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प्रश्न
Why does self-pollination not lead to seed formation in self-incompatible species?
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उत्तर
Self-incompatibility is a gene-physiological event. A single gene, known as the S-gene, regulates incompatibility reactions and contains many alleles. Pollen grains with the S-allele, which is shared by either of the two alleles in pistil cells, won’t work on that pistil. However, any pollen grain that does not share S-alleles with the pistil will function on that plant’s pistil. Self-pollens are unable to fertilize the egg, preventing the formation of an embryo; hence, seeds do not form in self-incompatible species.
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संबंधित प्रश्न
Why do moss plants produce very large number of male gametes? Provide one reason. What are these gametes called?
Describe the characteristic features of wind pollinated flowers.
Give the floral adaptations for anemophily.
Write two ways in which pollination may occur in plants.
Find the odd-one out, giving reason:
Ovary, style, pollen grain, stigma
Complete the following chart and rewrite.
| Sr.No. | Agencies | type of pollination |
| 1 | Water | .................... |
| 2 | ........................... | Entomophily |
| 3 | Bat | .................... |
| 4 | ....................... | Ornithophily |
(Or)
Explain outbreeding devices in angiospermic plants.
Compare the characteristic features of insect pollinated and wind pollinated flowers. Explain how the respective features assist in pollination.
State the name of the chief pollinating agent against the corresponding plant by choosing from those given in brackets.
Dahlia_______ .
In bisexual flowers, maturation of gynoecium before androecium is known as ______.
Type of interaction where an individual sacrifices its own welfare (life) for the benefit of another animal of its own species is ______.
Differentiate between geitonogamy and xenogamy (allogamy).
Put a tick mark (✓) against the correct alternative in the following statements
Pollen is produced in the
Describe the Advantages and Disadvantages of self-pollination to the Plant.
What are the different adaptations shown by bird-pollinated flowers?
Explain water pollination in detail with its types.
Give an account of various abiotic agencies used in pollination along with their adaptations for pollination.
For which of the following attractants and rewards are required?
Plants with ovaries having only one or a few ovules are generally pollinated by ______.
Which of these is a condition that makes flowers invariably autogamous?
In the dioecious aquatic plant shown, identify the characteristics of the male flowers that reach the female flowers for pollination:
| Size of the flower | Colour of flower | The characteristic feature of pollen grain | |
| A | small | brightly coloured | Lightweight and non-sticky |
| B | large | colourless | large and sticky |
| C | small | white | small, covered with mucilage |
| D | large | colourless | non-sticky |
Advantage of cleistogamy is:
In which one of the following pollination is autogamous?
Choose the correct statement from the following:
Consider the following statements depicting adaptation of flowers to carryout successful pollination.
- Stigma is long, sticky and unwettable.
- Sepals, petals or perianth (if present) have waxy coating.
- Stamens with long filament and versatile anthers.
- Tubular corolla is seen.
- Flowers are noctumal.
Which of the above statements clearly depict hydrophily?
Give any four floral adaptations for chiropterophily.
In sea grass, pollens are long, ribbon like and without exine exhibiting ______ pollination.
