When pollen lands on stigma, it germinates and gives rise to a pollen tube that passes through the style and reaches the ovary of a pistil. When the pollen tube reaches an ovule, it releases the male gametes. A male gamete fuses with a female gamete in the ovule. This process is known as fertilisation. The cell which is formed after the fusion of a male and a female gamete is known as zygote. This zygote divides several times in order to form the embryo present inside the seed.

Fertilization in Flowers

Fertilization is a crucial process in the reproductive cycle of flowering plants. It involves the fusion of male and female gametes to form a zygote, which eventually develops into an embryo. Let's explore the detailed process of fertilization in flowers.

1. Pollination:
Pollination is the first step in the process of fertilization. It can occur through various mechanisms, including self-pollination (transfer of pollen within the same flower) or cross-pollination (transfer of pollen between different flowers). Pollen grains, containing the male gametes, are produced in the anthers of the flower. They are released and then transported to the stigma, which is part of the female reproductive structure.

2. Germination of Pollen:
Once the pollen grains land on the stigma, they must germinate to initiate fertilization. This process involves the growth of a pollen tube from the pollen grain. The pollen tube grows through the style, a long tube-like structure that connects the stigma to the ovary.

3. Double Fertilization:
Double fertilization is a unique characteristic of flowering plants. It involves the fusion of two gametes from the male pollen tube with two different female gametes. The two female gametes are located within the ovule, which is present in the ovary.

- Fertilization of the Egg Cell: One of the male gametes fuses with the egg cell, resulting in the formation of a zygote. The zygote is the beginning of the new plant embryo.

- Fertilization of the Central Cell: The other male gamete fuses with the central cell, which contains two polar nuclei. This fusion forms a triploid cell, which develops into the endosperm. The endosperm serves as a nutrient source for the developing embryo.

4. Embryo Development:
After fertilization, the zygote undergoes cell division and differentiation, leading to the development of an embryo. It develops within the ovule, which later becomes the seed. The endosperm also undergoes cell division and forms a nutritive tissue that supports the growing embryo.

5. Seed Formation:
As the embryo develops, other structures of the flower, such as the petals and sepals, wither and fall off. The ovary matures and becomes a fruit, enclosing the developing seeds. The seeds contain the embryo and are dispersed by various means, such as wind, water, or animals.

In conclusion, the process of fertilization in flowers involves pollination, germination of pollen, double fertilization, embryo development, and seed formation. This intricate process ensures the successful reproduction of flowering plants and the production of new generations.