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Introduction
Most flowering plants reproduce sexually, i.e. through seed formation. Fertilization is essential for sexual reproduction. For fertilization and further development, the male and female gametes must meet. Ever wonder how plants maintain their continuity on the earth, despite being mobile? Let’s have a quick discussion about pollination.
Pollination of Plants
Reproduction is a process that allows an organism to reproduce its offspring. This involves many events. Pollination is an important part of that process.
Definition of Pollination
“Pollination” is the pre-fertilization process or event where pollen grains are transferred from anther to the stigma of the flower.
Plants cannot move. They cannot reproduce with one another by themselves. This is why they need a vector. The process of pollination, which combines the male and the female gametes and aids in fertilization, is called “pollinating”. You can categorize it into self-pollination or cross-pollination. This is done with the help of many vectors/agents. It must be between the same species to ensure successful pollination.
Types Of Self-pollination And Cross Pollination
Pollinations can take place within a flower, between flowers from the same plant, or between flowers from different plants. This is why pollinations can be divided into three types:
Autogamy
This is a form of self-pollination in which the pollen grains are transferred from the anther and stigma to one flower. Autogamy requires that the stigma and anther are opened, matured and exposed in a coordinated manner. Two conditions are required for autogamy:
- Anther-stigma synchronization: When the pollen is released stigma should be available to receive it
- The distance or position between the stigma and anther. Both must be close enough to pollinate
The stigma and anther are visible in chasmogamous flowers. Cross-pollination is possible in chasmogamous plants because of the exposed reproductive parts. Although cleistogamous flowers do not have anther or stigma, they are close enough to be transferable. Cross-pollination is almost impossible in cleistogamous plants. They also don’t require any pollinating agents.
Geitonogamy
Geitonogamy refers to the method of self-pollination where pollen grains are transferred from the anther into the stigma between flowers of the same plant. Although it may look like cross-pollination, and occurs with the aid of pollinators both gametes come from the same plant.
Xenogamy
Cross-pollinating is when pollen grains are transferred between two plants. This is called Xenogamy. This is the transfer of pollen from one plant’s anther to another.
Each type of pollination is unique. Xenogamy results in a new variety while autogamy preserves parental characteristics. This task is accomplished by many adaptations that plants have. Flowers also depend on specific pollinating agents, which can be either biotic or abiotic. Collectively, these biotic and abiotic pollinating substances are called pollinators.
Pollinating Agents
For pollination, plants use both biotic as well as abiotic agents.
Biotic agents are animals, insects and butterflies. Entomophily is the term for pollination by insects, while ornithophily is the term used to describe bird-insect interaction. Zoophily is the term for pollination by vertebrates.
Abiotic agents: Wind and water. Anemophily is wind pollination, while hydrophily is pollination by water.
Conclusion
In order to survive in the environment, it is necessary. The human population, as well as all of the earth’s terrestrial ecosystems, would perish if pollinators were no longer there. On average, about 80 percent of the 1,400 crop plants farmed throughout the world, which include those that provide all of our food and plant-based industrial products, require animal pollination in order to produce fruit and seeds.
