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Fertilization, also known as reproductive fertilization, syngamy, and pregnancy, combines gametes to produce a new living thing or offspring and start its growth. Processes such as breeding or fertilization that occur before the incorporation of gametes are also sometimes incorrectly termed fertilization. The cycle of reproduction and development of young people is called gender production. During the double fertilization of angiosperms, the haploid male gamete combines with the haploid polar nuclei to form a triploid primary endosperm nucleus through plant fertilization.
What Is Double Fertilization?
Double fertilization is a key feature of flowering plants. In these cases, one female gamete combines with two male gametes. One of the male gametes fertilizes the egg, which leads to the formation of a zygote, and the other unites with two polar nuclei to form endosperm.
Double fertilization produces plant encouragement that leads to uterine growth in the fruit and the development of ovules in the offspring. The plant’s diploid status is restored when haploid male and female gametes meet.
Double Fertilization Process
The process of fertilization is described below:
Double fertilization in Angiosperms
- Angiosperms are flowering plants and are a very different group of earthy plants. The flowers form the reproductive tract of angiosperms with different male and female organs. Each contains gametes – sperm and egg cells, respectively.
- Pollen helps pollen grains to achieve stigma in style. Two sperm cells enter the ovule-synergid cell. This leads to fertilization.
- In angiosperms, fertilization causes two genes: zygote and endosperm, hence the term “double fertilization.”
- Double fertilization is a complex process in which in two sperm cells, one joins the egg and the other joins the two resulting white nuclei of the diploid (2n) zygote and the triploid (3n) core endosperm nucleus (PEN), respectively.
- Since endosperm is the product of a combination of three haploid nuclei, it is called triple fusion. Finally, the primary endosperm nucleus grows into a primary endosperm cell (PEC) and then into an endosperm.
- The zygote becomes a fetus after several cell divisions.
Embryo development in Angiosperms
When fertilization is complete, embryonic development begins, and no more sperm can enter the uterus. The fertilized egg grows into a seed, and the uterine tissues produce a fleshy fruit that closes the sperm.
After fertilization, the zygote divides into terminal and basal cell bases. The basal cell grows into a suspensor, facilitating the transport of nutrients to the developing embryo. The killer cell grows into a pro-embryo.
The following are the various stages involved in embryonic development.
Stages of Embryonic Development in Angiosperms
- In the early stages of development, the killer cell divides into a globular pro-embryo. The basal cell also divides, becoming a suspensor.
- The developing embryo develops a heart-shaped structure due to the presence of cotyledons.
- The developing embryo is compacted and begins to bend.
- The embryo is completely absorbed in the seed.
The Importance of Double Fertilization
The importance of double fertilization is as follows:
- Two products are obtained due to double fertilization.
- There is a chance of polyembryony, and the plant has a better chance of survival.
- Double fertilization causes the endosperm to provide nourishment to the developing embryo.
- Increases the activity of angiosperms seeds.
- It uses both male gametes produced by pollen grains.
Reproductive structures in Angiosperms
Angiosperms are plant-based plant life with the result and are the most common forms of plant life in the world. Plants are the reproductive structures of angiosperms. They contain four main sections:
- Carpel: A female reproductive structure that makes eggs.
- Stamen: The male reproductive system that makes sperm cells.
- The leaves: Surround the carpel and stamen and remain brightly colored.
- Sepals: Take the flower petals before they open.
During flowering, two systems are formed: the zygote and the endosperm. The zygote will grow and develop into an embryo, or embryo, of a baby plant. The endosperm is a feeder of the embryonic plant. The process of making zygote and endosperm is called double fertilization, and it is a square mile in angiosperms.
Pollination
Pollen is needed before double fertilization. When the pollen grains produced by a flower stamp reside on the surface of another flower, this is known as pollen. The pollen grains should be especially concentrated in the sticky, or discriminatory, carpel. Pollen is a protective structure that contains sperm. The pollen tube grows when it falls on the stigma. This structure will develop from the carpel style to its ovary. Double pregnancy will occur in the uterus.
Conclusion
The process of fertilization begins with the formation of seeds in flowering plants (angiosperms) by combining two male gametes (sperm cells) and two female gametes (egg and the middle cell) to form the frontal cells of the embryo and endosperm, respectively. Under the influence of a particular pollen tube and attractive processes, immature sperm cells are transported by the pollen tube to the ovary that resides in the female gametophyte. Two sperm cells fertilize an egg, and a cell in the middle after a pollen tube bursts into a female gametophyte, causing sperm formation.
The endosperm is composed of a fertilized middle cell, while the embryo and suspensor are formed by a fertilized egg cell, the zygote. The latter part connects the embryo with the maternal tissues of the growing sporophytic sperm. To ensure the transport of active sperm cells and the production of both active zygote and endosperm, the basic methods of double fertilization are strictly controlled. The current state of information about the growth of the directed pollen and its interaction with synergid cells leading to pollen rupture, the interaction of four gametes leading to cell adhesion, and how flowering plants prevent the entry of multiple sperm cells (polyspermy) to increase reproduction.
Also read Important Topic Of Biology: Endosperm and Embryo.
FAQs
What is double fertilization?
Double fertilization refers to combining one female gametophyte with two male gametophytes.
What is the significance of double fertilization?
Double fertilization inspires the plant as the ovary grows into a fruit. As a result of the combination of male and female haploid gametes, a diploid zygote was formed. The zygote develops an embryo, which produces a new plant.
Why is double fertilization not available in gymnosperms?
Gymnosperms do not have ovaries, and male and female gametophytes are in the cones. Although, in angiosperms, gametophytes are part of the flower. Therefore, pollen in gymnosperms occurs with the help of the wind blowing pollen into the female veins. That is why they do not show double fertilization.
Question: What are the last products of double fertilization?
Answer: The last products of double fertilization are:
- Diploid Zygote
- Basic Endosperm Nucleus
