"Sowing and Germination" PPT courseware

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"Sowing and Germination" PPT courseware

What conditions are needed for seeds to germinate?

Explore

When exploring what conditions are required for seed germination, we need to list all the factors that may affect seed germination, such as seed shape, size, fullness, temperature, moisture, air, etc. These factors that affect seed germination are also called variables.

There are many variables that influence seed germination, but not all of them are equally important. For example, variables related to the seeds themselves (the shape, size, fullness of the seeds, etc.) are secondary variables. A certain method needs to be used to keep these secondary variables constant during the experiment.

So what are the secondary variables? Is there any way to keep them constant during the experiment? What are the main variables? (moisture, air, temperature)

2. The conditions for seed germination

Whether the seeds are in the dormant period, whether the seeds are alive,

Whether the structure of the seed is damaged by external adverse factors

Because the germination of seeds is also limited by its own conditions, which cannot be directly observed, it has a very important impact on the sowing of crops.

Within the same group, what are the differences in variables between seeds A and B, seeds B and C, and seeds A and C?

What are the differences between A seeds and B seeds between different groups? What about between B seeds and C seeds?

Is it possible to compare the germination of seeds B in group A and seeds A in group B?

The first three groups of pea seeds were the results after being placed at different ambient temperatures for 5 days. Observe which seeds sprout.

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?

This is related to the life cycle of crops and flowers, which require different external conditions in different seasons.

For example: external conditions such as sunlight and temperature.

Seeds will germinate if they meet the conditions for germination.

So, how do seeds germinate?

germination of seeds

Under suitable conditions, the germ, hypocotyl and radicle cells in the embryo begin to divide and grow. First, the radicle develops into a root. At the same time, the embryo gradually grows into a stem and leaves. In this way, a new plant that can live independently is born.

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 in pea seeds and the endosperm in wheat seeds provide nutrients needed for seed germination during seed germination.

Scientific inquiry:

Optimum temperature and moisture content for rice seed germination

Ask questions - establish hypotheses - design experiments - analyze experimental data - communicate and evaluate

1. Ask questions:

(1) If there is a new variety of rice, how should the optimal conditions for seedling cultivation be determined to obtain a higher germination rate?

(2) Seed germination requires air, water and a certain temperature. Assuming that air can meet the needs of seed germination under ventilated conditions, how to control the temperature and moisture content to find the most suitable temperature for seed germination and the moisture content of seeds?

(3) Ask the question: What is the optimal temperature for rice seed germination? What is the optimal moisture content?

2. Establish hypotheses:

(1) First check the information and investigate the optimal temperature and moisture content for germination of other rice seeds. Determine the ____________ and ____________ of the experiment.

(2) Set up several experimental points for experiments between the highest temperature and the lowest temperature, the lowest moisture content and the highest moisture content.

(3) Establish a hypothesis. Your hypothesis is __________.

3. Experimental design

(1) Variables involved in this experiment

Main variables: ______, ______, ______.

In order to explore the relationship with temperature in this experiment, the ______ conditions must be controlled to be the same. In order to explore the relationship with moisture content, the air and temperature conditions must be controlled to be the same.

Secondary variables include: ____________________, etc. These secondary variables should be controlled to be the same in this experiment.

(2) Determine the experimental plan: It should include experimental equipment and materials; experimental steps and procedures; experimental data recording forms.

Consolidation exercises

1. Which of the following soils is most conducive to seed germination?

A Warm, moist and loose soil B Warm, moist and firm soil

C. High temperature, moist and loose soil. D. Cold, moist and loose soil.

2. People often say that “the plan for a year lies in spring.” Spring is the sowing season for most crops. Which of the following reasons is incorrect:

A There is a lot of rain in spring B The temperature is suitable in spring

C The air is fresh in spring D Most seeds have just passed the dormant period

3. When seeds germinate

A The embryo develops into the stem first. B The embryo develops into the leaf first.

C The radicle develops into a root first D The endosperm shrinks first

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"Sowing and Germination" PPT courseware 2:

"Sowing and Germination" PPT courseware 2 1. The life of impatiens Impatiens cultivation method 1. Block the bottom hole of the flower pot with stones; 2. Fill in soft and fertile soil; 3. Prepare the soil; 4. Spread the seeds Seeds; 5. Cover with soil and pour appropriate amount of water; 6. Place the flower pot in a sunny place..

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Update Time: 2024-11-19

This template belongs to science courseware E-education edition third grade science volume 2 industry PPT template

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