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प्रश्न
Give scientific reason.
Fertilization in plants is called double fertilization.
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उत्तर
- The pollen grain germinates over the stigma and gives rise to pollen tube.
- The pollen tube bursts and releases two male gametes in the embryo sac.
- One male gamete fuses with the egg cell to form the zygote, whereas the second male gamete fuses with two polar nuclei in the embryo sac to form an endosperm.
- Since, in flowering plants, the process of fertilization occurs twice in the same embryo sac, by two male gametes, it is called as double fertilization.
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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
The reproductive part of a plant is the ______.
Fill in the following blank with suitable word :
The ovary of a flower becomes ....... after fertilisation.
Fill in the following blank with suitable word :
The female organ of reproduction in the flower is the...........
Draw a neat sketch of the carpel of a flower. Mark in it stigma, style and ovary.
Explain the term 'fertilisation'.
Name the part of a seed which grows into root.
What changes take place in the flower after fertilisation which lead to the formation of seeds and fruit?
In the figure given alongside, the parts marked A, B and C are sequentially :
(a) cotyledon, plumule and radicle
(b) plumule, radicle and cotyledon
(c) plumule, cotyledon and radicle
(d) radicle, cotyledon and plumule
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 ________.
Find the odd-one out, giving reason:
Anther, pollen grain, ovule male gamete
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
Identify the odd. Stigma, Style, Pollen, Ovary.
Mention pollination types.
Differentiate between self-pollination and cross-pollination.
What is cleistogamy? Write one advantage and one disadvantage of it, to the plant.
Find the odd one out:
Find an odd one out.
Calyx : Sepals : : Corolla : ________________
Pollen grains from anther are transferred to the stigma.
Match the following
| 1. | Petal | Opuntia |
| 2. | Fern | Chrysanthemum |
| 3. | Phylloclade | Attracts insect |
| 4. | Hooks | Spore |
| 5. | Sucker | Bignonia |
Write the events involved in the sexual reproduction of a flowering plant.
a. Discuss the first event and write the types.
b. Mention the advantages and the disadvantages of that event.
In which of the following manner the arrangement of megaspores in a tetrad is observed in angiosperms?
The ovule of an angiosperm is technically equivalent to ______
How many middle layers are generally present in the wall of the anther lobes?
What would be the number of chromosomes of the aleurone cells of a plant with 42 chromosomes in its roots tip cells?
Gloriosa superba exhibits ______.
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
In a plant flower the female whorl is ______.
Consider the following three flowers namely X, Y and Z. Which flower(s) would develop into a fruit?
| Flower X | Flower Y | Flower Z |
 |
 |
 |
Explain the post fertilization changes that occur in the ovary of a flower.
- Assertion: Primary endosperm nucleus is diploid.
- Reason: It is the product of double fertilisation.
