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प्रश्न
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.
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उत्तर
The pollen particle receives water and nutrients after touching a suitable stigma. It creates a tube known as a pollen tube. Pollen tube develops in the style and travels to the ovary. Two male gametes, or sperm cells, and a tube nucleus may be found at its tip. The advancing pollen tube penetrates the inside of the embryo sac of an ovule, often through the micropyle. The tube ruptures at this point, releasing its two male gametes. To create a zygote, one male gamete unites with one egg.
The action is referred to as syngamy. Endosperm is created when the second male gamete combines with binucleate central cells. Triple fusion is the name given to the process since it includes the fusing of three haploid nuclei. Accordingly, triple fusion is the union of a male gamete with two polar nuclei inside the angiosperm's embryo sac.
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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 ______.
| When an insect sits on the flower of a plant then somene 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. |
- 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?
- What is the name of tube B?
- What is C which moves down through the tube B?
- Name D and E.
- What is F?
List any two differences between pollination and fertilization.
Fill in the blank by selecting suitable word:
Transfer of pollen grains from the anther to the stigma is known as______________.
Identify the female gametophyte in angiosperms.
In a flowering plant, archesporium gives rise to ______.
Sketch and label the essential and accessory whorls of flower.
Name the reproductive parts of an angiosperm. Where are these parts located? Explain the structure of its male reproductive part.
- Assertion: Primary endosperm nucleus is diploid.
- Reason: It is the product of double fertilisation.
