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प्रश्न
Give reason for the following:
Fertilization cannot take place in flowers if pollination does not occur.
Why cannot fertilization take place in flowers if pollination does not occur?
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उत्तर
In flowering plants, male gametes are produced in the pollen grains inside the anther. Pollination brings the pollen grains having male gametes from the anther to the stigma. Upon successful arrival of pollen grains on the stigma, a pollen tube is formed where they take male gamete to the female gamete or egg present in the ovule for fertilisation. So, if pollination does not occur, fertilisation will also not take place.
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संबंधित प्रश्न
Name and differentiate between the two modes of pollination in flowering plants.
Explain what you understand by sexual reproduction.
Fill in the following blank with suitable word :
Flowering plants reproduce by ...........method of reproduction.
Draw a neat sketch of the carpel of a flower. Mark in it stigma, style and ovary.
(a) Draw a neat diagram of a flower showing its various parts. In this diagram mark stem, receptacle, sepals, petals, stamen and carpel.
(b) What name is given to (i) all the petals of a flower, and (ii) all the sepals of a flower?
(c) What are (i) stamen, and (ii) carpel, in a flower?
(d) What is the other name of carpel of a flower?
(e) What is the name of yellow powdery substance present in the anther of a flower?
One of the following occurs in the reproductive system of flowering plants as well as that of humans. This is :
(a) vas deferens
(b) anther
(c) ovary
(d) style
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)
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?
Fill in the blanks:
A carpel consists of ________ , ________ and ________.
Fill in the blanks:
A stamen consists of ______ and ________.
State whether the following statement is true (T) or false (F):
Flowers which possess stamens and carpel are called unisexual.
Draw a labelled diagram of a bisexual flower.
Prepare a slogan for campaign against female foeticide.
__________ is present in unisexual flower.
Which of the following are the chemical components of the wall of pollen tube?
Gloriosa superba exhibits ______.
The process of release of eggs from the ovary is called ______
In human beings, fertilization occurs in the ______
What is the structural unit of sexual reproduction in plant?
Given below is a diagram of a germinating seed. Label the parts that:
- gives rise to future shoot.
- gives rise to future root system.
- stores food.
