Tag: cross pollination
Questions Related to cross pollination
Above ground cleistogamous flowers are formed late in the season in
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Balsam
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Viola
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Oxalis
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All the above
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No pollination agent is required
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It assures heterozygosity
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It allows xenogamy
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It favours insect pollination
Both autogamy and geitonogamy cannot occur in
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Papaya
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Cucumber
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Castor
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Maize
Match the columns and choose the correct combination.
| I | II | ||
|---|---|---|---|
| (a) | Cleistogamy | (m) | Insect pollination |
| (b) | Geitonogamy | (n) | Bud pollination |
| (c) | Entomophily | (o) | Pollination between flower of the same plant |
| (d) | Xenogamy | (p) | Wind pollination |
| (q) | Cross pollination |
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a-m, b-q, c-n, d-o
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a-n, b-o, c-m, d-q
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a-q, b-p, c-o, d-n
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a-o, b-m, c-q, d-n
Which one of the following is one of the characteristics of self-pollinated flowers ?
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Flowers are large and showy
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Flowers remain closed and do not open
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Stigma and anthers mature at the same time
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Pollen is produced in very large quantities
Self-pollinated flowers remain closed and don't open allowing maximum time for the mature stamens and pistils to exchange and receive the gametes.
Which of the following features are mostly observed in self pollinating flowers?
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Inconspicuous flowers
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Presence of nectaries
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No fragrance
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Short style
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Versatile anthers
The inconspicuous flower is a flower that is small, not showy and difficult to see. They are observed in self-pollinating flowers.
Which of the following statement is NOT correct?
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Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil.
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Some reptiles have have also been reported as pollinators in some plant species.
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Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style.
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Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers.
Pollen grains of other species are not compactable and do not germinate on the stigma of the flower of different species.
Select the mismatched pair.
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Storage of pollen grains - $196^o$C
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Pollen allergy - Carrot grass
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Chasmogamous flowers - Exposed anthers and stigmas
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Xenogamy - Self pollination
Xenogamy or cross pollination is the transfer of pollen grains from the anther of one flower to the stigma of a genetically different flower. Cross pollination is performed with the help of an external agency.
Even in absence of pollinating agents seed-setting is assured in.
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Commelina
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Zostera
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Salvia
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Fig
Commelina bears aerial, chasmogamous (stigma and anthers exposed to pollinating agents), insect pollinated flowers and underground cleistogamous flowers. Cleistogamous flowers are bisexual flowers which never open. In such flowers, the anther and stigma lie very close to each other. When anther dehisce in the flower buds, pollen grains come in contact with the stigma of the same flower i.e, autogamy occurs. So, these flowers produce assured seed set, even in the absence of pollinators.
How can plants prevent self pollination?
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Stamen and pistil mature at different times.
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Plants should develop bisexual flowers.
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Pistil should have increased receptivity for pollens from same plant.
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All of the above.
- There are several methods to prevent self-pollination in plants. Bisexual flowers show self-pollination.
- Chances of self-pollination increases when pistil has increased receptivity for pollen from the same plant. Self-pollination occurs in flowers where the stamen and carpel mature at the same time.
- Hence, to prevent self-pollination, stamen and pistil must mature at different times.