Pollination is an important process of fruit and seed production in plants. Some plants, they depend on pollinating agents to activate pollination. But other plants are referred to as self-pollinators.
What is the meaning of self pollination?
Self-pollination is the exchange of pollen between flowers of the same plant. It is a very common type of pollination for vegetables. The process involves pollen movement from the same plant from the anthers to the stigma.
Two main types of self-pollination can help us understand how it works. Autogamy is the case where pollen transfer is from the same flower’s stigma.
There is also geitonogamy, where the pollen from another anther of a different plant is transferred to the flower. However, both do not engage the help of pollinating agents such as insects.
What are self-pollinating plants called?
Self-pollination is also referred to as autogamy in scientific terms. The process involves the transfer of pollen between the anther and the same plant’s stigma. This can be a transfer within the same or a different flower in that plant.
Self-pollinating plants have a coordinated opening of the flowers. They coordinate the exposure of the pollen from the anther to the stigma. Several processes have to take place for self-pollination to occur.
Self-pollinating plants expose both the stigma and the anther at the same intervals and periods. This allows for easier pollination.
Anther-stigma synchronization may sound like a technical term. But it simply means the readiness of the stigma to receive the pollen.
For this to happen, the anther and the stigma must be close. These plants have well-placed anthers that can easily drop the pollen to the stigma.
How can you tell if a plant is self-pollinated?
It is simple to identify a self-pollinated plant. Experts note that self-pollinated plants do not have features to attract pollinating agents.
These plants do not have pollinator attractants such as nectar or flower color. They also grow in places where pollinating agents can hardly access them.
Distinguishing the self-pollinating plants from the others can rely on several facts. These are the facts that specifically describe self-pollinating plants.
Fact #1 They are bisexual
The self-pollinating plants are bisexual. This means that they have both male and female parts. The presence of both parts in the flower is evident when the flowers are open.
The chances of self-pollination increase as the follower remain open for longer. The male part easily drops the pollen on the female part.
Fact #2 Have small flowers
The size of their flowers also notices self-pollinating plants. They have smaller flowers. This limits the chances of the flowers attracting any pollinators.
Sometimes, these flowers do not produce scents or nectar that attract insects. The small size also allows for proximity between the anthers and the stigma for easier pollination.
Fact #3 Close stigma and anthers
The closeness of the anther and the stigma has been observed as the main strength of self-pollinating plants. This is considered the determinant of the pollen exchange. They both lie close to each other.
Any movement of the flower causes a release of the pollen. It then pollinates the plant successfully. There is also a noted feature that the stigma and the anthers mature simultaneously. This is to allow for successful pollination.
Five plants that self-pollinate
Plants that self-pollinate are easy to identify. These are very common plants in our gardens. The following are some key examples of plants that are self-pollinating.
Beans:
Beans are categorized as legumes that are self-pollinating. Beans do not need ant-pollinating agents for pollination to occur. They have the needed parts to reproduce. The beans open up their flowers and transfer the pollen with ease.
Tomatoes:
Tomatoes are in the class of vegetables that are self-pollinating. The tomatoes are known to have complete flowers with the stamen and the pistil. The plant has yellow anthers at the center of the flower that produces pollen.
Peas:
Peas are also in the category of vegetables that self-pollinate. They are also identified as perfect flowers that have both reproductive organs. However, peas are different from tomatoes. They may require some emasculation in some cases.
Carrots:
Carrots are also in the category of self-pollinating vegetables. They do not depend on the pollinating agents to exchange the pollen from the anthers to the stigma.
Cauliflower:
Cauliflower is in the category of cruciferous vegetables. These can also be reproduced without having to cross-pollinate. The cauliflower
All these plants, they adapt for self-pollination through homogamy. Homogamy is a process by which the reproductive parts mature simultaneously. At the same time, maturing ensures the timely exchange of pollen between the male and female parts.
How do you ensure self-pollination?
There is a way that a gardener can choose to promote self-pollination. This is especially when the gardener wants something other than an exchange of plant varieties. Several methods are used to ensure self-pollination.
Method 1: Mass selection
Mass selection is the selection of individual varieties of seeds. Farmers use mass selection to identify a specific breed of plants.
The farmers then isolate these plants from other varieties to avoid cross-pollination. This is very common for plants that some communities have passed across the generations.
Method 2: Pure-line selection
Pure-line selection involves the selection of a superior breed of crops in a garden. The superior-appearing plants are then preserved to replace other varieties. The process involves maintaining a specific variety for a long period.
Method 3: Hybridization
Hybridization is the process of selecting plants that will dominate the other breeds. This includes a combination of specific plant genes.
The process then limits the breed to pollinate between them. This is a method mostly used to produce pure-breeding crops.
Advantage of self-pollination
There are several pros of self-pollinating plants in a garden.
- Less wastage of pollen
One of the major advantages is that the process reduces wastage of pollen. The pollen is distributed within the same flower. There is no transmission of pollen outside the flower. Therefore, it does not drop or get wasted.
- Do not depend on external carriers
There is a major link between the poor production of crops and the inefficiency of pollinating agents. Self-pollinating works best because the insects are not involved. There are cases where insects may not be available.
Some insects may need to carry the pollen more efficiently. There is, therefore, a limitation in the exchange of pollen. Self pollination works best because the pollen is exchanged internally.
What is the disadvantage of self-pollination?
It is also good to note that self-pollination has some disadvantages for the plant.
- Seed variety limitation
One of the major disadvantages is the need for seed variety. When plants self-pollinate, they do not exchange pollen. This means that the plant depends only on its pollen. Therefore, the plant does not access any other variety of pollen.
- Decreasing seed immunity
Self-pollination also decreases the immunity of the seeds. The immunity of a plant is strengthened when plants exchange pollen.
The self-pollinated plants have the same genetic characteristics. They are therefore affected by the same diseases and pests.
Self pollination also limits the ability of a plant to adapt to different environments. This means that it is also exposed to many common pests and diseases.
The plant may also not be able to survive when the environment changes. The overall outcome is reduced health and poor species of plants.
- Negative effects of self-incompatibility (SI)
There is also another genetic barrier linked to self-pollination. This includes the is self-incompatibility. Some plants may discriminate pollen.
This means that the self-pollination process is limited. It can also lead to complete failure of the pollination process.
Why is self-pollination avoided?
It is good to note that self pollination is mostly avoided. This is because of the many disadvantages it presents to a farmer.
Self-pollination is linked to poor-quality produce. The plant does not produce a variety. It is, therefore, only recommended for some plants.