Reproduction in flowering plants — KCSE Biology

Pollination is the transfer of pollen grains from the anther to the stigma of a flower. It can occur through various agents, including wind, insects, and water. There are two main types of pollination:

• Self-pollination: Pollen from the anther fertilizes the ovule of the same flower.
• Cross-pollination: Pollen from one flower fertilizes the ovule of another flower, promoting genetic diversity.

Once pollination occurs, fertilisation takes place. This process involves the fusion of male gametes (sperm cells) from the pollen grain with the female gamete (ovule) in the ovary. The stages of fertilisation include:

1. Pollen germination: The pollen grain absorbs moisture and forms a pollen tube.
2. Growth of pollen tube: The pollen tube travels down the style to the ovule.
3. Fertilisation: The sperm cells move through the pollen tube and enter the ovule, where fertilisation occurs, forming a zygote.

This zygote eventually develops into a seed, while the ovary matures into a fruit, facilitating seed dispersal.

Flowering plants reproduce through a process called sexual reproduction, which involves the formation of seeds. The main structures involved are the stamens (male) and pistils (female).

1. Stamens: Composed of an anther and a filament. The anther produces pollen grains, which contain male gametes.
2. Pistils: Composed of the ovary, style, and stigma. The ovary contains ovules, which house the female gametes.

The process of reproduction includes the following steps:

• Pollination: Transfer of pollen from the anther to the stigma.
• Fertilization: Occurs when a male gamete unites with a female gamete in the ovule, forming a zygote.
• Seed Development: The fertilized ovule develops into a seed, while the ovary matures into a fruit.

This method ensures genetic variation, which is crucial for the adaptation and survival of species in changing environments.