A great variety of plants we consume as food or fruit depend on pollination to facilitate reproduction and regeneration. But what is pollination? How does it happen? Where does it occur, and what is its importance?
Plant reproduction relies on pollination, which is when a pollinator moves pollen from the anthers of a flower (male parts) to a flower’s stigma (female parts). This fertilizes the flower leading to seeds and fruits. The main pollinators are living (biotic) and non-living (abiotic).
What is pollination?
Pollination is the transfer of pollen from the anther of a flower to the stigma. This process of transfer enables fertilization to occur and results in the production of seeds and fruits.
Two types of pollination occur in plants, namely:
- Self-pollination occurs between flowers on the same plant, either within the same flower or between different flowers of the same plant.
- Cross-pollination occurs when pollen transfers from one plant’s flower to another plant of the same species.
Pollination is accomplished through abiotic agents such as wind and water. However, it’s effected by biotic agents such as birds and insects, among other organisms.
The relationship between plants and pollinators is mutualistic. Plants benefit from the transfer of pollen, while pollinators receive nutritional or other rewards.
Importance of pollination
The entire pollination process is vital to the functionality of the whole ecosystem. Here’s why:
- Pollination is considered a vital ecosystem service, specifically as a supporting or regulating service.
A supporting service maintains other ecosystem services, such as nutrient cycling. It also helps maintain the balance in ecosystems, such as erosion prevention or climate regulation.
- Pollination produces fruit, seeds, and plants for agriculture and animal feed.
- It also maintains and increases diversity within and between native species of plants that humans sometimes use for medicine, food, building, etc. As it increases the diversity within plant species, it potentially supports the emergence of new compounds that may be useful in food or medicine.
- A wide range of animals benefit from pollination. Plant reproduction results in animal species’ food and habitat, supporting the food chains and environment.
- Pollinators are crucial in maintaining indigenous flora and fauna. Many people value nature and its diversity for spiritual reasons, supported by pollinators.
- Many pollinating species also directly produce other products for human consumption, such as honey, wax, and propolis.
Without pollination, there won’t be new plants supporting the world as a whole.
Where does pollination occur?
Pollination all begins in flowers. Flowering plants have several different parts that are important in pollination.
Flowers have male parts called the stamen that produce a sticky powder called pollen and can be found on the top part of the anther.
Flowers also have a female part called the pistil; the top part of the pistil is called the stigma and is often sticky.
To be pollinated, pollen must be moved from the stamen and deposited on the stigma.
Once there, the pollen germinates and gives rise to a pollen tube which goes down through the pistil towards the ovules and fuses with the egg cell of the ovule.
This process fertilizes the egg cell and allows an embryo to develop.
What carries out pollination?
Pollination is achieved with the help of specific agents that facilitate pollen movement from the anther to the stigma.
These pollination agents can fall into two broad categories:
- Abiotic pollinators are non-living agents that plants may use to move pollen from one flower to another. Examples of these include water and wind.
- Biotic pollinators are living organisms that rely on flowers for one resource or another and work as pollinators moving pollen from one flower to another.
Further, the process of pollination is categorized into 4 other subcategories:
- Hydrophily. This is where water acts as the pollinating agent, as is common in aquatic plants. The pollen has to be buoyant for this to be achieved.
- Anemophily. This is where pollination is carried out with wind assistance, as observed in plants such as maize.
- Entomophily. This is where pollination is facilitated by insects attracted by huge, vividly colored flowers that emanate a perfume and produce nectar.
- Zoophily. This is where pollination happens with the help of animals.
Flowers with hairy pollen grains stick to the body of animals when they come into contact and transfer them to another plant when they move.
Animals as pollinators
Below we will discuss some of the main animals and insects that act as pollinators and their pollination methods.
1. Bees
Bees are good agents of pollination because of their instinct to gather nectar from flowers of one species at a time. They can recognize the flower of one species by its smell, general form, and color.
Bees are attracted to flowers that have a sweet smell, brightly colored petals (usually blue or yellow), and nectar.
They rub against the anthers as they move on the flowers, collecting nectar and, in the process, collecting pollen on their furry bodies and legs.
2. Butterflies and Moths
Both butterflies and moths have similar structures. They both have a long tube-like form called a proboscis, through which they feed on nectar.
They, however, differ in their feeding time. Butterflies are active and feed during the daytime, while moths are active and feed at dusk and night.
Butterflies and moths usually feed on different flowers. Butterflies feed on flowers characterized by brightly colored petals, while those fed on by moths are characterized by heavy fragrance.
Butterflies and moths collect pollen and disperse it as they perch and walk on flowers during their feeding process.
3. Flies
Some plants, such as the pongapong flower found in tropical countries such as the Philippines, are pollinated by flies.
Flowers that fly like this pollinate have pungent smells that mimic rotting flesh, attracting pollinators.
Flies pollinate flowers in the same way bees would in that they collect pollen on their hairy legs as they walk on the flowers in search of food.
4. Birds
These visit flowers to feed on their nectar, pollen, or the insects that live in them. Incidentally, they transfer pollen grains as they travel from flower to flower.
Birds have good vision but a poor sense of smell. As such, the flowers they pollinate are often characterized by large, brightly colored petals.
Examples of plants pollinated by birds include peas, pineapples, bananas, orchids, and cacti.
5. Bats
Bats such as the long-nosed bat feed on pollen from night-blooming flowers. Since they feed at night and can’t rely on sight to locate their food, the flowers they feed on are characterized by sweet smells.
Examples of flowers pollinated by bats include the areca palm, candle tree, and durian.
How to help pollinators
Pollinators do irreplaceable critical work. Therefore, it is necessary to safeguard their well-being and help improve their numbers.
Some of the ways we can help pollinators are:
- Grow more gardens and have fewer lawns because gardens provide a home and food source for many pollinators.
- Choose plants native to your region that will support the ecology of animal and insect pollinators in your area.
- Provide water sources that attract essential pollinators such as birds and bees into your environment.
- Avoid chemical inputs such as fertilizers, pesticides, and herbicides that could kill your pollinators or their food source.
- Mulch carefully and naturally use substrates such as grass or shredded newspaper instead of black polythene.
- Do not mow your lawn so often but let it grow as it provides a food source for pollinators when the grasses and shrubs crop up.
- Learn to love imperfections in your plants, as these indicate that the resources you have cultivated are not going to waste. These provide feed and homes for pollinators.
Pollinators occupy a very important part of the ecosystem of the world as a whole since they ensure continued plant growth. Plants support the remaining life on the planet in various forms.
Conclusion
Pollination plays a critical role in supporting the environment by ensuring the continuity of plant growth that provides essential products like food and shelter to all organisms.
Therefore, we must ensure we take care of our pollinators through the methods discussed above to safeguard the benefit we reap from them.