Main Difference – Gametophyte vs Sporophyte
Gametophyte and sporophyte are the sexual and asexual phases that occur during the alteration of generations of plants. Both gametophyte and sporophyte are multicellular structures. The gametophyte produces male and female gametes directly from its plant body. In contrast, sporophyte produces haploid spores by meiosis. Algae and bryophytes contain a dominant gametophytic stage. The sporophyte is dominant on pteridophytes, gymnosperms, and angiosperms. The gametophyte represents the sexual phase and sporophyte represents the asexual phase of the plant life cycle. The main difference between gametophyte and sporophyte is that gametophyte is a haploid and is produced by meiosis whereas sporophyte is a diploid and produced by mitosis.
This article looks at,
1. What is Gametophyte
– Definition, Formation, Characteristics
2. What is Sporophyte
– Definition, Formation, Characteristics
3. What is the difference between Gametophyte and Sporophyte
What is a Gametophyte
A gametophyte is the multicellular, haploid generation that is produced during the alteration of generations of plants and algae. It begins with a haploid spore and produces gametes in gametangia by mitosis. The fertilization of gametes produces the diploid zygote that is developed into the sporophyte. The gametophyte is visibly dominant in bryophytes and algae. Some bryophytes like liverworts develop male and female gametophytes separately by the germination of microspores and megaspores respectively. In ferns, the gametophyte is independent of its sporophyte though it is not the prominent form of the plant body in ferns. In seed plants, the gametophyte is reduced into the microscopic level. The male and female gametophytes of Marchantia, which is a liverwort are shown in figure 1.
Figure 1: Marchantia male (left) and female (right) gametophytes
What is a Sporophyte
A sporophyte is the multicellular, diploid generation produced during the alteration of generations of plants and algae. It begins from the diploid zygote and produces haploid spores in sporangia by meiosis. Some organisms produce homospores while the others produce heterosporous called microspores and megaspores. Spores are germinated to produce the gametophyte. The germination of microspores produces microgametophyte and that of megaspores produces megagametophyte. During evolution, the sporophytic stage becomes dominant over the gametophytic stage. The primitive non-vascular plants like bryophytes consist of a sporophyte that completely depends on their gametophytes. In pteridophytes, gymnosperms, and angiosperms, the sporophyte is the dominant stage. The dominant sporophyte is differentiated into root, stem, and leaves as well. The sporophyte of angiosperms, consisting of a differentiated plant body is shown in figure 2.
Figure 2: The sporophyte of angiosperms
Difference Between Gametophyte and Sporophyte
Definition
Gametophyte: The gametophyte is the haploid phase of plants. It produces gametes and the zygote from which the sporophyte arises.
Sporophyte: The sporophyte is the diploid phase of plants. It produces spores which are developed into the gametophyte.
In Bryophytes
Gametophyte: The gametophyte is the dominant plant body that is independent.
Sporophyte: The sporophyte depends on the gametophyte.
In Pteridophytes and Higher Plants
Gametophyte: The gametophyte is reduced.
Sporophyte: The sporophyte is dominant.
Ploidy
Gametophyte: The gametophyte is haploid.
Sporophyte: The sporophyte is diploid.
Development
Gametophyte: The gametophyte is developed by the germination of a meiospore.
Sporophyte: The sporophyte is developed from the zygote.
Production
Gametophyte: The gametophyte is produced by meiosis.
Sporophyte: The sporophyte is produced by mitosis.
Reproduction
Gametophyte: The gametophyte reproduces sexually.
Sporophyte: The sporophyte reproduces asexually.
Products
Gametophyte: The gametophyte produces male and female gametes.
Sporophyte: The sporophyte produces microspores and megaspores.
Following Generation
Gametophyte: The sporophyte is generated by the fertilization of gametes.
Sporophyte: The gametophytes are generated by the germination of spores.
In the Life Cycle of Plants
Gametophyte: The gametophyte represents the sexual phase of the life cycle of the plant.
Sporophyte: The sporophyte represents the asexual phase of the life cycle of the plant.
Conclusion
Gametophyte and sporophyte are the two phases that occur during the alteration of generations in plants and algae. The gametophyte is considered as the sexual phase and the sporophyte is the asexual phase. The gametophyte is developed by the germination of haploid spores. Hence, it is also haploid. The sporophyte is developed from the diploid zygote that is formed during the fertilization of gametes. The gametophyte produces gametes while the sporophyte produces spores. During evolution, the sporophyte becomes dominant over the gametophyte. The sporophyte of higher plants is differentiated into root, stem, and leaves as well. However, the main difference between gametophyte and sporophyte is the number of chromosome sets or the ploidy of the plant body in each phase.
Reference:
1. “Gametophyte.” Merriam-Webster. Merriam-Webster, n.d. Web. 23 May 2017. <https://www.merriam-webster.com/dictionary/gametophyte>.
2. “Sporophyte.” Merriam-Webster. Merriam-Webster, n.d. Web. 23 May 2017. <https://www.merriam-webster.com/dictionary/sporophyte>.
3. “Sporophyte.” Plant Sciences. Encyclopedia.com, n.d. Web. 23 May 2017. <http://www.encyclopedia.com/plants-and-animals/botany/botany-general/sporophyte>.
Image Courtesy:
1. “Marchantia polymorpha gametophytes” By Plantsurfer – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Acer palmatum BotGartenMuenster Faecherahorn 6691” By Rüdiger Wölk (CC BY-SA 2.5) via Commons Wikimedia
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