Sporophyte:
The spore-producing phase of a plant’s life cycle is known as sporophyte. Plants reproduce in two stages: sexual and asexual reproduction. The alternation of generation separates these two phases into the sporophyte and gametophyte through the processes of meiosis and fertilisation.
To better comprehend the plant’s life cycle, sporophyte refers to the stage in which plants create diploid (2n) spores, which evolve into gametophytes. Haploid (n) gametes, or reproductive cells like sperm and eggs, develop during the gametophyte stage. Sperm fertilises the eggs, which develop into sporophytes.
Sporophyte’s Purpose
Plants are incredible natural marvels. They have both sperm and eggs, but they can also replicate themselves in miniature via spores. The spores are diploid cells that store genetic information about the plant, allowing it to reproduce asexually. Plants, on the other hand, can reproduce sexually through the union of a sperm and an egg.
The sporophyte’s primary role is to produce spores, as we already know. Through the process of meiosis, the spores generate gametophytes, which give rise to male and female gametes. Meiosis is a cell division process in which the number of chromosomes is cut in half. The reproductive cells are now ready to be fertilised in order to generate the sporophyte, completing the cycle.
Plants’ life cycles will be interrupted without the sporophyte, and they will be unable to reproduce. Fruits will not develop without it, and plants will have to rely on asexual ways of propagation. The genetic pool of plant species is weakened as a result of this.
Consider the following examples: Plants that produce spores are known as sporophytes. It is vital to remember, however, that all plants produce spores. Plants with sporophytes are divided into two groups: non-vascular and vascular plants, which are further divided into botanical phyla.
Non -Vascular
This refers to plants that lack a vascular system, such as xylem and phloem, which are analogous to the human circulatory system. Instead, they have simpler tissues that aid in the efficient transfer of water inside the body.
Non-vascular sporophytes include the following:
Bryophytes:
Mosses, liverworts, and hornworts are all members of the bryophyte family. These plants are largely haploid gametophytes with a diploid part consisting of the sporangium and stalk attached to the plant. They do not grow tall because, unlike vascular plants, they lack water-conducting tissues.
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Algae:
The alternation of genes from gametophyte to sporophyte generation is observed in green, red, and brown algae. Sporophytes and gametophytes appear to be the same in certain algae, although they appear to be different in some green and brown algae.
Vascular Plants with No Seeds
Vascular bundles are present in seedless vascular plants, however they do not generate seeds. The diploid sporophyte and haploid gametophyte phases of their life cycle alternate. Water is also required for sperm motility during the gametophyte stage’s gamete formation. They are usually found in damp environments.
1.Horsetail
Horsetail, also known as Equisetum, is the sole living species of the Equisetaceae genus. As a result, it is classified as a living fossil. Sporangiogenesis is the process through which spores are formed in the strobili. The gametophyte generation is microscopic, but the sporophyte generation is visible to the naked eye.
2.Ferns
Ferns are a type of plant that reproduces by spores. There are more than 10,000 extant species in this category. They have vascular bundles, leaves, and stems, unlike mosses. Fern sporophytes are often larger than free-living gametophytes.
Gametophytes:
All plants and some algal species have a life cycle called alternation of generations. A sporophyte, a multicellular diploid generation, and a gametophyte, a multicellular haploid generation, are involved in this process. Diploid indicates your cells have two sets of chromosomes and is commonly denoted as ‘2n’. The letter ‘n’ stands for haploid, which indicates your cells have only one set of chromosomes.
Purpose of Gametophytes
A gametophyte’s primary function is to produce gametes. Gametes, or haploid reproductive cells like eggs and sperm, are haploid reproductive cells. Mitosis, or cellular division without chromosomal reduction, produces them in sex organs on the haploid gametophyte. In gametophytes, there are two sex organs, or gametangia:
Archegonium (plural: archegonium): A multicellular female sex organ that produces eggs.
Antheridium (plural: antheridia) is a multicellular male sperm-producing organ.
Because both organs generate haploid egg cells, an archegonium can be compared to a human female’s ovaries. Because both generate haploid sperm cells, an antheridium is similar to a testis in human males. Archegonia and antheridia, on the other hand, are usually minute structures.
Archegonia and antheridia are found in some gametophytes. Because they have both female and male structures, they are known as bisexual gametophytes. A unisexual gametophyte is one that possesses just one type of gametangium (either an archegonium or an antheridium, but not both).
Sexual reproduction happens when a sperm cell fertilises an egg cell, and gametophytes are required for this to happen. A diploid unicellular zygote is produced during sexual reproduction and will undergo mitosis to become multicellular. The sporophyte is a multicellular diploid creature.
Formation of Gametophytes
When spores are produced by the sporophyte generation, a gametophyte is formed. Meiosis, or cell division, produces spores by halving the number of chromosomes. Because sporophytes are diploid, a diploid cell that goes through meiosis produces haploid cells. Sporophytes produce spores, which are haploid cells. After that, the spores will go through mitosis and develop into a multicellular haploid gametophyte.
Examples:
Hornwort: The hornwort gametophyte is a thin, long stalk from which the spores are expelled, and it is green, long-lived, and low to the ground.Hornwort gametophytes and sporophytes are separate organisms with distinct numbers of chromosomes.
Mosses: The gametophyte stage of moss has a long life span, but sporophytes are long stalks that release spores into the air. The gametophyte sex cells are mixed together to generate sporophytes. As a result, compared to gametophytes, they have twice as many chromosomes.
Which of the two, the gametophyte or the sporophyte that emerges first?
In different groups of plants, sexual reproduction occurs in slightly different ways. The gametophyte stage and the sporophyte stage are two separate stages in the life cycle of plants. Male and female gametes are produced by mitosis in separate multicellular structures by the haploid gametophyte. The diploid zygote, which develops into the sporophyte, is formed by the fusion of male and female gametes. The diploid sporophyte generates spores through meiosis after reaching maturity, which then divide by mitosis to produce the haploid gametophyte. The cycle resumes when a fresh gametophyte develops gametes.
Conclusion :
In the life cycle of plants and algae, the gametophyte is the sexual phase. It grows sex organs that create gametes, which are haploid sex cells that fertilise to form a diploid zygote with two sets of chromosomes. The sporophyte’s primary role is to produce spores, as we already know. Through the process of meiosis, the spores generate gametophytes, which give rise to male and female gametes. Meiosis is a cell division process in which the number of chromosomes is cut in half.