Plant Life Cycle4.01 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– Developing plant

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

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…. Radicle

Emerging shoot that becomes the stem….

Seed Coat

Plumule

How Seeds Are Scattered

• Planting

• Animals

• Water

• Wind

About seeds

The wind blows the plant and the seeds fall out.

The fruit breaks open. The seeds fall.

About seeds

Some seeds have parachutes. The wind blows the seeds away.

Some seeds have wings. They fly through the air for a long way.

dandelion

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?

Life Cycle of a Plant

OTHERWISE KNOW AS SEXUAL REPRODUCTION!

The life cycle of a plantRoots grow from a seed.

The life cycle of a plantRoots grow from a seed.

Leaves start to grow.

The life cycle of a plantRoots grow from a seed.

Leaves start to grow.

More leaves grow. Flower buds appear.

The life cycle of a plantRoots grow from a seed.

Leaves start to grow.

More leaves grow. Flower buds appear.

The flowers open.

The life cycle of a plantThe petals die. The flowers make a fruit with seeds inside.

The life cycle of a plantThe petals die. The flowers make a fruit with seeds inside.

The fruit dries and falls.

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.

How deep???• Depends on size of seeds• Plant no more that 1 ½ times the diameter of the seed.

Larger seeds are planted deeperSmaller seeds are planted shallow

• Water small seeds from the bottom by soaking to prevent burying them

Seedlings• The first sets of leaves are call

cotyledons1. Monocots produce one seed leaf2. 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.

Advantages1. It is a fast way to get many plants2. It is easy to do3. It is economical

Disadvantages1. Some plants, especially hydrids, do not

reproduce true to parents2. Some plants are difficult to propagate from

seeds