
two seed leaves
(called
cotyledons)
• Divided into 2
parts:
– Hypocotyl
• Forms lower stem
and roots
– Epicotyl
• Forms all plant
part above first
node
Stems-Internal
• Monocot : examples: corn, grasses
Monocot
Vs Dicot
• Dicot: example: trees
Storage Tissue
• Stored food to be used by plant in
first stages of growth
• Stored in endosperm in corn
• Stored in cotyledon in beans
The hard covering that
protects the seed
(endosperm & embryo) is
the ...
First to emerge through a
protective sheath….
Emerging shoot that
becomes the stem….
How Seeds Are Scattered
• Planting
• Animals
• Water
• Wind
http://www.pbs.org/wnet/nature/episodes/th
e-seedy-side-of-plants/video-shootingseeds-burrowing-seeds/4665/
About seeds
The fruit
breaks open.
The seeds fall.
The wind
blows the plant
and the seeds
fall out.
About seeds
dandelion
Some seeds
have
parachutes.
The wind
blows the
seeds away.
Some seeds
have wings.
They fly through
the air for a long
way.
About seeds
Animals help
disperse some
seeds.
How a Seed Grows into a New Plant
• The life of a plant begins as a seed.
• Once you plant and water a seed it begins to
germinate.
• The root pushes through the seed coat.
• The seedling grows out of the ground.
• The stem and its leaves point to the sunlight.
• The leaves make its own food.
• Flowers begin to bloom and make seeds.
• New seeds are formed and scattered.
What is this process called?
OTHERWISE KNOW AS
SEXUAL REPRODUCTION!
The life cycle of a plant
Roots
grow
from a
seed.
The life cycle of a plant
Roots
grow
from a
seed.
Leaves
start to
grow.
The life cycle of a plant
Roots
grow
from a
seed.
Leaves
start to
grow.
More
leaves
grow.
Flower
buds
appear.
The life cycle of a plant
Roots
grow
from a
seed.
Leave
s start
to
grow.
More
leaves
grow.
Flower
buds
appear.
The
flowers
open.
The life cycle of a plant
The petals die. The
flowers make a fruit
with seeds inside.
The life cycle of a plant
The petals die. The
flowers make a fruit
with seeds inside.
The fruit dries
and falls.
How deep???
•Depends on size of seeds
•Plant no more that 1 ½ times the
diameter of the seed.
Larger seeds are planted deeper
Smaller seeds are planted
shallow
• Water small seeds from the
bottom by soaking to prevent
burying them
Germination rate
•The % of seeds that sprout
Example 75 of 100 = 75%
•Are affected by temperature and
moisture
•Vary depending on type of plant and
quality (viability) of the seed
•Seed viability is the seed’s capability of
growing or developing.
Seedlings
•
The first sets of leaves are call
cotyledons
1. Monocots produce one seed leaf
2. Dicots produce two seed leaves
• True leaves are the second set of
leaves
• Transplant seedlings when the first
true leaves appear
•
Before planting in the outdoor
envionment, reduce humidity and water
and make the environment more like the
outside to “Harden off” plants.
Sexual propagation
Advantages
1. It is a fast way to get many plants
2. It is easy to do
3. It is economical
Disadvantages
1. Some plants, especially hydrids, do not
reproduce true to parents
2. Some plants are difficult to propagate from
seeds