Content Writer-SME
Cross pollination and self pollination are the two types of pollination in plants. Pollination is the mode of sexual reproduction in which the transfer of pollen grains from the anther (male organ) to the stigma (female organ) of a flower takes place. The primary difference between cross pollination and self pollination can be understood based on the location where the pollen grains are transferred.
- The process of pollination is aided by pollinating agents such as birds, insects, water or wind.
- Transfer of pollen from the anther of one flower to the stigma of another flower is called cross pollination.
- In self pollination the pollen is transferred from the anther to the stigma of the same flower.
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Difference between Cross Pollination and Self Pollination
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The location of transferred pollen grains and genetic diversity are two main differences between cross pollination and self pollination. Apart from these two, there are some other parameters that used for distinguishing the two types of pollination. Some of them are mentioned below:
| Self Pollination | Cross Pollination |
|---|---|
| Pollen grains are transferred from the anther to the stigma of the same flower. | Pollen grains from one flower's anther are transferred to the stigma of another flower. |
| This process can occur in the same flower or another blossom on the same plant. | This might happen between two flowers that are on different plants. |
| It can only be found in genetically identical flowers. | It happens when flowers dissimilar genus come together. |
| Paphiopedilum parishii and Arabidopsis thaliana are two species that self-pollinate. | Apples, daffodils, pumpkins, and grasses are among the few species that cross-pollinate. |
| In progenies, it causes a homogeneous condition. | In progenies, it causes a heterozygous condition. |
| Self-pollination reduces genetic variation while increasing genetic uniformity. | Cross-pollination increases genetic variety while decreasing genetic uniformity. |
| It causes inbreeding. | It causes outbreeding. |
| The gene pool is reduced. | Keeps the gene pool healthy. |
| Pollen grains are produced in little quantities. | Pollen grains in enormous quantities are produced. |
| Both the stigma and the anther mature at the same time during self-pollination. | Both the stigma and the anther mature at different periods in cross-pollination. |
| Only a small amount of pollen is transferred. | Pollen is transferred in vast quantities. |
| Even when the flowers are closed, this process continues. | The flower must be open for cross pollination to occur. |
| Pollinators are not required to transmit pollen grains. | Pollinators should be required to transmit pollen grains. |
| Pollen grains are delivered directly to the stigma of a flower. | Pollen grains are spread by the wind, insects, animals, and water, among other things. |
Definition of Cross Pollination Vs Self Pollination
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There are two types of pollination through which the transfer of pollen grains takes place from the anther to the stigma, namely cross-pollination and self-pollination. The type of pollination depends mainly on the type of flower and the place where the pollen falls. The first line of difference between cross-pollination and self-pollination can be understood from their definition which is explained in detail below:
What is Cross Pollination?
The more diversified type of pollination is cross pollination. It occurs when pollen grains from the anther of one flower are transferred to the stigma of another flower of a different plant but the same species. The genetic diversity in cross pollination is one of the major differences between cross pollination and self pollination.
- This is because genetic information from several flowers is shared and crossed resulting in unique progeny.
- Wind, bees, birds, and animals are all capable of cross pollination.
- Cross pollination by the wind can be seen in a variety of grasses, maple trees, and dandelions.
What is Self Pollination?
Self pollination is one of the most common types of pollination that occurs on a single flower. It is defined as the process in which pollen grains are being transferred from the anther to the stigma of the same flower or another flower of the same plant.
- Self pollination occurs when the carpel and stamen (reproductive organs) mature at the same time.
- In self pollination, the genetic material from the same plant is used to create gametes which eventually forms a zygote.
- This results in flowers with minimal genetic variation.
Types of Cross Pollination and Self Pollination
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The comparison between cross pollination and self pollination can also be done based on their types. There are several types of cross pollination through which pollination occurs in plants. The agents used for such type of pollination are called pollinating agents.
Types of Cross Pollination
The four important types of cross pollination in plants are:
- Anemophily: The type of cross pollination that occurs with the help of wind is called anemophily.
- Hydrophily: In plants like Hydrilla and Vallisneria, pollination occurs with the help of water and this type is called hydrophily.
- Ornithophily: The type of pollination that occurs by birds is called ornithophily. Hibiscus and Bigonia are the examples of bird-pollinated flowers.
- Entomophily: The bright coloured flowers such as Bougainvillea pollinate with the help of insects and this type is called entomophily.
Types of Self Pollination
Like cross pollination, self pollination is categorized into three types:
- Autogamy: in this type, the transfer of pollen grains occurs from the anther to the stigma of the same flower. Green gram, black gram, chickpea, soya, etc are examples of autogamy self-pollination.
- Geitonogamy: The transfer of pollen grains from the anther of a flower to the stigma of a different flower present on the same plant. Maize is a common example.
- Cleistogamy: It is a type of self-pollination where the transfer of pollen occurs when the flower is closed (before blooming). Examples of celistogamy flowers are Viola, Oxalis, etc.
Examples of Cross Pollination and Self Pollination
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The common examples of plants that undergoes cross pollination are fruit-bearing plants such as apples, strawberries, raspberries, grapes, and plums, as well as flowers such as tulips and daffodils, are pollinated by insects.
Examples of Self Pollination
The common examples of plants that undergoes self pollination are
- Orchids,
- Oats,
- Legumes,
- Peas,
- Sunflowers,
- Peanuts,
- Peaches,
- Potatoes, and
- Wheat.
Things to Remember
- The transfer of pollen grains occurs by pollinating agents like wind, water, insects, bees, birds, animals, etc.
- Abiotic and Biotic pollination are the two types of pollination methods.
- This process commonly occurs in angiosperms and gymnosperms.
- A common example of mutualism is pollination.
- A bisexual flower is capable of both cross and self pollination.
- Autogamy, geitonogamy, and cleistogamy are three types of self pollination.
- Anemophily, Hydrophily, Ornithophily, and Entomophily are the types of cross-pollination.
Sample Questions
Ques. What is the benefit of self-pollination? (5 marks)
Ans. Pollen from the anther is deposited on the stigma of the same flower or a different blossom of the same plant in the event of self-pollination in plants. As a result, the plant does not need to produce a lot of pollen or nectar. The procedure is fast, and the chances of it failing are slim.
The following are some of the benefits of self-pollination.
- Pollination is a foregone conclusion.
- Pollen must be produced in smaller quantities.
- It keeps the qualities of the parent flower.
- There are no external elements necessary, like wind or pollination insects.
- Fewer floral features are required, such as huge forms, colour, or perfume.
- Self-pollination, on the other hand, has a few drawbacks.
- There is no way to create new plant kinds.
- The genetic variation is still uniform.
- Due to continual self-pollination, the plant's vigour deteriorates over time.
- Plant resilience and long-term viability are also deteriorating.
- Peas, soybeans, peanuts, orchids, and sunflowers are among the plants that self-pollinate.
Ques. What are the advantages of cross pollination for a plant? (5 marks)
Ans. Cross pollination occurs when pollen from one flower is deposited on a flower from a different plant. As two separate plants of the same species, or different species, are involved, this can result in the formation of unique plant types. Cross-pollination frequently results in more genetic diversity. It results in the emergence of new plant species.
Cross-pollination has several advantages, which are listed below.
- Genetic diversity and variety are present in the offspring.
- Species that are created have a higher chance of survival and long-term viability.
- The new offspring's quality is improved.
- The greatest traits of both parent flowers are passed down to the offspring.
- Cross-pollination, on the other hand, has some drawbacks, which are as follows.
- This form of pollination necessitates the use of two distinct parent plants.
- It is necessary to use pollinating agents.
- Pollination success is less certain.
- The production of enormous amounts of pollen is required.
- Flowers should be huge, showy, colourful, and fragrant.
Ques. What are the requirements for self pollination? (1 mark)
Ans. Bisexuality. Bisexuality refers to the presence of male and female parts in the same flower. Self-pollination requires the existence of bisexual blooms. Hermaphrodite blooms are found on all self-pollinated plants.
Ques. Can you explain self-pollination and cross-pollination in your garden with examples? (1 mark)
Ans. Grass, catkins, dandelions, maple trees, and goat's beards are examples of plants that employ wind for cross-pollination. Wheat, barley, oats, rice, tomatoes, potatoes, apricots, and peaches are examples of self-pollinating plants. Many plants that can self-pollinate can also be pollinated by other plants.
Ques. What are the drawbacks of self-pollination? (1 mark)
Ans. The following are the three drawbacks of self-pollination: Due to continual self-pollination, this may result in the weakening of a variety or a species, lowering the quality of progeny... Because self-pollination does not produce new types, there are fewer opportunities for improvement in the next generation.
Ques. What are some of the drawbacks of cross-pollination? (3 marks)
Ans. Cross-pollination has several drawbacks because of the distance barrier, pollination may fail.
- Flowers must rely entirely on external pollinators for pollination.
- Pollen waste is increased.
- It has the potential to introduce certain unfavorable characters.
Ques. Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi? (2 marks)
Ans. Yes, a plant flowering in Mumbai is pollinated by pollen grains of the same species growing in New Delhi through the process of artificial pollination. During this process stamens are removed and the process is also called emasculation in order to stop self pollination.
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