Pollinating Agents or Pollinators

All living organisms reproduce. Similarly, plants also reproduce through the method of pollination. Pollination is the process of the transfer of pollen grains’ from a flower’s male part, known as anther, to its female part, known as stigma. When pollen is exchanged between flowers, seeds are produced. Seeds carry the genetic information required to grow a new plant. 

Pollen travels from one flower to the other in a variety of ways. It is always transported with the help of vectors, such as the wind, water, birds, insects, and other animals that visit flowers.

What is Pollination?

Pollination occurs when pollen grains are transferred from the anther, which is the male reproductive part of the plant, to the stigma, the female reproductive part. This results in fertilisation and the production of seeds. The nucleus of a pollen particle unites with the nucleus of an ovule to generate a zygote during fertilisation inside the ovary.

What is the importance of pollination?

Pollination is very important as it promotes the creation of new compounds that may be valuable in food or medicine as it enhances the variety within plant species. The process leads to the development of fruits, seeds, and subsequent plants used in agriculture and for livestock feed. It also helps to maintain and promote diversity within and across native plant species. 

Types of pollination

There are two types of pollination:

• Self-pollination: this type of pollination occurs within the same flower and does not require pollinating agents.
• Cross-pollination: this type of pollination occurs between the same species of flowers but from different plants. This process requires an external pollinating agent.

Agents of pollination or pollinators

As pollen cannot transfer itself, pollinating agents play an important role. Some of the agents of pollination are birds or insects that carry pollen from one plant to another. These agents are also known as pollinators. The factors causing pollination can be divided into two types: abiotic or non-living agents and biotic or living agents. 

1. Abiotic or Non-living Agents: Abiotic agents are the nonliving factors that help in the transport of pollen from one plant to another, such as wind and water. This permits the plant to focus its energy on pollen instead of flowers and nectar to attract pollinators. Pollination by wind is more common in abiotic pollination. Abiotic agents are made up of two types:

• • Anemophily (Pollination by wind/air): This type of pollination mostly occurs in flowers that are not brightly colored or perfumed. Such types of plants have petals that are either little and green, or they aren’t there at all. Typically, in these plants, the male flowers are more in number than the female ones. The anthers on such plants are adaptable, allowing them to move freely in the wind. Pollen grains have a smooth wall, are light, tiny, and dry, causing them to be easily blown away by the wind.Examples;Sugarcane, Maize, Wheat, Bamboo, Pinus.

• • Hydrophily (Pollination by water): Hydrophily, or water pollination, uses water to carry pollen, sometimes in the form of complete anthers. Such a type of pollination takes place either completely underwater or on the water’s surface, helping transmit pollen grains which can move across the water to another plant.Pollination by water is quite rare in flowering plants and is limited to about 30 genera, mostly monocotyledons. As against this, you would recall that water is a regular mode of transport for the male gametes among the lower plant groups such as algae, bryophytes and pteridophytes.
  • Hypohydrophily : Plants which are pollinated inside the water e.g., Zostera, Ceratophyllum, Najas etc.
  •   Epihydrophily : Plants which are pollinated outside the water e.g., Vallisneria (Ribbon weed).

2.Biotic or living agents: The living organisms that help in the process of pollination are known as the biotic agents. Flowers whose pollination takes place by the interference of insects, birds, and other living organisms are mostly colourful, beautiful, and also have sweet smells. These properties attract insects and birds which further act as agents of pollination or pollinators. Different types of biotic pollinators are:

• • Entomophily (Pollination by insects): Bees, butterflies, beetles, and flies are the most common pollinators for this sort of pollination. This process mostly takes place in angiosperms. Such flowers have pollen grains in a small amount, and the pollen has a rough surface that makes it easy for it to attach to insect limbs when they visit flowers in search of nectar.Yucca is pollinated by Pronuba (=Tegaticula) yuccasella
  • Ornithophily (Pollination by birds): Hummingbirds and honey thrushes are little birds that feed on flower nectar. Such flowers do not have many pollen grains. In this type of pollination, the pollen grains get attached to the beaks and mouths of pollinators and get transferred to other flowers.Examples;Bombax (red silk cotton), Erythrina (Coral tree).
  • Chiropterophily (Pollination by bats): Bats are known to pollinate Kigelia Africana, Anthocephalus cadamba, Bauhinia Monandra, and many other trees.

Conclusion

Reproduction in plants occurs by the process of pollination, which results in fertilisation and the formation of zygotes. This zygote, when matured, forms the seed, and seeds develop into new plants. It is a necessary ecological function for survival. Mankind and all of earth’s terrestrial ecosystems would collapse if agents of pollination did not exist. 

Pollination occurs mostly in plants that undergo cross-pollination. Abiotic and biotic pollination are the two main types of pollination. Plants and animals produce carbon dioxide, which flowering plants need to produce breathable oxygen. Flowering plants use their roots to hold the soil in place and their foliage helps absorb rain as it falls to the ground, which aids in cleansing the water and preventing erosion.