Explain why sexual reproduction in angiosperms is said to take place through double fertilization and triple fusion. Also draw a labelled diagram of embryo sac to explain the phenomena.
The polar cell contains 2 nuclei.
Double fertilization:
• It is the phenomenon in which when a pollen reaches the stigma of the female flower, it germinates to produce 2 male nuclei and a vegetative cell.
• The 2 male nuclei enters the embryo sac, one of the male gamete fuses with egg to form a diploid zygote & the other male gamete fuses with diploid secondary nucleus to form triploid primary endosperm nucleus (PEN).
• Hence, because of the two fusions this phenomenon is called double fertilization.
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