Do you ever wonder why are the flowers so brightly coloured? What attracts bees to them? Flowers aid in the reproduction of plants. The transmission of pollen grains from a flower’s male anther to its female stigma is known as pollination.
What is pollination?
Pollination is the process of pollen grains being transferred from stamens, the floral components that generate them, to the ovule-bearing organs or the ovules (seed precursors). Pollen is basically trapped in a drop of liquid generated by the ovule in plants like conifers and cycads, where the ovules are visible. The ovules of flowering plants, on the other hand, are held within an empty organ called the pistil, and pollen is discharged on the stigma, the pistil’s receptive surface. Pollen fertilization occurs there, forming a pollen tube that extends down through the pistil toward one of the ovules at its base. One of the two sperm cells within the pollen tube merges with the ovule’s egg cell, allowing for the growth of an embryo, while the other cell fuses with the ovule’s two secondary sexual nuclei, allowing for the production of a reserve food component called endosperm. The developing ovule then matures into a seed.
Pollen grains are transferred from the anther of one flower to the stigma of another flower during pollination. In flowering plants, as it is thought to be the earliest phase of sexual fertilisation. Pollen grains, which include male gamete, are found in the flower’s anthers.
Pollen is deposited on the stigma’s surface, while the ovules of blooming plants are kept in a hollow structure called the pistil. In other words we can understand this terms, pollination is the process through which plants reproduce.
Pollination is required for the development of fruit and seed crops, and it also plays a significant role in plant breeding projects. Moreover, pollination research is essential for understanding the development of blooming plants and their current distribution. Because plants are sedentary creatures, pollen delivery is largely entrusted to external agencies. In flowering plants, they include insects, wind, birds, animals, and water (in approximately decreasing order of importance).
Process of Pollination
As we can understand how the process of pollination takes place from the details given below :-
As we know fertilization process starts when pollen grains from various flowers from same species settle on the stigma and create a pollen tube the length of the style that joins the stigma and the ovary. The male gametes are contained in the pollen tube, which finally fuse with the egg cell within the embryo sac. Fertilization is the process of a male gamete and an egg fusing together to generate a zygote and, eventually, a seed. Seeds germinate and grow into new plants.
Types of Pollination
There are two types of pollination.
- Self- Pollination
- Cross-Pollination
Self-Pollination
Self-pollination occurs whenever pollen is transported from the anthers of a flower to the stigma of the same bloom. The Hermaphrodite or dioecious plants are types of plants, which have both male and female sexual components on the same flower, frequently use this method of pollination.
And there is less reliance on external stimuli to trigger pollination in self-pollinating plants. Wind or other tiny insects that visit the bloom on a frequent basis are necessary for these plants to survive. The anthers and stigma of self-pollinating flowers are of comparable lengths to aid pollen transport. Self-pollination is further subdivided into two categories:
As it is said that pollen is transmitted from the anthers of one flower to the stigma of another flower in this sort of self-pollination.
Anthers are transmitted from the anthers of one bloom to the stigma of another flower on the similar plant in this sort of self-pollination.
Cross-Pollination
Pollen is transmitted from one flower’s anthers to another flower’s stigma in this sort of pollination. The two blossoms in this scenario are genetically diverse from one another. Cross-pollination is always reliant on the presence of some other agent to transmit pollen. Pollination is carried out by birds, animals, water, wind, and insects. Cross-pollination can take several forms depending on the pollination source.
How is pollination carried out by different sources?
We can understand this by few examples given below :-
Just one emergence of the newer flower, which offers their food, allowed moths and butterflies (Lepidoptera) to evolve. Almost all Lepidoptera species have a tongue, or proboscis, that is uniquely suited for sucking. At rest, the proboscis is coiled, but when feeding, it is stretched. Hawkmoths hover over the bloom while feeding, whilst butterflies land on it. Several butterflies can taste sugar solutions with their feet, which is unusual. Despite the fact that moths and butterflies are both nocturnal and diurnal, both have been shown to have a colour sense. In general, Lepidoptera’s colour perception is comparable to that of bees, however red colours are also recognised by swallowtails and other butterflies. Throughout many cases, colour and aroma work together to attract Lepidoptera to flowers.
Agents of Pollination
Pollinating agents include insects, birds, and bats, as well as water, wind, and even the plants themselves, in the case of self-pollination within a closed bloom. Within a species, pollination is common. In nature and in plant breeding, cross-pollination between species can result in hybrid progeny.
Advantages of Pollination
Pollination is required for nearly all seed plants on the planet. This is true for both cone-bearing plants like pine trees and the more colourful and well-known floral species. Pollen, which appears to be inconsequential yellow dust, contains the male sex cells of a plant and is an important link in the reproductive cycle.
Wildflowers can benefit from appropriate pollination in the following ways:
Produce enough seeds for dissemination and multiplication by reproducing and producing enough seeds.
Ensure that a population’s genetic diversity is preserved.
Produce enough fruits to tempt seed dispersers.
Disadvantages of Pollination
Cross pollination has the following disadvantages: – A large amount of pollen grains is wasted; – There is a risk of genetic recombination, which could result in the parent’s good qualities being lost; – There is a risk of genetic recombination, which could result in the parent’s good qualities being lost.
Self-pollination is the other type of pollination. The pollen grain formed in the anther falls directly into the stigma of the same flower in this procedure. It’s most common in bisexual blooms.
Conclusion
Pollination is the process of pollen grains being transferred from stamens, the floral components that generate them, to the ovule-bearing organs or the ovules. The transmission of pollen grains from a flower’s male anther to its female stigma is known as pollination. The ovules of flowering plants, on the other hand, are held within an empty organ called the pistil, and pollen is discharged on the stigma, the pistil’s receptive surface. Pollen grains are transferred from the anther of one flower to the stigma of another flower during pollination. Pollen is deposited on the stigma’s surface, while the ovules of blooming plants are kept in a hollow structure called the pistil.