Collegedunia Team Content Curator
Content Curator
Pollination is the most important part of the life stages of plants. A living being, be it plant, animal or human being reproduces and creates offspring. Plants reproduce with the help of flowers. Flowers in the plants help them produce seeds. These seeds have the genetic details about the plants to produce offspring. Given below are some of the details about pollination which will help you in understanding the topic easily.
What is Pollination?
The male part of the plant is known as an anther and the female part of the plant is known as stigma. Pollination is the process in which the pollen grains are taken away from the male part and are given to the female part of the plant i.e picking away the pollen grains from the anther and transferring them to the stigma. For making this whole process successful, the pollination must take place in similar species of the flower.
Pollination
Method of Pollination
The method of pollination starts when the pollen grains are transferred successfully to the stigma. After that pollen tube is created with the style length. This pollen tube acts as a link between the ovary and the stigma. Now the pollen grains transfer the sperm cells from the grains to the ovary.
When these sperm cells reach the egg cells and the ovary fertilization of plants happens. The fertilization will result in the formation seed which will grow into a plant and that plant will become the parent plant, this way the pollination cycle goes on.
Also Read:
Types of Pollination
Flowers are dependent upon the pollination process for reproduction. There are two kinds of pollination. These two types have been given below.
- Self Pollination
- Cross-Pollination
Self Pollination
This type of pollination occurs in a single flower and is the primary method of pollination. This happens when the pollen grains fall from the anther to the stigma directly in the same flower. This method of pollination is quick and simple. Here the egg cells and the sperm share similar genetic details which tends to the mitigation of the genetic diversity.
Self Pollination
Advantages of Self Pollination
- Self-Pollination guarantee the removal of recessive characters
- Self-pollination when compared to cross-pollination, here the wastage of pollen grain is less.
- The egg cells and the sperm share similar genetic details which tends to the mitigation of the genetic diversity.
- The external factors like rain, wind, etc are not involved in self-pollination.
- Ensures a good rate of success in pollination
Disadvantages of Self Pollination
- Genetic diversity is missing in Self-Pollination.
- Offsprings have reduced immunity in this kind of pollination.
Cross Pollination
Unlike Self-Pollination, Cross-Pollination as the name suggests happens from one flower to the other. Here, the pollen grains are transferred from the anther of the flower to the stigma present in the other flower. By Cross-Pollination, the genetic diversity increases. The flowers share their genetic details, as a result, a unique offspring is created.
Cross Pollination
Types of Cross Pollination
Cross-Pollination happens with the help of wind, water, air, birds, animals, butterflies, etc. The types of cross-pollinations have been discussed below.
- Anemophily: Pollination by wind is known as anemophily. The small, odorless, and greenish flowers use anemophily for cross-pollination. Here plants do not attract other pollinators because these kinds of plants do not produce attractive flowers with nectars and hence wind is the only pollinator to spread the pollen grains. Flowers doing pollination by wind have light and free-swinging anthers, this helps in the pollination by air easily. Examples of plants doing pollinating by wind are palm, coconut, maize, etc.
Anemophily
- Zoophily: zoophily means pollination with the help of animals. Here, animals play an important role in the dispersal of seeds. Animals move to different areas after eating the fruit of the plant. By moving they spread the seeds. Zoophily is divided into three categories:
- Ornithophily: Pollination with the help of birds
- Entomophily: Pollination with the help of insects
- Chiropterophily: Pollination with the help of bats
Hydrophily
Pollination with the help of water is known as hydrophily. The pollen grains are transferred by the flow of streams and rivers. Two methods are there in which pollination takes place in water.
- Surface Pollination: As the name suggests, here the pollen grains float on the surface of the water and get transferred to the stigma.
- Submerged Pollination: It is where the pollen grains sink inside the water and get transferred to the stigma.
Hydrophily
Advantages of Cross-Pollination
The advantages of Cross-Pollination are given below:
- The seeds produced by cross-pollination are of good quality.
- Cross-Pollination is the method of reproduction for unisexual plants.
- Cross-pollination helps to remove the recessive characters by genetic recombination.
- Immunity of the plants reproduced by cross-pollination increases.
- Gene variety is there due to the fertilization of genetically varied gametes.
Disadvantages of Cross-Pollination
The disadvantages of Cross-Pollination are given below:
- There is a lot of wastage of the pollen grains
- Sometimes, unwanted characteristics are also adapted by the plants reproduced by this method, and good characteristics get eliminated.
Things to Remember
- The male part of the plant is known as an anther and the female part of the plant is known as stigma.
- The method of pollination starts when the pollen grains are transferred successfully to the stigma.
- Self Pollination occurs when the pollen grains fall from the anther to the stigma directly in the same flower.
- Cross-Pollination occurs when the pollen grains are transferred from the anther of the flower to the stigma present in the other flower.
- Pollination by wind is known as anemophily.
- Zoophily means pollination with the help of animals.
- Pollination with the help of water is known as hydrophily.
Also read:
Sample Questions
Ques. What is Hydrophily? (2 Marks)
Ans. Hydrophily is also known as water pollination and is most commonly shown as pteridophytes, bryophytes, or algae. Many plants found in water such as hyacinth or lily come above the water level and in these plants, the pollen grains are dispersed by the wind or insects. In the water-pollinated species, the pollen grains are prevented by the mucilaginous covering.
Hydrophily Diagram
Ques. In plants, what are the stages after fertilization? (2 Marks)
Ans. The stages after fertilization in plants are given below:
- Endosperm development
- Embryo Improvement
- Development of ovary into a fruit
- Development of ovule into a seed.
Ques. Mention the female and the male reproductive parts of a plant. (2 Marks)
Ans. The female and the male reproductive parts of a plant are mentioned below:
Male reproductive parts: the stamen, the anther, and the filament. They are collectively called the androecium.
Female reproductive parts: stigma, styles, ovary, pistils, carpels. They are collectively called gynoecium.
Ques. Mention the important layers of a flower. (2 Marks)
Ans. The important layers of a flower are given below:
- Calyx
- Corolla
- Androecium
- Gynoecium
Ques. What happens after the fertilization process in plants? (2 Marks)
Ans. After the fertilization process in plants the following things happen:
- The ovary is converted into fruits.
- The ovule is converted into seeds
- Calyx, corolla, androecium, and gynoecium degenerates
Ques. What is the significance of Pollination? (2 Marks)
Ans. The significance of Pollination is given below:
- Pollination is an important step for the fertilization of plants.
- Pollination helps in carrying the pollen grains that are transferred successfully to the stigma.
- Pollination helps in creating hybrid seeds
- Pollination helps in recombinations
Ques. What are the 4 stages of Pollination? (3 Marks)
Ans. The 4 stages of Pollination are mentioned below:
- The first stage is Pollination where the pollen grains are transferred successfully to the stigma.
- The second stage is germination, where pollen tubes develop and help the sperm in reaching the egg.
- Ovules containing the female gametes are penetrated by the pollen tubes.
- Sperm fertilizes the egg by reaching it with the help of pollen tubes.
Ques. Explain double fertilization. (3 Marks)
Ans. Double fertilization happens in stages. All the stages have been mentioned below.
- In angiosperms, two male gametes travel the pollen tube to reach the egg.
- One of the male gametes produces a zygote by fusing with the egg. The process of fusing is called syngamy.
- The second male gamete fuses with the secondary nucleus and creates a primary endosperm nucleus. This is known as triple fusion.
- Two fusions are happening in this process and so this process is known as double fertilization.
Ques. What is the difference between wind-pollinated and insect-pollinated flowers? (3 Marks)
Ans. The difference between wind-pollinated and insect-pollinated flowers is given below:
| Wind-Pollinated Flower | Insect-Pollinated Flower |
|---|---|
| Small in size | Large in size or form clusters |
| These flowers are dull-colored | These flowers are bright-colored |
| They don’t have nectars and smell | They have a strong smell and nectar is present |
| Pollens are present in large numbers | Pollen grains are small in number |
| Examples: Parthenium, Urtica, Maize | Examples: Calotropis, Rose, Snapdragon |
Comments