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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
How does fertilisation occur in flowers? Name the parts of the flower that develop into (i) seed, and (ii) fruit after fertilisation.
Name the parts A, B and C shown in the following diagram and state one function of each.
A student has to perform the experiment "To identify the different parts of an embryo of a dicot seed." Select from the following an appropriate group of seeds:
(a) Pea, gram, wheat
(b) Red kidney bean, maize, gram
(c) Maize, wheat, red kidney bean
(d) Red kidney bean, pea, gram
Mention the changes a flower undergoes after fertilisation.
Write the names of those parts of a flower which serve the same function as the following do in the animals :
(i) testis,
(ii) sperm,
(iii) ovary,
(iv) egg
What is made in anther 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)
The part of a seed which grows and develops into root on germination is :
(a) cotyledon
(b) plumule
(c) follicle
(d) radicle
Fill in the blanks:
A carpel consists of ________ , ________ and ________.
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
Write the names of male and female reproductive parts of a flower.
Prepare a slogan for campaign against female foeticide.
Answer the following question.
How does suitable pollination lead to fertilization?
A student is observing the temporary mount of a leaf peel under a microscope. Draw a labelled diagram of the structure of stomata as seen under the microscope
Answer the following question.
List two agents of pollination?
Find the odd one out:
Accessory whorls : Calyx and corolla : : essential whorls : ______________
Observe the figure below. Write functions of the labelled parts.
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.
Antipodal cells are present towards the ______ in an anatropous ovule.
Which of the following is the outermost protective layer of anther?
How many middle layers are generally present in the wall of the anther lobes?
The 3-celled egg apparatus at the micropylar end comprises of ______
Identify the female gametophyte in angiosperms.
Pineapple fruit develops from ______.
The process of release of eggs from the ovary is called ______
In human beings, fertilization occurs in the ______
Which among the following statements are true for unisexual flowers?
- They possess both stamen and pistil
- They possess either stamen or pistil
- They exhibit cross pollination
- Unisexual flowers possessing only stamens cannot produce fruits
Is the chromosome number of zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
What is the structural unit of sexual reproduction in plant?
Sexual maturation of reproductive tissues and organs are necessary link for reproduction. Elucidate.
The pollen tube usually enters the embryo sac ______.
