Pollination and fertilization in plants are often used interchangeably. There is a lot of confusion about whether both terms are different and if they are, what the difference is.
Here we are going to explain “how is the process of pollination different from fertilization”.
When going through our high school’s science topic “Reproduction”, we mainly concentrated on ‘Reproduction in animals’, whereas ‘Reproduction in plants’ was just read through because “it will be on the test.”
Unlike Reproduction in Animals, we never tried to explore beyond what is written in the book as we were unable to either relate on the topic or understand its significance.
Due of that many scientific terms are often used interchangeably by us even though their meaning differs. Pollination in Plants and Fertilization in plants also falls under such category. Though both pollination and fertilization in plants is closely related, their innate meaning is different.
We are going to look at those differences and gain deeper understanding of both the terms in this article-
What is Pollination?
Pollination is an act where the pollen produced by the male part of a flower, called anther is transferred with the help of animals or natural means (wind, water) to the female part of the flower, called stigma.
Types of pollination
There are two types of pollination-
- Self-Pollination- When the pollen of a flower falls to the stigma of the same flower, it is called self-pollination. This type does not make use of any external factors in the transfer of pollen grains.
- Cross-pollination- When the pollen of a flower falls to the stigma of another flower with the help of external factors, it is called cross-pollination.
Process of pollination
- The process of pollination includes fertilization of the nucleus so that it can develop into a seed. For a successful pollination in a flower, the pollen must land safely on the stigma (same species).
- After landing on the Stigma, the pollen goes through the pollen tube, that was developed through germination to reach the ovary where the ovum (egg) of the flower is present.
- After the pollen successfully reaches the ovule, the ovum and pollen merge together to form a zygote that later becomes a seed.
Who Are the Pollinators?
Animals and insects who helps in the process of pollination by carrying the pollen grains on their body and transfer them to the stigma are called Pollinators.
The most well-known pollinators include insects like Bees, Butterflies, ants etc. as well as birds like hummingbirds, honeyeaters and honeycreepers.
Apart from living pollinators there are also other pollination agents which help in the process of pollination. Thus, pollination can be divided into-
Pollination types by Agents
- Biotic Pollination- When pollination of the plants is completed with the help of living agents like birds, insects, animals etc. it is called biotic pollination.
- Abiotic Pollination- when the pollination of a plant is completed with the help of non-living agents like wind, water, or rain, it is known as Abiotic Pollination.
How do plants attract pollinators?
Plants use various techniques to attract pollinators. Few of those are-
- Fragrance or the Nectar of the flower- Many flowers attract their pollinator by their sweet-smelling fragrance or delicious nectar. For example, The Titum arum attract flies due it its smell of rotting meat.
- Shape of the Flower- The shape of the flower is an important factor in attracting pollinators as certain insects are attracted to certain flowers due to their shape which makes it easier for them to gather pollens. For example, Bluebell is a bell shaped flower that attracts bumblebees because they have a long tongue.
- Colour & Pattern- flowers also attract various pollinators with their bright colours or distinct patterns. For example, Bee orchid looks like a bee which attracts more bees to visit it.
After having an understanding of the term pollination, let’s move on to Fertilization so as to understand what differences they have between them.
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What is Fertilization?
Pollination falls under the category of physical process whereas Fertilization is a physiochemical process that happens after the pollination and germination of plants. When the male and female gamete of the flower (Pollen & Ovum) fuses together to form a zygote, it is called Fertilization.
Types of Fertilization
The types of fertilization in plants are differentiated on the basis of how the pollen tube enters the ovule. Scientifically, it can be divided into three types-
- Porogamy- When the pollen tube formed during germination enters the embryo sac through micropyle (small opening at the surface of ovule). It is seen in flowering plants.
- Mesogamy– When the pollen tube enters the embryo sac through the middle part of the sac, called integuments. It is found in cucurbit plants like pumpkins and bitter gourd.
- Chalazogamy– specific to casuarina species, the pollen tube enters the embryo sac through the chalaza, the basal part of ovule in plants.
The process of fertilization is interconnected with pollination.
- When the pollen tube is formed in style down to the ovary in germination, the pollen travels through the tube and reaches the embryo sac.
- Afterwards, the male nucleus merges with the female egg to form a zygote.
- This zygote grows to form a seed, inside which the embryo resides.
Difference between the process of Pollination and Process of Fertilization
|1) It is a physical process without any molecular change in the plant, pollen or stigma.
|1) It is a physiochemical process where the pollen goes through a molecular change to form zygote with the ovum.
|2) External agents like birds, insects, wind etc. are required in order to transfer pollen to stigma.
|2) No external agents are required in the process.
|3) This happens before Germination takes place
|3) Fertilization can take place only after germination.
|4) The pollination process is successful when the male gamete (pollen) reaches the female gamete (stigma) of the same species.
|4) The Fertilization process is successful when the ovum and pollen successfully merge to form a zygote and later a seed.
Both pollination and fertilization are part of the process of reproduction in plants but it is clear that they are not interchangeable terms. Both have their own process which are inter-related and inter-dependent.
One of the biggest differences that we noticed between them is if a physical process that does not require any chemical change whereas other is a pure physiochemical process which forms the seed of the plant.
Through this article, we hope that you gained a better understanding of process of pollination different from fertilization.
Frequently Asked Questions
Who discovered Pollination in Plants first?
Christian Konrad Sprenge was the first person to define pollination as an interaction between flower and pollen.
What do you mean by Germination?
Germination happens after pollination and before fertilization of the pollen, where pollen rehydrates itself and form a pollen tube in the style.
Why is pollination important before Fertilization?
Pollen contains male gametes necessary for reproduction. Through pollination, genetic diversity is also maintained.
What is pollination by wind called?
Pollination by Wind is called Anemophily.