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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
Name the parts A, B and C shown in the diagram and write their functions.
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
Name and differentiate between the two modes of pollination in flowering plants.
Give one example of a unisexual flower.
A flower may have either male or female reproductive parts. Such a flower is called ______.
The fusion of male and female gametes is termed as ______.
Name the swollen lower part of the carpel.
Name the male part of the flower.
Where are a plant's sex organs located?
Where is the male gamete formed in flowering plants?
Fill in the following blank with suitable word :
The name of the structure in the flower in which the male gamete is formed is...........
Fill in the following blank with suitable word :
The.......... at the base of the carpel contains egg cells.
Fill in the following blank with suitable word :
The term used to refer to the transfer of pollen from the stamen of one flower to the carpel of another flower of the same species is...........
What is made in ovary of a flower?
Describe the process of fertilisation in a flower with the help of labelled diagrams.
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)
In what ways is fertilisation in a plant similar to fertilisation in a human?
Mention the function of Anther.
What part is played by stamens and carpels in reproduction?
The students of a class were asked by the teacher to study the different parts of an embryo of an angiosperm. Given below are the essential steps for the experiment :
A. Soak the seeds in plain water and keep them overnight.
B. Cut open the soaked seed and observe its different parts.
C. Take some healthy seeds in a petri-dish.
D. Drain the excess water, cover the seeds with a wet cotton cloth and leave them as it is for a day.
The correct sequence of these steps is
(a) C, A, D, B
(b) C, D, A, B
(c) A, C, D, B
(d) A, C, B, D
Identify A, B, C and D in the given diagram and write their names.
A student is asked to study the different parts of an embryo of pea seeds. Given below are the essential steps for the experiment :
(I) Soak the pea seeds in plain water and keep them overnight.
(II) Cut open the soaked seed and observe its different parts.
(III) Take some pea seeds in a petri dish.
(IV) Drain the excess water. Cover the seeds with a wet cotton cloth and leave them as it is for a day.
The correct sequence of these steps is
(A) III, I, IV, II
(B) III, IV, I, II
(C) III, I, II, IV
(D) III, II, I, IV
Draw a diagram of a pistil showing pollen tube growth into the ovule and label the following:
Pollen grain, male gamete, female gamete, ovary.
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
Sketch the labelled diagram.
Flower with its sexual reproductive organs.
Fill in the blanks and rewrite the completed statements:
Lymph flows in _______________ direction.
Which type of development is observed in male gametophytes of plants?
Identify the female gametophyte in angiosperms.
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 ______.
Sperm and egg nuclei fuse due to ______.
Pineapple fruit develops from ______.
What would be the number of chromosomes in the cells of the aleurone layer in a plant species with 8 chromosomes in its synergids?
Complete the table
| Carly x | ______ | ______ |
| ______ | petal | attract insects |
| Androecium | ______ | Male reproductive part |
| ______ | ______ | Female reproductive part. |
Double fertilization is essential for formation of ______.
Type of sexual reproduction is ______.
Explain the post fertilization changes that occur in the ovary of a flower.
State the post-fertilisation changes that lead to fruit formation in plants.
