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Question
Explain the sexual reproduction process in plants with a diagram.
Solution
Sexual reproduction in plants:
- A flower is the functional unit of sexual reproduction in plants.
- The androecium and gynoecium are the male and female parts of the flower respectively.
- The female reproductive organ of a flower which gives rise to egg or female gamete is known as carpel. Ovary present at the base of the carpel contains ovules that undergo meiosis to form embryo sac.
- Stamen is the male reproductive part of a flower which gives rise to male gametes.
- In sexual reproduction of plants, pollination is a major step, which involves the transfer of pollen grains on the stigma of female flower.
- Stigma becomes sticky during pollination.
- The pollen grain germinates over the stigma and gives rise to the pollen tube.
- Pollen tube carries two male gametes which are released near egg cells present in the embryo sac.
- One male gamete fuses with a female gamete giving rise to zygote. The second male gamete fuses with two polar nuclei giving rise to endosperm. This is called as double fertilization.
- Zygote develops into embryo and endosperm serves as a nutritive tissue for the growing embryo.
- After fertilization, the ovule develops into seed and ovary into fruit. Seeds fall upon the ground and can develop into a new plant under favourable conditions.
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RELATED QUESTIONS
A student while observing an embryo of a pea seed in the laboratory listed various parts of the embryo as given below:
Testa, Tegmen, Radicle, Plumule, Micropyle, Cotyledon.
On examining the list the teacher remarked that only three parts are correct. Select three correct parts from the above list:
(a) Testa, Radicle, Cotyleddon
(b) Tegmen, Radicle, Micropyle
(c) Cotyledon, Plumule, Testa
(d) Radicle, Cotyledon, Plumule
"The chromosomal number of the sexually producing parents and their offspring is the same." Justify this statement.
The reproductive part of a plant is the ______.
Fill in the following blank with suitable word :
The ovary of a flower becomes ....... after fertilisation.
Explain the terms 'self pollination'
Explain the term 'fertilisation'.
What changes take place in the flower after fertilisation which lead to the formation of seeds and fruit?
(a) Draw a neat diagram of a flower showing its various parts. In this diagram mark stem, receptacle, sepals, petals, stamen and carpel.
(b) What name is given to (i) all the petals of a flower, and (ii) all the sepals of a flower?
(c) What are (i) stamen, and (ii) carpel, in a flower?
(d) What is the other name of carpel of a flower?
(e) What is the name of yellow powdery substance present in the anther of a flower?
Which of the following is the correct sequence of events of sexual reproduction in a flower?
(a) pollination, fertilisation, seed, embryo
(b) seed, embryo, fertilisation, pollination
(c) pollination, fertilisation, embryo, seed
(d) embryo, seed, pollination, fertilisation
Which among the following statements are true for unisexual flowers?
(i) They possess both stamen and pistil
(ii) They possess either stamen or pistil
(iii) They exhibit cross pollination
(iv) Unisexual flower possessing only stamens cannot produce fruits
(a) (i) and (iv)
(b) (ii), (iii) and (iv)
(c) (ii) and (iii)
(d) (i), (iii) and (iv)
Put a tick mark (✓) against the correct alternative in the following statement
Pollen is produced in the:
Fill in the blanks:
A carpel consists of ________ , ________ and ________.
Fill in the blank:
Seeds are formed from________.
Mention the function of Flower.
Draw a diagram of the longitudinal section of a flower exhibiting germination of pollen on stigma and label (i) ovary, (ii) male germ-cell, (iii) female germ-cell and (iv) ovule on it.
Distinguish between unisexual and bisexual flowers giving one example of each. Draw a diagram showing process of germination of pollen grains on stigma and label the following parts:
(a) Female germ cell
(b) Male germ cell
(c) Ovary
Answer the following question.
How does suitable pollination lead to fertilization?
What is meant by pollination?
Pollen grains are formed by _________ division in locules of anthers.
Find an odd one out.
What does germination mean?
Where does the endothecium layer of anther lobes is present?
Generally, in a pollen tube, which of the following moves to the tip of the tube?
What would be the number of chromosomes of the aleurone cells of a plant with 42 chromosomes in its roots tip cells?
Conidia are formed endogenously while zoospores are formed endogenously.
Length of pollen tube depends on the distance between ______
Complete the table
| Carly x | ______ | ______ |
| ______ | petal | attract insects |
| Androecium | ______ | Male reproductive part |
| ______ | ______ | Female reproductive part. |
Which among the following statements are true for sexual reproduction in flowering plants?
- It requires two types of gametes
- Fertilisation is a compulsory event
- It always results in formation of zygote
- Offspring formed are clones
What is the structural unit of sexual reproduction in plant?
Name the reproductive parts of an angiosperm. Where are these parts located? Explain the structure of its male reproductive part.
In flowering plants, the pollen grains are transferred to stigma by pollination but the female germ cells are present in the ovary.
Explain with the help of a labelled diagram (only concerned parts), how the male germ cell reaches the ovary.
The pollen tube usually enters the embryo sac ______.
Given below is a diagram of a germinating seed. Label the parts that:
- gives rise to future shoot.
- gives rise to future root system.
- stores food.
State the post-fertilisation changes that lead to fruit formation in plants.
- Assertion: Primary endosperm nucleus is diploid.
- Reason: It is the product of double fertilisation.
