"Why Flowers Bloom and Fall" PPT free download

Hunan Education Edition fourth grade science volume 2, why flowers bloom and fall PPT free download

Part 1 Chapters

review

What are the parts of the flower structure?

Sepals, petals, receptacle, stamens.

What aspects of a plant's life did we observe?

Germinate - grow - bloom - bear fruit

Why Flowers Bloom and Fall PPT Part 2 Chapter

Knowledge expansion (classification of flowers)

Like peach blossoms and cabbage flowers, those with all four parts including calyx, corolla, stamens and pistils are called "complete flowers".

Like pumpkin flowers and mulberry flowers, those that are missing one, two or three parts are called "incomplete flowers".

Why do flowers bloom and fall? PPT Part 3 Chapter

Classroom meets standards

1. My gains:

(1) The structure of a peach blossom includes: ( ), ( ), ( ) and ( ) four parts. A flower that has four parts like a peach blossom is called ( ); a flower that lacks one, two or three parts is called ( ).

(2) Common complete flowers include: ( ), ( ), ( ), etc. Common incomplete flowers include ( ), ( ), ( ), etc.

Why Flowers Bloom and Fall PPT Part 4 Chapter

Pollination of flowers:

Flowers develop from flower buds. Flower buds are formed from flower buds, and then the perianth unfolds to reveal the stamens and pistils. There are anthers on the top of the stamens. When the pollen in the anthers matures, it will be transferred to the top of the pistil through various media. This process is called pollination.

In layman's terms, pollination refers to the process of pollen falling from the anthers to the stigma of the pistil. There are two ways of pollination, one is self-pollination; the other is cross-pollination.

self-pollination

When pollen falls on the stigma of the same flower, it is called self-pollination. In nature, there are relatively few self-pollinating plants. Common plants in our lives such as wheat, rice, sorghum, soybeans, etc. are all self-pollinating plants.

cross-pollination

Pollen is transferred to the stigma of another flower by external force, which is called cross-pollination. Typical flowers include chrysanthemums and rye flowers.

Most plants are cross-pollinated, and pollen is spread mainly by wind and insects. Flowers that rely on wind pollination are called wind-pollinated flowers, such as corn, poplar, elm, rye flowers, etc. Flowers that rely on insects for pollination are called insect-pollinated flowers. Most of the brightly colored and fragrant flowers we usually see are insect-pollinated flowers, such as rapeseed flowers, chrysanthemums, etc.

Why Flowers Bloom and Fall PPT Part 5 Chapter

discuss

Not all pollen can land on the stigmas of the same flower, and not all stigmas can get pollen from the same plant. If the pistils are not fertilized by pollen during flowering, the plant will gain nothing from its efforts to bloom.

1. If the plant mother wants you to help her, what solutions do you think can be taken?

2. What do you think is the fastest way to achieve results?

Think about it: in life, we often find that the ears of corn have missing kernels; when eating melon seeds, the kernels are often hollow. What causes this? What is the solution?

Mainly caused by insufficient pollination.

The solution is: artificial assisted pollination

Why Flowers Bloom and Fall PPT Part 6 Chapter

practise

1. During the flowering season of fruit trees, if you encounter continuous rainy weather, the yield of fruit trees will often be reduced. What is the reason?

Answer: This is because the pollination of fruit trees is affected. For example, fruit trees that rely on insect pollination are restricted in their flight, resulting in insufficient pollination, resulting in reduced yields; fruit trees that rely on wind pollination also suffer from reduced yields due to rainy weather that prevents pollen from being spread by the wind.

2. Some flowers bloom but do not bear fruit. For example, most of the flowers of cucumbers, pumpkins, and loofahs will not bear fruit. Have a chance to observe and explain this phenomenon.

Answer: The flowers of these plants are either male or female. Male flowers will not bear fruit.

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"Why Flowers Bloom and Fall" PPT download:

Hunan Education Edition Fourth Grade Science Volume 2, Why Flowers Bloom and Fall PPT Download Part 1 Chapter Description: Little Knowledge The Origin of Flowers Flowers are transformed from leaves. From the appearance, the flower is a shortened branch. This abnormality Branches are suitable for reproduction. The various parts of the flower such as sepals,...

"Why Flowers Bloom and Fall" PPT courseware download:

Download the PPT courseware of Hunan Education Edition, fourth grade science volume "Why Flowers Bloom and Fall" PPT courseware download Activity 1: Observe which parts a flower is made up of and the number of each part. Activity 2: Draw a structural diagram of a flower. Please explain this The design concept of the work puts the name of each part...

"Why Flowers Bloom and Fall" PPT courseware:

Hunan Education Edition fourth-grade science textbook "Why Flowers Bloom and Fall" PPT courseware Warm Tips 1. Anatomy requirements: When dissecting, tear off each part in the order from outside to inside. Be careful during the dissection operation and do not damage the quilt. For the anatomy part, the torn parts must be divided into rows and classified...