SEXUAL REPRODUCTION IN FLOWERING PLANTS: Solved Worksheet 3
1. Give an example of plant that came to India as contaminant and is a cause of pollen allergy.
Ans: Parthenium or Carrot Grass.
2. State the function of filiform apparatus found in mature embryo sac of an angiosperm.
Ans: Filiform apparatus helps to guide the path of pollen tubes into synergid.
3. How many microsporangia are present in a typical anther of angiosperm.
Ans: Usually Four.
4. Mention the ploidy of the different types of cells present in the female gametophyte of an angiosperm.
Ans:
Synergids = n (haploid)
Egg = n (haploid)
Polar nuclei = n(haploid)
Antipodals = n(haploid)
All type of cell of female gametophyte are = n (diploid).
5. Why do cleistogamous flowers assure seed sets?
Ans: Cleistogamous flowers are invariably autogamous as there is no chance of cross pollination.
6. Write one advantage and one disadvantage of cleistogamy to flowering plants.
Ans:
Advantage: Assured seed set/maintain purelines.
Disadvantage: No variation/only parental characters are preserved/it can lead to inbreeding depression.
7. How many pollen grains and ovules are likely to be formed in the anther and ovary of an angiosperm bearing 25 microspore mother cells and 25 megaspore mother cells respectively.
Ans: 100 pollen grains and 25 ovules.
8. What is the mode of pollination in Vallisneria and water lily.
Ans: Mode of pollination: Water(Hydrophily).
9. What are benefits of choosing a dioecious plant species for plant breeding experiments?
Ans: Unisexual: Self pollination avoided, Emasculation not required.
10. How would you proceed to cross-pollinate a monoecious flower?
Ans: By following method:
(a) Emasculation
(b) Bagging
(c) Pollination by spraying desired pollen.
(d) Rebagging.
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