"Plant Reproduction" Biological Reproduction and Development PPT Courseware 4

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"Plant Reproduction" Biological Reproduction and Development PPT Courseware 4

think about it

1. Why has life continued on the earth since it appeared until now?

The most basic link is: living things through reproduction and development.

2. What are the reproductive methods of organisms on earth? Can you recall what you learned?

learning target

1. Describe sexual reproduction in plants.

2. Through observation, thinking and discussion, be able to list common methods of asexual reproduction in plants.

3. Through exploration activities, try plant cuttings.

1. Flowering and pollination

When the stamens mature, the petals and calyx open to reveal the stamens and pistils, a process called flowering.

After the flower opens, the anthers of the stamens burst and the pollen is released and falls on the stigma of the pistil. This process is called pollination.

2. Pollen tubes and double fertilization

After pollination, the pollen is stimulated by the secretion of mucus from the stigma, and pollen tubes germinate. Pollen tubes grow along the style toward the ovary. There are sperm inside the pollen tube.

3. Formation of fruits and seeds

Double fertilization is a fertilization phenomenon unique to green flowering plants.

What is sexual reproduction?

After the combination of the reproductive cells of both sexes, a fertilized egg is formed, and the fertilized egg develops into a new individual.

What is asexual reproduction?

The process of developing directly from the mother into a new individual without the combination of reproductive cells of both sexes.

Applications of asexual reproduction

1. Cuttings: For roses, grapes and other plants, you can cut branch segments with buds and insert them into the soil (sand or water). Soon these branch segments will take root and sprout and grow into new plants.

How should cutting materials be processed to ensure survival?

(1) Does the number of nodes on the cuttings affect the survival of the cuttings?

(2) Does the thickness of the branches taken affect the survival of the cuttings?

(3) Can the same kind of branches survive when cut in different seasons?

(4) Do different soil qualities affect the survival of cuttings?

(5) How should we manage the cuttings after cutting so that the cuttings can survive?

2. Layering:

3. Grafting: For fruit trees such as oranges and picks, their branches or buds can be grafted onto another plant, so that the cambium layers of the two are close to each other. Soon they will grow into one and become a new plant.

Notes on grafting:

1. In order to ensure the survival of the scion, the cambium layer of the scion and the rootstock should be tightly combined.

2. When binding with plastic tape, pay attention to tightening it to prevent rapid evaporation of moisture at the joint or entry of external rainwater.

plant tissue culture

Plant cells are totipotent:

Each cell of a plant contains all the genetic information of the species and thus has the genetic ability to develop into a complete plant.

The meaning of sexual reproduction

1. It can produce fruits and seeds and has strong resistance to adverse environments, which helps plants adapt to diverse environments.

2. Produce fruits and seeds, expanding the distribution range of plants.

3. Offspring have the genes of both parents, which is conducive to the evolution of organisms.

The meaning of asexual reproduction

1. Reproduce offspring quickly and in large numbers,

2. The variation is small and the excellent traits of the parents can be maintained.

Thoughts and Discussions

1. When planting chrysanthemums and aloe vera, one plant often turns into a clump. Can you explain this phenomenon? Will you divide them into many trees?

This is because they have strong sprouting ability. They can be propagated by dividing them.

2. Plant asexual reproduction is widely used in agricultural production. Can you give some examples? Are these plants also capable of sexual reproduction?

For example, for white potatoes, seedlings are grown first, and then cuttings are taken. Garlic, taro, etc. can also be propagated using underground stems. Most plants that reproduce asexually have the ability to reproduce sexually.

Standard training

1. (2011•Jining Test) Which of the following are developed from the sweet and juicy peach flesh, watermelon seeds, and sunflower seeds ( )

A. Ovary, ovary wall, ovule

B． Ovary, ovule, ovary wall

C. Ovary wall, ovule, ovary

D. Ovule, ovary, ovary wall

2. (2010•Changchun High School Entrance Examination) Many organs of plants can reproduce offspring. Reproduction with the following organs belongs to sexual reproduction ( )

A. Ye B． Root c. Stem D. seed

3. (2011•Shiyan Test) There is a high-quality grape plant and I want to expand its planting. Which reproduction (reproduction) method is more suitable ( )

A. Cuttings B. Grafting C. Layering D. propagate by seeds

4. In agricultural production practice, a group of plants that generally use vegetative organs for reproduction are ( )

A. Sunflowers and watermelons b. sweet potatoes and potatoes

C. Peanuts and rice D. radish and cabbage

5. The 10,000-acre peach orchard in a certain county has beautiful scenery. However, with the growth and production in recent years, the yield has gradually decreased and the quality is poor. After investigation, it was decided to introduce new peach varieties. Your rationalization suggestion is ( )

A. Grafting using fruit branches

B． propagation from seeds

C. Using fruit branches for cuttings

D. Change all

Plants have various reproductive methods. What does this mean for plants?

Asexual reproduction: Such as potatoes and bamboo, which produce offspring individuals relatively quickly (sexual reproduction generally takes a longer time), which is conducive to the reproduction of a large number of individuals in a short period of time under suitable environmental conditions, and the traits of the offspring are relatively consistent.

Sexual reproduction: The seeds, fruits, etc. produced can often tolerate adverse environmental conditions and are easily spread to other places through various media, expanding the distribution range of plants. Sexual reproduction can make offspring have the genes of both parents, have a stronger ability to adapt to environmental changes, and is more evolutionary meaningful.

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For more information about the PPT courseware "Reproduction and Development of Organisms and Reproduction of Plants", please click the Reproduction and Development of Organisms ppt Reproduction of Plants ppt tag.

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Update Time: 2024-11-22

This template belongs to biology courseware People's Education Edition Biology for Grade 8, Volume 2 industry PPT template

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