"The Life of a Plant" PPT

"The Life of a Plant" PPT

Part 1: Experiment:

1. Observe the soaked bean seeds:

(1) Observe the appearance of kidney bean seeds:

Can any student describe the shape of kidney bean seeds?

(2) Combined with the pictures in the book, understand the structure of kidney bean seeds

Structure of Phaseolus vulgaris seeds:

The seed coat is very tough and protects the internal structure of the seed.

There is a dark scar on the seed coat on the sunken side of the seed, which is the hilum, which is the trace of the seed being implanted in the pod. There is a small hole near the hilum, which is the seed hole.

When we pinch the seeds hard, water will flow out of the seed hole, indicating that the seed hole is the door for water to enter the seed.

Life of a plant PPT, part 2: 1. Structure of seeds

1. Structure of kidney bean seeds:

(1) Seed coat

germ

(2)Embryo hypocotyl

radicle

Cotyledons

The embryo is the new generation of larvae, and the new generation of plants develops from various parts of the embryo.

Cotyledons - provide nutrients

Germ - stem and leaves

radicle - root

Hypocotyl - the part that connects the stem to the root

2. Observe the swollen corn seeds

(1) Use a blade to cut the corn seed longitudinally in the center, and use a magnifying glass to observe the embryo of the corn seed based on the structural diagram in the book.

(2) What changes can be seen when iodine solution is dropped on the cross-section of corn seeds?

3. Comparison table of bean seeds and corn seeds

4. Classification of seeds

think?

1. Which part of the structure of beans and other legume seeds is the main part that people eat?

2. Which part of the structure of wheat seeds is flour mainly processed from?

3. Are the bean seeds a dicot or a monocot? Do they have endosperm?

Class exercises

1. The above pictures are schematic structural diagrams of corn seeds and kidney bean seeds respectively:

In the picture above, 1 is _____ (corn also includes ____); 2 is ____; 3 is ____; 4 is ____; 5 is ____; 6 is ____; 7 is ____.

2. Plant seeds are rich in nutrients. In seeds with endosperm, nutrients are mainly stored in the endosperm, while in seeds without endosperm, nutrients are mainly stored in -------------- ------( )

A． In the seed coat B. in cotyledons

C. In the germ D. in embryo

3. In plant seeds, the structure that can be called a new plant larvae is ( )

A. Endosperm B. Cotyledons C. Germ D. Embryo

4. When the wheat seed embryo grows into a seedling, the nutrients it needs come from

A. Endosperm B. Cotyledon C. Germ D. Soil ( )

Life of a plant PPT, part 3: 2. Conditions for seed germination

Adequate moisture, air and moderate temperature. These three conditions must be met at the same time, and one of them is indispensable.

discuss

Why do crops and flowers have to be sown in certain seasons and in moist and loose soil?

Because the germination of seeds requires suitable temperature and moisture.

Seeds will germinate if they meet the conditions for germination. So, how do seeds germinate?

think?

After the seedlings grow, the cotyledons in pea seeds and the endosperm in wheat seeds will shrink or even disappear. Do you know what role they play in seed germination?

The cotyledons and endosperm provide nutrients needed for seed germination during seed germination.

Life of a plant PPT, part 4: 3. Bud development

After the seed germinates, the radicle breaks through the seed coat and gradually forms a root. At this time, the embryo also gradually develops into stems and leaves. So how do the seedlings produced by germination of seeds grow into plants with lush branches and leaves? This has to do with bud development.

Buds are undeveloped stems, leaves or flowers. Under the conditions of suitable temperature, sufficient water and nutrients, the growth point cells at the top of the bud will continue to divide, and the bud axis will gradually elongate. The leaf primordia on the shoot axis will also develop into young leaves and gradually grow up.

The growth of terminal buds will grow the stem of the plant; the growth of lateral buds will form side branches on the plant body.

1. Structure of buds

The growth point is located at the top of the leaf bud, which causes the bud axis to continuously elongate.

Leaf primordium is located around the growth point - the young leaf.

Young leaves are located on the outside of the leaf primordium, --- leaves.

The bud axis is located at the central axis of the bud, the stem.

The bud primordia is located in the axils of young leaves, --- lateral buds.

2. According to the location of the buds

Terminal bud: The bud that grows at the top of the main stem or side branch is called terminal bud;

Lateral buds: buds that grow on the main stem or side branch nodes are called lateral buds.

Consolidate it

1. Seed germination is when the radicle develops into ____, the embryo develops into ____, and the nutrients stored in the cotyledons or endosperm are used for seed germination.

2. In a plant, the terminal buds tend to develop faster. When vegetable farmers plant many vegetables, they often remove the top buds in order to promote __________

3. In the structure of buds, cells will continue to divide, and the structure that makes the bud axis continue to elongate is ----- ( )

A． Shoot primordia B. Leaf primordium C. Young sprouts D. growing point

4. The structure of the bud that will develop into leaves is---- ( )

A． Shoot primordium B. Leaf primordium C. Young sprouts D. shoot axis

Life of a plant PPT, part 5: 4. Flower structure

Observe the structure of flowers

(1) The basic structure of a flower (taking peach blossom as an example)

1 flower stalk

Support flowers so they can spread out in space

2. Tori

Each part of the flower is attached to the receptacle

3. sepals

petal

Protect stamens and pistils before flowers open

4. Corolla: composed of petals

5. Stamens (multiple)

Anthers (containing pollen)

Filaments (supporting the anthers)

6. Pistil (one)

stigma

style

Ovary (contains ovules)

Life of a plant PPT, Part 6: 5. Plant growth period

Plants have a life cycle just like animals.

Plants and animals go through stages such as birth, growth and development, reproduction, and death throughout their lives.

What does this mean?

All living things have similar growth cycles. Life does not disappear with the death of an individual, but continues in this recurring cycle.

Keywords: Zhejiang Education Edition seventh grade science PPT courseware for the second volume free download, plant life PPT download, .PPT format;

For more information about the "Life of a Plant" PPT courseware, please click on the "Life of a Plant" ppt tag.

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