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प्रश्न
List the different types of pollination depending upon the source of pollen gain.
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उत्तर
Pollination is the process of transfer of pollen grains from anther to stigma.
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Depending on the source of pollen grains, pollination can be divided as follows:
- Autogamy - It is the transfer of pollen grains from anther to stigma of the same flower. Autogamy requires the anther and the stigma to lie close. It also requires synchrony in the pollen release and stigma receptivity. Plants like Viola and Oxalis produce two kinds of flowers: chasmogamous flowers (with exposed anther and stigma) and cleistogamous flowers (plants that do not open at all and in which only autogamy occurs).
- Geitonogamy - It is the transfer of pollen grains from the anther of one flower to the stigma of another flower in the same plant. Genetically, it is similar to autogamy, but it requires pollinating agents.
- Xenogamy - It is the transfer of pollen grains from the anther to the stigma of a different plant. Pollination causes genetically different pollen types to be brought to a plant.
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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 240 viable seeds.
Answer the following questions giving reasons :
(a) What is the minimum number of pollen grains that must have been involved in the pollination of its pistil?
(b) What would have been the minimum number of ovules present in the ovary?
(c) How many megaspore mother cells were involved?
(d) What is the minimum number of microspore mother cells involved in the above case?
(e) How many male gametes were involved in this case?
Mention two strategies that evolved to prevent self-pollination in flowers.
When maturation time of reproductive parts in a flower is different.
State four features of flowers pollinated by insects.
From among the situations given below, choose the one that prevents both autogamy and geitonogamy.
Pollination by water occurs in ______.
Feathery stigma occurs in ______.
In which one of the following pollination is autogamous?
Autogamy can occur in a chasmogamous flower if ______.
