Self Pollination and Cross Pollination

The process of pollination is a transportation process of the male reproductive part of the pollen from the anther to the stigma of the flower. The male reproductive part of the flower consists of the filament and anther and is known as the stamen while the female reproductive part is known as the carpel or pistil which further is made of three parts the stigma, style and the ovary. The process involves the dropping of the pollen to the sticky stigma surface and further it moves down through the style and finally in the ovary it fuses with the female reproductive structure the ovule leading to fertilisation.

The process of pollination is not easy as the pollen landing on the stigma is a matter of chance. For the transfer of pollen grain there are some agents like the water, wind, animals and so on. These are known as agents of Pollination.

Types of Pollination

Based on the mechanism of transfer of the pollen grain to the stigma it is called by different names these are 

• Cross pollination 
• Self-pollination

 Cross pollination

It is also known as allogamy. As the word Cross suggests in this type of Pollination the transfer of pollen grain takes place in a different plant not the same plant hence the word Cross is used, but the plant belongs to the same species. Simply put it is the transfer of pollen grain from anther to the stigma of a different plant but belonging to the same group / species. Plants that cannot perform the process of self-fertilisation are known as self-sterile.

Reasons of cross pollination 

• The plant’s female and male reproductive parts may be arranged in such a way that self-pollination or within the plant or flower pollination is not able to take place
• Variability in maturity means that the male and female reproductive parts get mature at a different time due to which self-Pollination is not possible

Advantage of Cross Pollination

One of the major advantages is the variety in genes that cross pollination brings due to the fact that the flower belongs to different plants and sometimes of a different species as well. It is also found that germination is proper and hence massive seed production and better output.

Disadvantages of Cross pollination

The main disadvantage is the requirement of a pollinating agent and hence it is not certain if the pollination will happen or not and due to this fact, the pollen also have to produce in more quantity and also to attract the plants the flowers should be coloured and full of nectar.

Self-pollination

The word self means by itself so in this process of Pollination the transfer of pollen grain takes place within the same flower or the flower of the same plant. The process is a primitive one since it doesn’t depend on the pollinating agents for transfer.

Further the self-Pollination is divided into the following subcategories. These are as follows -:

• Autogamy- when the process of Pollination takes place in the same flower
• Geitonogamy- when the process of Pollination takes place in a different flower but of the same plant

These plants are also known as self-fertile as they don’t depend on other agents for the fertilisation process.

Advantages 

The major advantage is that no pollinating agent is required and the process is more certain. Also, flowers that are pungent or not so attractive can also pollinate.

Disadvantages

No variation in variety of the flower as it belongs to the same plant and due to lack of variation, less favourable genes are also not eliminated.In the end the plant becomes weak as the undesirable character is not eliminated .

Major areas of difference between Self Pollination and Cross Pollination

• Self-pollination takes place within the same plant while cross pollination does not take place in the same plant
• Self-pollination doesn’t bring variability in genes while cross pollination does not
• Self-pollination doesn’t require pollinating agents for the transfer of pollen grain but cross pollination on the other hand cannot happen without these agents 
• In self-pollination the pollen grains are not wasted and a large be production is not required as the transfer is not agent dependent moreover it also has to happen in the same plant while in the case of cross pollination due Transfer to different plant the production of pollen is large and then also it is not certain that fertilisation will take place
• Self-pollination happens in a single plant while cross pollination happens in two plants
• Self-pollination doesn’t require the plant to be nectar rich or attractive and perfumed while for cross pollination to attract the bees and other animals the plants should be nectar rich, colourful and perfumed

Examples of plants 

In plants such as pea and orchid self-pollination takes place while in grasses and grapes cross pollination is witnessed.

Conclusion

Pollination is an import process because the end result of it is food on which human society depends. We owe a lot to the pollinators because around 80% of the food-based plants that are basically crops require these agents for pollination. Hence the process and the agents have a significant role.