Pollination- Definition, Diagram, Process, Types

Table of Contents

Pollination Definition

Pollination: Do you ever wonder why the flowers have such vibrant colors, a great fragrance, and an elegant shape? It is used to attract insects in order to allow fertilization or pollination to be successful. Pollination is the transfer of pollen from the stamens, the male part of the flower, to the ovule-bearing organs or the ovules, the feminine component of the flower. Self-pollination and cross-pollination are the two types of pollination. Read the full article to know more details about different types of Pollination, Agents of pollination, How pollination occurs, and more.

Pollination Meaning in Biology

Pollination Meaning in Biology: Pollination is defined in angiosperms as the positioning or movement of pollen from the anther to the stigma of the exact same or another flower. When pollen is transferred, it develops to generate the pollen tube and the sperm that fertilize the egg. Pollen transfer from the male cone to the female cone occurs during pollination in gymnosperms.

Pollen collected from the anther ends up on the stigma of the same flower or another flower on the same plant, resulting in self-pollination. The movement of pollen from the anther of one flower to the stigma of a separate flower on another specimen of the same species is known as cross-pollination.

Agents of Pollination

Flowers depend on vectors to transport pollen. “Pollinators” are animals or insects that carry pollen from plant to plant. The “agents of pollination” are the agents or media that can transmit pollen grains for pollination. Wind, water, birds, insects, insects such as butterflies, bats, and various other creatures that visit flowers are examples of vectors.

Agents of Pollination Air – Air pollination occurs when light and dry pollen grains are blown by the wind to other plants.
Agents of Pollination Water – Water pollination occurs when pollen or the male part of a flower is conveyed by a water current to the female bloom to pollinate it.
Insect pollination – The vivid colors of the corolla and nectar attract insects, and pollen grains adhere to the body of the insect, allowing it to pollinate another flower as it approaches.
Animal pollination:

Pollination Process with Diagram

The plant pollination process describes the essential technique of sexual reproduction in plants. It allows a plant to produce fruit and seeds, many of which are consumed not only by humans but also by other species of life ranging from birds to animals.

The male part of the flower consists of the anther and filament referred to collectively as the stamen and the female part of the flower, consists of the stigma and style, with the ovary which includes the ovule at the bottom of the flower referred to collectively as the carpel.
A pollen particle on the stigma develops into a small tube that extends all the way down the style to the ovary. This pollen tube transports a male gamete to an ovule where it will meet a female gamete.

The two gametes connect and their chromosomes merge in a process known as fertilisation so that the fertilised cell has a normal complement of chromosomes, including a few from each parent flower.
The fertilized ovule develops into a seed, which includes food storage and an embryo that will eventually develop into a new plant.
To safeguard the seed, the ovary grows into a fruit. Avocados, for example, have only one ovule in their ovary, hence their fruit has only one seed. Many flowers, such as kiwifruit, have a large number of ovules in their ovary, hence their fruit contains a large number of seeds.

How Pollination Occurs with Diagram?

The four phases of the pollination process are depicted below in simple language.

Stage 1: A pollen grain touches down on the sticky stigma.
Stage 2: A pollen tube develops from a pollen grain and travels up the style, bringing a male gamete with it until it reaches the female gamete in an ovule.
Stage 3: Fertilization happens when the male and female gametes unite.
Stage 4: The ovule grows into a seed, and the ovary into a fruit that protects the seed.

Pollination Types

Pollen transport across an anther to a stigma is accomplished by insects, birds, bats, and the wind. A sperm cell obtained from a pollen grain created from the same flower or another flower on the same plant can fertilize an egg cell in the ovule of a flower. On this basis, the Pollination Process can be classified into two types:

Two Types of Pollination –

Cross Pollination – Cross-pollination is the passing on of pollen from one plant’s anther to the stigma of another.
Self Pollination – Pollination of a flower by its own pollen in a flower with stamens and a pistil is known as self-pollination.

Self Pollination

Self-pollination occurs when pollen from a single flower pollinates the exact same flower or different ones on the same plant. This process is easy and quick, which reduces genetic variety because the flower’s sperm and egg cells carry some genetic data. In flowering plants, there are two types of self-pollination, which are defined here.

Types of self-pollination

Autogamy – Pollen is transmitted from the anther to the stigma (female portion) of the same flower in autogamy.
Geitonogamy – Geitonogamy is the transmission of pollen from one anther to the stigma of another flower on the same plant.

Advantages –

The pureness of the race is maintained during the self-pollinating process since there is no genetic variability.
Recessive traits are eliminated through self-pollination.
When compared to cross-pollination, pollen grain waste is quite low.
External forces such as wind, water, and other pollinating agents are not involved in self-pollination.
Self-pollination promotes a high rate of pollination success.

Disadvantages –

The main disadvantage of self-pollinating is that there is no gene recombination.
The race’s vibrancy and vitality have diminished.
The immunity to illnesses in the progeny is lowered.

Cross-Pollination

Cross-pollination is a type of fertilization in which sperm from one plant’s pollen (anther) is transmitted to the stigma of another plant’s flower. It reduces the likelihood of a plant species having offspring that are susceptible to illness or have genetic drawbacks due to unfavorable recessive genes. The more diversified the genes or alleles in a gene pool, the better protected they are from extinction.
Cross-pollination produces more new genotypes than self-pollination. It contributes to increased genetic diversity. It also avoids inbreeding depression, which occurs when the biological viability of a population is diminished due to inbreeding.

Types of Cross Pollination –

Cross-pollination involves the assistance of biotic and abiotic factors like as birds, mammals, wind, insects, water, and other pollinators.

Pollination by Wind: Anemophily

Wind pollination is used by only a few flowers, and the flowers are greenish, tiny, and odorless. Because these flowers aren’t appealing to pollinators. This sort of pollination happens when plants lack nectar-producing flowers and other distinguishing characteristics such as inconspicuousness.
Wind-pollinated plants include coconut, palm, maize, grasses, and all gymnosperms.

Artificial Pollination: Anthropophily

Humans perform artificial pollination, also known as Anthropophily. In this process, methods of hybridization are also applied.If the pollination process is hampered by abiotic or biotic agents, an artificial form of pollination is used by dispersing pollen grains across the female flowers.

Pollination by Animals: Zoophily

Animals aid in the spreading of seeds. When an animal consumes the fruit of a plant, it moves to a new area. This movement aids in the dispersal of seeds, resulting in the introduction of fresh plants to new regions.

Advantages –

As a consequence of genetic recombination, recessive traits in the lineage are removed.
The seeds generated have power and vibrancy.
Cross-pollination is the process through which all unisexual plants reproduce.
Improves offspring immunity to illnesses and other environmental influences.
Cross-pollination inserts new genes into a species sequence.

Disadvantages –

There is a significant amount of pollen grain waste in this operation.
Because of DNA recombination throughout meiosis, there is a potential that excellent attributes will be lost and bad features will be added to descendants.

Autogamy Pollination

Autogamy occurs when pollen grains are transported from the anthers of a flower into the stigma of the same flower. The egg cell combines with the sperm cell created from the same flower’s anthers.

Self-pollination, a reproductive technique used by many blooming plants, is the most common kind of autogamy pollination observed.
Autogamy pollination does not result in genetic differences in the offspring.
Cleistogamous flowers are pollinated in this way. It includes sunflowers, orchids, and peas.

Geitonogamy Pollination

Geitonogamy is a sort of self-fertilization as well. It does not occur on a single flower, but rather on many flowers on the same plant. The movement of the grain of pollen from the anther to the stigma of another flower of the same plant is represented by geitonogamy.

Wind, bats, water, insects, birds, and animals are pollinators.
Cucurbita maxima, for example.
Geitonogamy and autogamy are both forms of self-pollination that are required for two times fertilization.