with the labelled diagram show the process of fertilization in flowers.
Answers
Answer:
A shows a pollen grain which is germinating as pollen tube is emerging from it.
B shows stigma which is the part of flower on which pollen grain germinates.
C shows style which is the part of flower through which pollen tube travels and reaches the ovary.
D shows embryo sac which is a 7-celled 8-nucleate structure consisting of synergids, antipodal cells, egg cell and central cell (two polar nuclei).
4) This tube will have two male nuclei, which migrate to the tip of the pollen tube at the time of fertilization.
5) Usually the pollen tube enters the ovule through micropyle and discharges the two male gametes into its embryosac.
6) One male nucleus (gamete) approaches the egg and fuses with it to form a diploid (2n) zygote. This is first fertilization.
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nO +. nO ------> 2n ( zygote)
+
7) The other male nucleus (gamete) reaches the secondary nucleus (2n) and fuses with it to form endosperm nucleus which will be triploid. This is second fertilization in the embryosac.
8) Thus double fertilisation occurs in embryosac which is unique in flowering plants.
Hope this helps ✌✌✌
