Sunday , July 12 2020
NCERT 7th Class (CBSE) Science: Reproduction in Plants

NCERT 7th Class (CBSE) Science: Reproduction in Plants

Question: What is pollination? How does it lead to fertilization? Explain with the help pf a diagram.

Answer: The transfer of pollen grains from the anther to the stigma of a flower is called pollination. Pollination is of two type – Self Pollination and Cross Pollination. After pollination a thin tube called the pollen tube grows down from the pollen grain through the pistil. The pollen tube carries the male cell. It grows until it reaches the ovule and enters it. the male cell moves into the ovule and fuses with the egg to form the zygote which further develops into embryo.

Pollination

Question: How is sexual reproduction different from asexual reproduction?

Answer: Difference is as follows:

Sexual Reproduction
Asexual Reproduction
1. In sexual reproduction two parents one male and one female are required.
1. In asexual reproduction, only one parent plant is required.
2. The offspring have a mix of inherited genes.
2. The offspring is genetically identical to the parent.
3. In plants sexual reproduction occurs by the formation of seeds.
3. In plants asexual reproduction occurs without seeds.
4. Special organs for reproduction are required.
4. Special organs for reproduction are not required.
5. For example – Mangoes, Coconut, Hibiscus etc.
5. For example – Potato, Jasmine, Rose, Yeast etc.

Question: Explain the difference between self – pollination and cross pollination.

Answer: Difference is as follows:

Self-Pollination
Cross- Pollination
1. Transfer of pollen from the stamen to the pistil of the same flower.
1. Transfer of pollen from the stamen of one flower to the pistil of another flower of the same plant or different plants of the same kind.
2. External medium is not required.
2. External medium is required.
3. It occurs only in bisexual flower.
3. It occurs in both unisexual and bisexual flowers.

Question: What is artificial propagation of plants? Name four methods of artificial propagation.

Answer: The process of growing new plants by artificial methods is known as artificial propagation. The four methods are :

1. Grafting: This method is commonly used in horticulture to develop new varieties of fruit plants.

2. Cutting: In this method a healthy young branch of a plants having leaf buds is cut off and planted in moist soil.

3. Layering: A young branch is bent towards the ground and covered with moist soil.

4. Tissue culture: In this method a piece of tissue is cut off from the growing tip of a plant. and grown in laboratory condition by providing it with suitable nutrients in test tubes. The palnt is provided with the most hygienic condition.

Check Also

7th Class CBSE Science NCERT Book

Motion and Time: 7th Class NCERT CBSE Science Ch 13

Motion and Time 7th Class NCERT CBSE Science Chapter 13 Question: Give the basic unit of speed. …

2 comments

  1. How is sexual reproduction different from asexual reproduction?

    • In sexual reproduction two parent is present one male and one female .The offspring are not exact copies of either parent.

      In asexual reproduction only one parent is present .The resulting offspring are exact copies of the parent.

Leave a Reply

Your email address will not be published. Required fields are marked *