Question

Which of the following statements describe double fertilisation in flowering plants?

• A. An event in which two zygotes are formed in a single embryo sac.
• B. Fusion of the egg cell with one male gamete and fusion of polar nuclei with one male gamete.
• C. Fusion of the synergids with male gametes.
• D. An event in which there is fusion of two diploid gametes.

Answer 1

The correct option is B Fusion of the egg cell with one male gamete and fusion of polar nuclei with one male gamete.

Double fertilisation is unique to flowering plants. It is called double fertilisation because there are two types of fusion that occur within the embryo sac (syngamy and triple fusion).

In flowering plants, two male gametes are formed inside each pollen grain. These are carried to the embryo sac through pollen tube.

One haploid male gamete fuses with the haploid female gamete (egg cell) to form the diploid zygote. This fusion is called syngamy.

Another male gamete fuses with the two polar nuclei to form the primary endosperm nucleus (PEN). This is called triple fusion.

As there are two types of fusion, one is syngamy and another one is triple fusion, this phenomenon is termed as double fertilisation.