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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?
Explain the post-pollination events leading to seed production in angiosperms.
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Answer the following questions giving reasons :
(a) What would have been the minimum number of ovules present in pre-pollinated pistil ?
(b) How many microscope mother cells would minimally be required to produce requisite number of pollen grains ?
(c) How many pollen grains must have minimally pollinated the carple ?
(d) How many male gametes would have used to produce these 200 viable seeds ?
(e) How many megaspore mother cells were required in this process ?
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Name of the part of the ovary which gives rise to:
Fruit ______
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Mention various adaptations for wind pollination.
A dioecious flowering plant prevents both ______.
Chief pollinators of agricultural crops are ______.
Anemophily type of pollination is found in ______.
Feathery stigma occurs in ______.
Plants with ovaries having only one or a few ovules are generally pollinated by ______.
Which of the following is not a water pollinated plant?
A botanist studying Viola (common pansy) noticed that one of the two flower types withered and developed no further due to some unfavorable condition, but the other flower type on the same plant survived and it resulted in an assured seed set. Which of the following will be correct?
Pollination refers to the ______.
Advantage of cleistogamy is:
Correct definition of pollination is ______
Pollination in water lilies is carried out by ______.
Mention any one example of the anemophilous flower.
Mention any one example of the hydrophilous flower.
Name the pollinating agent of a flowering plant with large and coloured flowers with sticky stigma. State one characteristic feature of the pollen grains produced in such flowers.
Bird pollinated flowers are usually ______.
