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प्रश्न
Give scientific reason.
Fertilization in plants is called double fertilization.
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
Name the parts labelled as A, B, C and D in the diagram given below:-
Answer the following question.
What is pollination? Explain the different types of pollination.
(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?
Name the parts labelled as A, B, C and D in the diagram given below:
Mature ovary forms the ______.
State the name of the functional unit concerned with sexual reproduction.
Where are the pollen grains produced?
Fill in the following blank with suitable word :
Pollen grains contain ............ gametes of a plant.
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...........
Fill in the following blank with suitable word :
The name of the structure in the flower in which the male gamete is formed is...........
Give some examples of different modes of fertilisation in nature?
Name the part of a seed which contains stored food.
The correct sequence of reproductive stages occurring in flowering plants is ______
When an insect sits on the flower of a plant then some particles A present in the top of little stalks in the flower attach to its body hair. When this insect now sits on the flower of another similar plant, then particles A attached to the hair of insect are put on the top of a flask-shaped organ at the centre of flower. The particle A grows a long tube b from the top of flask-shaped organ through which C moves down and reaches the bottom part of flask-shaped organ. Here C fuses with the nucleus of d contained in structure E. the fusion of C and D forms a new cell f which grows and develops into a seed of the plant.
(a) What are particles A? What is the process of transferring A from one flower to another flower of similar plant by the insect known as?
(b) What is the name of tube B?
(c) What is C which moves down through the tube B?
(d) Name D and E.
(e) What is F?
State whether the following statement is true (T) or false (F):
Stamens make egg cells.
What are the male and female gametes in a flowering plant?
Sketch the labeled diagram:
Flower with its sexual reproductive organs
Fill in the blank by selecting suitable word:
Transfer of pollen grains from the anther to the stigma is known as______________.
What is cleistogamy? Write one advantage and one disadvantage of it, to the plant.
Find an odd one out.
Calyx : Sepals : : Corolla : ________________
Pollen grains from anther are transferred to the stigma.
Define.
Inflorescence
What does germination mean?
Draw a neat and labelled diagram.
Double fertilization in angiosperms
The male reproductive part of a flower is ______.
Identify the parts A, B, C, and D?
Generally, in a pollen tube, which of the following moves to the tip of the tube?
In a flowering plant, archesporium gives rise to ______.
The flower of the Hibiscus plant is ______
The process of release of eggs from the ovary is called ______
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
What is the function of calyx?
Sexual maturation of reproductive tissues and organs are necessary link for reproduction. Elucidate.
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 ______.
