"Absorption" PPT

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"Absorption" PPT

Part One: Situation Import

In 2011, northern my country suffered a severe drought that had not happened in a century. The drought led to a reduction in grain production. Why did the severe drought seriously affect crop yields?

learning target

1. Experimental observations show that green plants need water to live.

2. Identify the structural basis for green plants to absorb water - root hairs.

3. Understand and be able to explain the principles of water absorption and water loss in plant cells and root hairs.

Absorption PPT, Part 2: Exploration Topic 1

The water required for plant life is mainly absorbed by the roots from the soil.

1. The phenomenon of water absorption and water loss in cells

Life tips: Soak wilted cucumbers in water, and the cucumbers will gradually become firm; pour a small amount of soy sauce into a plate with cucumber strips, and more and more soup will appear on the plate, and the cucumber strips will gradually become firmer. Soft shrinkage. It shows that the pulp cells of cucumber can absorb water and lose water.

2. Water absorption and water loss conditions of cells

3. Life examples of cells absorbing and losing water

Focusing on the topic of "under what circumstances do plant cells absorb or lose water?", groups were divided into groups to conduct exploratory experiments.

Absorption PPT, Part 3: Exploration Topic 2

Observe root hairs

1. The structure of the root tip

2. The principle of water absorption by root hairs

(1) Conditions for root hairs to absorb water:

The concentration of root hair cell fluid > the concentration of soil solution

(2) The structure of root hairs is suitable for absorbing water

Characteristics: Thin cell wall, less cytoplasm, and large vacuoles.

Absorption PPT, Part 4: Collaborative Discussion

1. Which part of the root tip is the main water-absorbing area of ​​the root?

Mature area

2. How does the contact area between roots and soil expand?

A large number of root hairs can greatly increase the surface area for roots to absorb water and improve the efficiency of root water absorption, that is, increasing the amount of water absorbed by the roots per unit time.

Analytical thinking

1. In the process of plant cultivation, why does excessive fertilization at one time cause "seedling burning"?

When the concentration of the soil solution is greater than the concentration of the root hair cell fluid, the root hair cells not only cannot absorb water from the soil, but will cause the water in the cell fluid to seep into the soil, causing the plant to lose water, which is the phenomenon of "seedling burning".

2. Why do we need to bring a lot of soil to the roots when transplanting plants?

When transplanting plants, covering the roots with soil can well protect the young roots and root hairs. After transplanting, the plants can absorb moisture from the soil in a short time, which is beneficial to the survival of the transplanted plants.

Absorption effect PPT, part 5: training to meet standards

1. When pickling radish with salt, what happens to the radish? ( )

A. The cells absorb water and the radish stiffens B. Cells absorb water and radish shrinks

C. The cells lose water and the radish becomes stiff D. Cells lose water and radish shrinks

2. The structural characteristics of root hair cells are ( )

A. Thick cell walls, little cytoplasm, and large vacuoles

B． Thin cell wall, less cytoplasm, and large vacuoles

C. The cell wall is thick, the cytoplasm is abundant, and the vacuoles are small

D. The cell wall is thin, the cytoplasm is abundant, and the vacuoles are small

3. The reason why root hair cells can absorb water is ( )

A. The number of root hair cells is large and the absorption area is large

B． Root hair cells are in contact with soil solution

C. The vacuoles are large and the concentration of the cell solution is greater than that of the soil solution.

D. The vacuoles are small and the concentration of the cell solution is less than that of the soil solution.

4. The reason why the plants will wilt if too much fertilizer is applied at one time is ( )

A. The concentration of root hair cell fluid decreases B. Increased concentration of root hair cell fluid

C. The soil solution concentration is too high D. Soil solution concentration is too low

Keywords: Beijing Normal University edition seventh grade biology PPT courseware free download, absorption effect PPT download, .PPT format;

For more information about the "Lifestyle Absorption Effect of Green Flowering Plants" PPT courseware, please click the "Lifestyle Absorption Effect of Green Flowering Plants ppt" tab.

"Absorption" PPT courseware:

"Absorption Effect" PPT Courseware Part One: Situation Introduction Farmer's proverb says: Whether you harvest or not depends on water, and whether you harvest more or less depends on fertilizer. Can you understand the important role of fertilizers in agricultural production from the proverbs? Learning objectives 1. Describe the life of green plants through observation experiments..

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Update Time: 2024-11-21

This template belongs to biology courseware Beijing Normal University Edition Seventh Grade Biology Volume 1 industry PPT template

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