"Seeds germinate and form seedlings" PPT download

"Seeds germinate and form seedlings" PPT download

Part One: Situation Import

Information: Many crops are sown in spring. Before sowing, it is often necessary to pour some water on the ground to make the soil moist. If there has just been a light rain, you can sow without watering. However, if it is too wet, the seeds will easily become moldy. . Before sowing, the soil is often loosened to allow sufficient air in the soil.

What conditions are needed for seeds to germinate?

learning target

1. Explore the nutritional content of seeds.

2. Through group cooperative exploration, clarify the environmental conditions and own conditions for seed germination.

3. Use controlled experimental methods to design and complete research on "environmental conditions for seed germination" and learn to control experimental conditions.

Seeds germinate and form seedlings PPT, part 2 content: course exploration

Explore theme one

Explore the nutritional content of seeds

1. Exploration process

(1) Ask the question: What nutrients do seeds contain?

(2) Make assumptions: Seeds contain organic and inorganic substances

(3) Design and implement experimental plans

(4) Record experimental phenomena, analyze and draw conclusions

Experiments have shown that any plant seeds contain inorganic matter (moisture, inorganic salts) and organic matter (starch, protein, fat), and more organic matter than inorganic matter.

discuss:

1. When baking dry seeds in a test tube, why should the mouth of the test tube be slightly tilted downward?

Tip: Prevent water vapor from condensing and refluxing to burst the test tube.

2. How to determine whether seeds contain inorganic or organic matter?

Tip: Organic matter can burn, but inorganic matter cannot.

3. Which ingredient in flour turns blue when exposed to iodine?

Hint: starch.

4. What is the main component of the flexible substance in the dough?

Tip: Protein.

5. Why do you put wheat seeds on the fire to roast for a while?

Tip: Remove moisture

2. Internal conditions for seed germination

(1) Sufficient nutrients for embryo development

(2) A mature and complete embryo

(3) Viable and not in dormant period

3. Determine the germination rate of seeds

Before planting crops, it is necessary to select seeds and measure the germination rate of the seeds.

Explore theme two

external conditions for seed germination

Guess: What’s the reason these seeds didn’t germinate?

(There is a problem with the seeds themselves, or there is a problem with the environment in which the seeds exist)

hint:

1. The question we explore is what suitable environmental conditions are needed for seed germination.

2. Make assumptions about the problem based on your personal experience and inspiration from crop sowing.

3. There may be a variety of environmental factors that affect the germination of seeds. A single-factor experimental method should be adopted and a controlled experiment should be set up.

Discuss:

The issue will become clearer with each passing day

1. Is there a control group in this experiment? If so, which group is it? Why?

Tip: Yes; Group 3; Group 3 can germinate.

2. How many groups of controls were set up in the experiment? Which groups were they?

Tip: Three groups of comparisons. 1 and 3; 2 and 3; 4 and 3.

3. What conclusions can you draw from the analysis?

Tip: Appropriate amount of water, suitable temperature, and sufficient air are necessary for seed germination.

4. What impact will it have on the experimental results if only one seed is placed in the experimental device?

Tip: There is a lot of chance and the experimental error is big.

in conclusion:

When seeds germinate, they require an appropriate amount of water, a suitable temperature and sufficient air. Without any of these external conditions, seeds cannot germinate.

Seeds germinate and form seedlings PPT, the third part: training to meet standards

1. Which of the following is not a necessary condition for seed germination ( )

A. Sufficient sunlight B. Sufficient air

C. Suitable temperature D. Suitable amount of moisture

2. Under the following conditions, seeds can germinate normally ( )

A. Fertile, water-filled, warm soil

B. Cold, loose, well-watered soil

C. Warm, moist, soft soil

D. Warm, dry, soft soil

3. Can seedlings grow if rice and watercress are sown into the soil? Can fried seeds germinate if placed under suitable external conditions? Why?

cannot. Rice and watercress are incomplete embryos; the embryos of fried seeds are dead.

4. When Xiao Hong and Xiao Ming were exploring the external conditions for seed germination, they put 6 corn seeds with germination ability into two beakers A and B respectively as shown below. Place beaker A in a ventilated place at 25°C and beaker B in the refrigerator. Try to analyze the germination of seeds in two beakers.

Keywords: Beijing Normal University version of seventh-grade biology PPT courseware for free download, seed germination and formation of seedlings PPT download, .PPT format;

For more information about the PPT courseware "The Life History of Green Flowering Plants, Seeds Germinate and Form Seedlings", please click on the "The Life History of Green Flowering Plants, Seeds Germinate and Form Seedlings" ppt tag.

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