An Introduction to Fertilisation in Plants
Fertilisation in plants is the process of fusion of male and female gametes to form a zygote. There are various steps that are involved in this procedure of fertilisation. After the process of fertilisation in a flower, the development of the zygote into a flower and further fruit takes place. The process is similar in both angiosperms, which are the flowering plants, and gymnosperms, which are the fruit-bearing plants.
Fertilisation Meaning
Plant fertilisation is the process of fusion of male and female reproductive cells or gametes to produce a fertilised egg, which is a zygote. This zygote develops further and results in a flower and later fruit in the case of gymnosperms. Plants are primary producers, and plant reproduction is an important process as it helps in the production of various things like food, clothes, oxygen, etc.
Steps of Fertilisation in Plants
There are certain steps in which plant fertilisation takes place. The structure of fertilisation is discussed below in detail.
1. Pollination
Pollination is a process in which a pollen (male gamete) is transferred to the female gamete through some carriers, resulting in its fertilisation. These carriers can be the wind, water, or insects and animals. These pollens are generally present on the stigma (exposed structure) of the plant. The stigma is a part of the pistil (the elongated part of a flower extending from the ovary) of the flower. These pollens can be easily carried to the female gametes for fertilisation.
2. Germination
Once the pollen lands on the pistil, it starts germinating. This means that the pollen tubes begin growing out of them towards the egg cell for fertilisation. Through this tube, the male gamete will travel to the female gamete for the process of fertilisation.
Flower Fertilisation Diagram
3. Fertilisation
These pollen tubes, grown through the pollen, penetrate the ovule which contains the egg or the female gamete. The pollen tube enters the ovule through the area called the micropyle and bursts into the embryo sac. The sperm travels to the egg and fuses with it, resulting in fertilisation.
The fertilisation results in zygote formation in plants, which later develops into a fruit.
Following fertilisation, the zygote's cells start to divide, and it eventually turns into an embryo or growing plant. The embryo is kept latent in a seed capsule until the right environmental factors allow it to grow into a new plant.
Fertilisation in Plants Diagram
Types of Fertilisation in Plants
There are three types of fertilisation processes that are mainly classified on the basis of how the pollen tube enters the ovule. These are described below as:
1. Porogamy
This is the most common type of fertilisation. It is carried out in all angiosperms that are flowering plants. In this, the pollen tube formed through the stigma enters the embryo sac or the ovule through the micropyle.
2. Chalazogamy
Chalazogamy is a specific type of fertilisation process that takes place in the Casuarina species of plants. This type of fertilisation is particular to these species. In this type of fertilisation, the pollen tube enters the ovule through the pollen tube only.
3. Mesogamy
Mesogamy can be seen in all Cucurbit plants, such as ridge gourds, bitter gourds, pumpkins and other gourd plants. This type of fertilisation is specific to the Cucurbit plants. The pollen tube here enters the ovule through its middle part, which is called the integuments of the ovule.
Conclusion
Fertilisation in plants is a process that involves the fusion of male gametes (pollen) and female gametes (egg). The process of fertilisation in plants is facilitated by pollination, germination, etc. Ultimately, when the fusion happens, it results in a diploid zygote that further develops in fruits. There are three types of fertilisation processes based on the entrance site of the pollen tube into the ovule. The topic is an essential part of the chapter ‘Reproduction in Organisms’ for Class 10 students.
FAQs on Fertilisation in Plants
1. How do other groups of plants, like bryophytes and pteridophytes reproduce?
Bryophytes and pteridophytes are also groups of plants that are a part of the Plant Kingdom. These plants are lower in terms of development and structure in comparison to angiosperms and gymnosperms. These reproduce through sexual as well as vegetative means of reproduction. Vegetative reproduction does not involve male and female gametes, and in this type of reproduction, the new offspring comes from the existing parent plant. Bryophytes use the process of fragmentation, gemmae cups, etc.
Pteridophytes are vascular plants that reproduce asexually and sexually. They use spore formation in the case of asexual reproduction and zygote formation in the case of sexual reproduction.
2. How important is the chapter Reproduction in Organisms from the Class 10 Board’s point of view?
The chapter ‘Reproduction in Organisms’ is very important when it comes to examinations. Questions from this chapter are asked frequently. There are also long answer-type questions from this chapter as it contains a lot of concepts and processes that can be explained in detail. The chapter should be understood thoroughly and the various processes and concepts should be remembered in points to score well. The chapter also forms the basis for further studies in biology. If you plan on taking Biology for your higher grade, then this chapter has to be learnt properly.
3. What are the important topics from this chapter?
The chapter is called Reproduction in Organisms and, hence, it involves the reproduction of all types of organisms, starting from single-celled organisms to humans. It covers the topics of different types of reproduction methods in unicellular organisms as well as multicellular organisms, which will include binary fission, spore formation, etc. Then, in plants, you will study vegetative, asexual, as well as sexual types of reproduction. In this, you will also study flower parts and the process of fertilisation. Furthermore, you will study the human reproductive system.
