Question

Explain the process of fertilisation in plants.

Answer 1

• Fertilization is the process of union of male and female gametes. In plants, pollination takes place. There are 4 steps of fertilization, namely pollination, germination, penetration into the ovule and fertilization. During pollination, pollen grains reach the surface of the stigma.
• Pollen grains then germinate into pollen tubes. Only one pollen tube reaches the embryosac. The pollen tube has two male nuclei, which migrate to the tip of the pollen tube. The pollen tube penetrates the ovule through the micropyle and two male gametes are then released into it.
• One gamete fertilizes with the egg and forms a diploid (2n) zygote. This is the first fertilization. The other gamete combines with diploid (2n) secondary nucleus (2n) to form triploid (3n) endosperm.
• This is the second fertilization in the embryosac. This double fertilization is seen in angiosperms. After fertilization, the zygote divides and develops into an embryo or developing the plant.