what is pollination?

Pollination is the process of depositing matured pollen from one flower on the stigma of another flower of the same species. Pollination takes place in two ways.

• Self-pollination
• Cross-pollination

Pollination process diagram

Self-pollination

Self-pollination is the process of depositing matured pollen from a flower on the stigma of the same flower.

Cross – pollination definition

Cross-pollination permits the blending of characteristics between two plants. It contributes to the creation of a new generation with unique characteristics.

Parts of a flower

Pollination of flowering plants

Why is cross-pollination important?

Cross-pollination allows the characteristics of two plants to be combined. It contributes to the formation of a strong new generation with distinct characteristics.

Pollen is transferred from one flower of the same species to another flower of the same species through a process known as cross-pollination. It is important for several reasons:

Genetic diversity:

Cross-pollination can increase genetic diversity within plant populations, allowing them to adapt and evolve in response to changing environmental conditions. This is important for plant species grown for food because increased genetic diversity can improve crop yields and resistance to pests and diseases.

Improved plant health:

Cross-pollination can help reduce the incidence of inbreeding, which can lead to weakened, less healthy plant populations. This is because inbreeding can increase the likelihood of harmful genetic mutations and decrease the expression of beneficial traits.

Increased biodiversity:

Because it allows different plant species to interact and exchange genetic material, cross-pollination can help promote greater biodiversity within plant communities. This is important for maintaining healthy ecosystems because increased biodiversity can support a diverse range of plant and animal species.

Seed production:

Cross-pollination is essential for the production of certain types of seeds, such as hybrid seeds, which are often used in agriculture to produce crops with specific desired traits.

Adaptations to avoid self-pollination and promote cross-pollination

Show Self – Sterility

Fruits are not developed when pollen of a flower is deposited on the stigma of the same flower.

Hercogamy

This is the distant placement of a flower’s stamens and stigma.

Having extrose stamens

The stigma is straight while the stamens are bent to the side, or the stamens are straight while the stigma is bent to the side.

Dichogamy

The stamens mature before the pistil (proterandry), or the pistil matures before the stamens (protogyny).

Having unisexual flowers

Pistillate flowers and staminate flowers borne on separate plants at the same time.

Pollination agents

Factors that contribute the pollination of flowers are known as agents of pollination. There are three principal agents of pollination.

1.Animals

2.Wind

3.Water

Animals

Animal pollinated flowers are known as zoophilous flowers. Insects are important pollinators among animals. Flowers have adaptations that attract insects for pollination.

• Having colourful flowers and being of a considerable size.
• Flowers that emit a scented aroma.
• Having nectariferous glands
• Pollen being sticky.
• Stigma being sticky.
• Flowers with shapes that are deceptive to insects and other pollinators.
• Both the stamens and the stigma are situated in such a way that it is simple for animals to make contact with them.

Wind

Wind pollinated flowers are known as aerophilous or anemophilous flowers. These flowers are usually found as staminate and pistilate flowers. Aerophilous flowers have the following pollination adaptations.

• Pollen grains are extremely small and light.
• Flowers are born at the plant’s apex.
• Inflorescences contain flowers.
• A significant amount of pollen is produced.
• Stigma is divided into branches.

Water

The flowers that are pollinated by water are called hydrophilous flowers. These flowers are usually found as staminate and pistilate flowers. Some of the adaptations of hydrophilous flowers for pollination include:

Lack of petals:

Many hydrophilous flowers have reduced or absent petals, which are not necessary for pollination in a water environment. Instead, these flowers rely on the flow of water to carry pollen from the male to the female parts of the flower.

Long stamens and styles:

Hydrophilous flowers have elongated stamens and styles that extend out of the flower and into the water, where they can be pollinated by water.

Flotation devices:

Some hydrophilous flowers have adaptations that allow them to float on the surface of the water, making them more visible to pollinators such as water beetles and flies.

Scent production:

Even in the absence of petals or other showy flower parts, some hydrophilous flowers emit strong scents that can attract pollinators.

Pollen release timing:

Hydrophilous flowers often release their pollen at specific times when water currents are strong, such as during flood events, to increase the chances of successful pollination.