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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
As a senior biology student you have been asked to demonstrate to the students of secondary level in your school, the procedure(s) that shall ensure cross-pollination in a hermaphrodite flower. List the different steps that you would suggest and provide reasons for each one of them.
Describe the characteristic features of wind pollinated flowers.
Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.
Why angiosperm anthers are called dithecous?
What are chasmogamous flowers?
Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
Write two ways in which pollination may occur in plants.
Give one word/term for the following:
Pollination of flowers by birds.
Describe the advantages and disadvantages of cross-pollination to the plant.
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 ______.
Give four adaptations shown by flowers pollinated by wind.
Write different modes of pollination in detail with suitable examples.
What are the adaptations which are required in cross-pollinated
Give an account of any two biotic agents for pollination along with their adaptations.
For which of the following attractants and rewards are required?
Choose the correct statement from the following.
Wind pollination is common in ______.
Pollination by water occurs in ______.
Male and female flowers are present on different plants (dioecious) to ensure xenogamy, in ______.
The flower which does not open at all are called ______.
Give any four floral adaptations for chiropterophily.
Name the following:
Aquatic plants which are anemophilous.
Briefly discuss any two methods by which plants avoid self-pollination.
Identify the set of correct statements:
- The flowers of Vallisneria are colourful and produce nectar.
- The flowers of waterlily are not pollinated by water.
- In most of water-pollinated species, the pollen grains are protected from wetting.
- Pollen grains of some hydrophytes are long and ribbon like.
- In some hydrophytes, the pollen grains are carried passively inside water.
Choose the correct answer from the options given below:
Anemophily is the process of pollination by which agent?
Which plant is an example of ornithophily?
Which of the following agencies of pollination is abiotic in nature?
