Question
Describe the process of fertilization in flowering plants.
Answer
Fertilization is a process that occurs during sexual reproduction in flowering plants. The process of fertilization in flowering plants can be described as follows:
- Pollination: The process starts with the transfer of pollen from the anther of the stamen to the stigma of the pistil. Pollination can occur through wind, insects, birds, or other animals.
- Germination of pollen: Once the pollen grain lands on the stigma, it begins to germinate and grow a pollen tube down the style towards the ovary.
- Penetration of the ovule: The pollen tube penetrates the micropyle (a small pore) in the ovule, and the male gametes (sperm cells) move down the pollen tube towards the egg cell.
- Fertilization: Once the pollen tube reaches the egg cell, one of the sperm cells fuses with the egg cell to form a zygote. This zygote develops into an embryo, while the ovule develops into a seed.
- Formation of endosperm: The second sperm cell fuses with two polar nuclei in the ovule, forming a triploid cell that develops into the endosperm, which provides nutrients for the developing embryo.
- Seed development: The ovary of the flower develops into a fruit, which protects and disperses the seeds. The seed itself consists of the embryo, the endosperm, and a protective seed coat formed from the ovule’s integuments.
