Question

Which of the following is an exclusive feature of angiosperms?

• A. Double fertilisation
• B. Triploid endosperm
• C. Presence of vessels in xylem
• D. Both $1$ and $2$

Answer 1

Answer: (D)

Double fertilisation and formation of triploid endosperm are the exclusive features of angiosperms. Double fertilisation is the fusion of two male gametes brought by a pollen tube to two different cells of the same female gametophyte in order to produce two different structures. In angiosperms the pollen tube bursts open in one of the two synergids to release the two male gametes. One male gamete fuses with the egg or oosphere to form a diploid zygote or oospore (generative fertilisation). The second male gamete descends down and fuses with the diploid secondary nucleus of the central cell to form a triploid primary endosperm cell (vegetative fertilisation).