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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, resulting in the formation of an embryo; hence, seeds do not form in incompatible species.
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संबंधित प्रश्न
Geitonogamous flowering plants are genetically autogamous but functionally cross-pollinated. Justify.
A flower of tomato plant following the process of sexual reproduction produces 200 viable seeds.
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 ?
Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.
What are chasmogamous flowers?
Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
Fill in the blank:
Male sex cells in plants are called _________.
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.
Name of the parts of the ovary which give rise to:
Fruit wall ______
Describe the advantages and disadvantages of cross-pollination to the plant.
State four features of flowers pollinated by insects.
Answer the following question.
Express the process of pollination in Vallisneria.
Answer the following question.
Write the difference in the characteristics of the progeny produced as a result of the two processes.
Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi? Provide explanations to your answer.
Name the two types of pollination.
What is a flower? Draw a typical flower and label its different parts.
Describe pollination. How many types of pollinations are found?
The question has four options. Choose the correct answer:
Pollination by insect is known as
Which of the following pair has haploid structures?
In some plants anther and stigma mature at the same time this condition is called ______.
Which of the following plant contain unisexual flower?
Insect pollinated flowers are ______.
Which type of flower has ovary superior?
The flower which does not open at all are called ______.
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 ______.
The term used for transfer of pollen grains from anthers of one plant to stigma of a different plant which, during pollination, brings genetically different types of pollen grains to stigma, is ______
Choose the correct statement from the following:
Pollination in water lilies is carried out by ______.
What are the major abiotic factors that influence habitat?
