Prcise
0.2 Very short answer type questions :
1. Name the part of gynoecium that
determines the compatible nature of
pollen grain.
2. How many haploid cells are present in a
mature embryo sac?
3. Even though each pollen grain has 2
male gametes, why atleast 20 pollen
grains are required to fertilize 20 ovules
in a particular carpel?
4. Define megasporogenesis.
5. What is hydrophily?
6. Name the layer which
which supplies
nourishment to the developing pollen
grains.
Answers
Answer:
1) Stigma of carpel/ pistil
2) 6 haploid cells and 2 nucleic cells
3) Even though 2 male gametes are there in one pollen grain, 10 pollen grains are required to fertilise 10 ovules. This is due to the presence of double fertilization in angiosperms. The other male gamete fuses with the polar nuclei and forms the primary endosperm nucleus (PEN).
4) Megasporogenesis refers to the development of megaspores from the megasporocyte, the cell that undergoes meiosis.
5)Hydrophily is a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams.
6) Tapetum is the innermost layer of the microsporangium. It provides nourishment to the developing pollen grains.
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