Advertisements
Advertisements
Question
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?
Advertisements
Solution
(a) A represents pollen grains. The process of transferring pollen grains from one flower to another flower of the similar plant by insects is known as cross pollination.
(b) B represents the pollen tube.
(c) C is the male gamete which moves down through the pollen tube (B).
(d) D is the female gamete (or egg). The structure E represents the ovule.
(e) F is the zygote.
APPEARS IN
RELATED QUESTIONS
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
What is pollination?
"The chromosomal number of the sexually producing parents and their offspring is the same." Justify this statement.
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 name of the structure in the flower in which the male gamete is formed is...........
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...........
The flask-shaped organ A at the centre of a flower is surrounded by a number of little stalks B having swollen tops which lie just inside the ring of petals.
(a) Name A. What are the various parts of A?
(b) Which part of A contains gametes?
(c) Name B. What is the swollen top of B known as?
(d) What does the swollen top of b contain?
(e) Out of A and B, which one is (i) male part, and (ii) female part of the flower?
Put a tick mark (✓) against the correct alternative in the following statement
Reproductive whorls of a flower are:
Draw a labelled diagram of a bisexual flower.
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?
Calyx : Sepals : : Corolla : ________________
Draw a neat and labelled diagram.
Double fertilization in angiosperms
Generally, in a pollen tube, which of the following moves to the tip of the tube?
What would be the number of chromosomes in the cells of the aleurone layer in a plant species with 8 chromosomes in its synergids?
Conidia are formed endogenously while zoospores are formed endogenously.
Where is the zygote located in the flower after fertilization?
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.
- Assertion: Primary endosperm nucleus is diploid.
- Reason: It is the product of double fertilisation.
