All plants need to propagate for the growth and survival of their species. Plants reproduce by pollination. Flowers help plants to propagate. A flower is the most beautiful part of the plant and the one responsible for the process of pollination. Pollination is the transfer of pollen grains produced by the flower from its anther to the stigma of the same or different flower. This process takes with the help of natural agents like birds, insects, and biological agents like the water and the wind. These are known as pollinating agents.
Pollination of the pollen grains can occur in the same flower or in two different flowers. Based upon the location of transfer of the pollen, pollination is of the follwing two types.
We will now study these two methods of pollination and what is the difference between self-pollination and cross-pollination.
What is Self-pollination?
Self-pollination happens on a single flower. It is the primary method of pollination. It involves the transfer of pollen grains from the anther to the stigma part of the same flower. The process is straightforward and quick, and easy to understand, as well.
In this process, the pollen grains from the anther or the flower's male reproductive structure get transferred to the stigma or the female reproductive structure of the same flower or of another flower on the same plant. The pollen grains are carried by the wind, water, or animals.
Plants like orchids, oats, legumes, peas, sunflowers, peanuts, peaches, potatoes, and wheat follow self-pollination. In the case of self-pollination, the same plant's genetic material is used to form gametes, and finally, the zygote. Hence, self-pollination leads to the production of plants which do not have genetic diversity.
Self-pollination occurs in flowers when both the reproductive parts, the stamen and the carpel, mature at the same time. This method does not require any pollinating agents or any nectar and pollen to attract insects or birds.
What is Cross-Pollination?
Cross-pollination is the second and more diverse form of pollination. It occurs when there is a transfer of pollen grains from the anther of one flower to the stigma of another flower. The destination flower is a different flower of the same species. This method of pollination leads to an increase in genetic diversity. It is because the genetic information from different flowers gets shared and crossed. It results in the creation of unique offsprings. In this case, the reproductive process takes place in different plants.
Cross-pollination can be carried out by wind as well as bees and other birds or animals. Insects cross-pollinate many fruit-bearing plants like apples, strawberries, raspberries, grapes, plums, and flowers like tulips and daffodils. Wind pollination can be observed in different grasses, maple trees, and dandelions.
Differentiate Between Cross-pollination and Self-pollination
Have you ever wondered how is self-pollination different from cross-pollination? Self-pollination and cross-pollination are common pollination methods, but there is a vital difference between self-pollination and cross-pollination. The diagram below shows this.
Self-pollination and Cross-Pollination Diagram
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You can see that the pollen from the anther of the flower gets deposited on to the stigma of the same flower in the first flower.
In the second flower, you can see how the pollen from anther the first flower gets deposited on its stigma.
This picture clearly shows the self-pollination and cross-pollination difference.
Now we will differentiate between self-pollination and cross-pollination with the help of the table below.
Pollination Fun Facts
Butterflies prefer flowers with flat petals where they can easily land.
Hummingbirds like long and tube-shaped flowers in red, pink, or fuchsia colours.
Q1. How is Self-pollination Useful?
Answer: In the case of self-pollination in plants, the pollen from the anther gets deposited on the stigma of the same flower or different flower of the same plant. Due to this, the plant does not need to generate a large amount of pollen or nectar. The process is quick and there are fewer chances of its failure.
The advantages of self-pollination are as follows.
Pollination is guaranteed for surety.
Less pollen quantity needs to be generated.
It preserves parent flower characteristics.
No external factors like wind or pollinating insects are required.
Requires fewer flower characteristics like large shapes, colour, or scent.
However, there are some disadvantages to self-pollination as well.
No new plant varieties can be formed.
Genetic variation remains homogeneous.
The plant vitality decreases over time due to continuous self-pollination.
Plant immunity and sustainability also decreases.
Self-pollination mostly occurs in peas, soya beans, peanuts, orchids, and sunflowers.
Q2. How is Cross-pollination Beneficial for a Plant?
Answer: In the case of cross-pollination, the pollen from one flower gets deposited on a flower of a different plant. This can lead to the production of unique plant varieties as two different plants of the same species, or different species are involved. Cross-pollination often leads to more diverse genetic variation. It leads to the development of new plant species.
Cross-pollination comes with its benefits, which are as follows.
Offsprings have genetic variety and diversity.
Species generated have a higher rate of survival and sustainability.
The quality of the new offspring is enhanced.
Offsprings inherit the best qualities from both the parent flowers.
At the same time, cross-pollination comes with its disadvantages as well and they are as follows.
Two separate parent plants are needed for this type of pollination.
Pollinating agents are required.
Less guarantee of success of pollination.
There is a need for the production of large amounts of pollen.
Flowers need to be large, showy, colourful and scented.