6.3 - Pollination and Fertilisation

Pollination refers to the process of transferring pollen grains from anther to stigma. This process is facilitated by pollinating agents such as insects, mammals, birds, water and wind. The presence of pollen grain at the stigma will lead to the process of fertilization.

Figure 5 - Pollinating agents such as bees and birds help the spread of the pollen grains from one place to another.

Double Fertilisation in the Formation of Diploid Zygote and Triploid Nucleus

Double fertilization refers to the process of fertilization of two male gametes, where the first male gamete will fertilise the egg cell to produce a diploid zygote whereas the second male gamete will fuse with the polar nuclei to form a triploid endosperm tissue.

Importance of Double Fertilisation for the Survival of Flowering Plants

• The fertilization of one male gamete with egg cell forms a diploid zygote.
  • This ensures the continuous inheritance of genetic information.
  • Restore the haploid condition in gametes through formation of a diploid zygote.
• The fusion of the other male gamete with two polar nuclei forms endosperm tissues.
  • Endosperm tissues are used for the development of embryo to ensure survival of the species.
  • Endosperm tissues are fully utilized by eudicots such as legumes, mangoes and mustard before the embryo matures.
  • However, only part of the endosperm tissues will be used for the development of monocots such as coconut, wheat, barley and corn. The other part will be stored in the cotyledon for the germination of the seeds.
  • Endosperm tissues help the embryo to survive in the seed for a long period of time when the condition is less suitable for germination process.