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प्रश्न
Explain sexual reproduction in plants.
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उत्तर
- In sexually reproducing plants, flowers function as the reproductive organs.
- In flowers, the male organ is the stamen and the female organ is the carpel.
- Flowers which have both the male and female organs, i.e. stamens and carpels, are called bisexual flowers, whereas flowers which have either male or female organs are called unisexual.
- Male gametes, called pollen grains, are produced by stamens, and carpels produce female gametes, called ovules or egg cells, inside ovaries.
- Fertilization takes place in the ovule where the egg cell and pollen grain fuse.
- This fertilized egg cell later develops into an embryo and the entire ovule gets converted into a seed.
- Under favourable conditions, the seed germinates to give rise to a new plant.
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संबंधित प्रश्न
A student was asked to observe and identify the various parts of an embryo of a red kidney bean seed. He identified the parts and listed them as under:
I. Tegmen
II. Testa
III. Cotyledon
IV. Radicle
V. Plumule
The correctly identified parts among these are
(A) I, II and III
(B) II, III and IV
(C) III, IV and V
(D) I, III, IV and V
In the following diagram showing the structure of embryo of a dicot seed, what are the parts marked I, II and III sequentially?
(i) Name the part marked 'A' in the diagram.
(ii) How dose 'A' reachese part 'B'?
(iii) State the importance of the part 'C'.
(iv) What happens to the part marked 'D' after fertilisation is over?
"The chromosomal number of the sexually producing parents and their offspring is the same." Justify this statement.
Draw a neat sketch of the carpel of a flower. Mark in it stigma, style and ovary.
Explain the terms 'self pollination'
In tobacco plant, the male gametes have 24 chromosomes.
What is the number of chromosomes in the zygote?
Draw a neat diagram of a flower showing its various parts. In this diagram mark stem, receptacle, sepals, petals, stamen and carpel.
One of the following occurs in the reproductive system of flowering plants as well as that of humans. This is :
(a) vas deferens
(b) anther
(c) ovary
(d) style
In the figure given alongside, the parts marked A, B and C are sequentially:
The correct sequence of reproductive stages occurring in flowering plants is ______.
In what ways is fertilisation in a plant different from fertilisation in a human?
Fill in the blank:
Seeds are formed from________.
State whether the following statement is true (T) or false (F):
Flowers which possess stamens and carpel are called unisexual.
Find the odd-one out, giving reason:
Anther, pollen grain, ovule male gamete
Mention the function of Anther.
What are the male and female gametes in a flowering plant?
(a) Identify A, B and C in the given diagram and write their functions.
(b) Mention the role of gamete and zygote in sexually reproducing organisms.
“Cell division is a type of reproduction in unicellular organism.” Justify.
Prepare a slogan for campaign against female foeticide.
What is meant by pollination?
Find the odd one out:
Accessory whorls : Calyx and corolla : : essential whorls : ______________
Define.
Inflorescence
Give scientific reason.
Fertilization in plants is called double fertilization.
Observe the figure below. Write functions of the labelled parts.
Generally, in a pollen tube, which of the following moves to the tip of the tube?
Gloriosa superba exhibits ______.
What would be the number of chromosomes in the cells of the aleurone layer in a plant species with 8 chromosomes in its synergids?
In human beings, fertilization occurs in the ______
Which out of the following processes does not lead to the formation of clones.
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
State the number of sets of chromosomes present in a zygote.
Double fertilization is exhibited by ______
Triple fusion involves ______.
The pollen tube usually enters the embryo sac ______.
In male reproductive whorl of a flower the archesporial cells are formed by ______.
