What Is the Difference Between Unilocular and Plurilocular Sporangia in Structure and Function
You may be surprised to know that oxygen for breathing for aquatic animals is produced by algae. Did you know there are so many varieties of algae? Some of the algae are red-colored, some of the algae are brown-colored, and some of the algae are green due to the presence of different pigments. Ectocarpus is also one of the brown algae. Both types of sporangia are present in ectocarpus unilocular and plurilocular.
What is Ectocarpus?
Ectocarpus is a type of fungus. It is a brown alga and has a filament known as filamentous algae. It is a type of marine algae found all over the world. There are two main species of Artocarpus - Ectocarpus siliculosus, and Ectocarpus fasciculatus. Its thallus is branched and has erect and prostrate branches. Cells of filament are uninucleate and cylindrical. Their cell wall is composed of cellulose and pectin. These algae are brown-colored due to the presence of a pigment called fucoxanthin.
What is Sporangia?
A sporangium is a structure present in fungus, algae, certain plants, and some other organisms. These structures make and store spores.
Reproduction In Ectocarpus
There are both types of reproduction in Artocarpus - asexual and sexual.
Asexual Reproduction - This type of reproduction takes place by biflagellated zoospores. Now, these zoospores may be haploid or diploid. If spores are produced in unilocular sporangia, then haploid spores are produced. These spores are produced by meiotic division. These zoospores are uninucleated and pyriform. Plurilocular sporangia produced diploid spores by mitosis. The plurilocular sporangia do not play any role in the alternation of generation.
Sexual Reproduction - There may be the isogamous or anisogamous type of sexual reproduction in ectocarpus. Generally, ectocarpus is isogamous and homothallic but some of the ectocarpus may be heterothallic and anisogamous. Gametes are produced in plurilocular gametangia. The gametogenesis divides by mitotic division and forms hundreds of cells. Then after these cells transform into biflagellated gametes. Then these gametes release through gametangium. Gametes fused to form a zygote, and later this zygote developed into a sporophyte containing unilocular and plurilocular sporangia.
What is Unilocular Sporangia?
Unilocular sporangia are single-cell, enlarged structures produced by brown algae that undergo meiotic division to make zoospores. The unilocular sporangia develop small branchlets. Then meiotic division occurs along with mitotic division to make a large number of zoospores. These zoospores are also known as meio zoospores because they are produced by meiotic division.
What are Plurilocular Sporangia?
These plurilocular sporangia are also produced by brown algae and developed from terminal cells of branchlets. Around 5-12 cells are produced from plurilocular sporangia. And the temperature required for sporangia production is 13-16°C.
Difference Between Unilocular and Plurilocular Sporangia
Important Questions
1. What is the function of plurilocular sporangia?
Ans: It is a multi-chambered sporangium that undergoes mitotic division to make zoospores. Then these spores after fusion make zygote which further makes sporophytes. These spores are also known as mitospores.
2. In which of the following algae do unilocular sporangia occur?
Ans: Unilocular sporangia are found in ectocarpus which is a brown alga. This alga produces unilocular sporangia generally at 13°C. And plurilocular sporangia at 19°C.
3. Is a zygote haploid or diploid?
Ans: A zygote is always diploid as it is formed by the fusion of male and female haploid gametes, a process known as fertilization.
Interesting Facts
There are more than 4 lakh varieties of algae
There are more algae in oceans than stars in the universe, for eg. If we take a drop of water it would contain more than 1000 algae in it
Algae is a very rich source of protein and vitamins.
Many space travelers use algae as food supplements
Algae is also used as an alternative to fossil fuel
All plants of the present time evolved from algae.
Key Features
In this article, we studied ectocarpus which is a type of marine brown algae
They reproduce by both asexual and sexual methods.
Sporangia are the structures found in ectocarpus and other algae, and fungus for asexual reproduction. There are two types of sporangia, unilocular sporangia, and plurilocular sporangia.
Sporangia are the structures that produce and store spores.
Gametogeniaise the structures that produce gametes for sexual reproduction.
Practice Questions
What are the three types of asexual reproduction in plants?
Which algae is found in freshwater?
What is plurilocular gametangia.?
What are the largest algae?
Which algae is rich in protein?
FAQs on Difference Between Unilocular And Plurilocular Sporangia in Algae
1. What is the difference between unilocular and plurilocular sporangia?
The main difference between unilocular sporangia and plurilocular sporangia is that unilocular sporangia have a single chamber and produce spores by meiosis, while plurilocular sporangia have many chambers and produce spores by mitosis.
- Unilocular sporangium: Single cavity; spores formed after meiotic division; usually involved in sexual reproduction.
- Plurilocular sporangium: Many small chambers (locules); spores formed by mitotic division; usually involved in asexual reproduction.
- Commonly found in brown algae (Phaeophyceae) such as Ectocarpus and Laminaria.
2. What is a unilocular sporangium?
A unilocular sporangium is a single-chambered spore-producing structure that forms haploid spores through meiosis.
- Develops from a single cell.
- Undergoes meiotic division to produce numerous haploid meiospores.
- Typically associated with the sexual phase in brown algae.
- Example: Seen in the sporophyte of Ectocarpus.
3. What is a plurilocular sporangium?
A plurilocular sporangium is a multicellular spore-producing structure with many chambers that produces spores by mitosis.
- Divided into many small compartments called locules.
- Each locule forms one spore through mitotic division.
- Generally involved in asexual reproduction.
- Common in brown algae like Ectocarpus.
4. How are spores formed in unilocular and plurilocular sporangia?
Spores in unilocular sporangia are formed by meiosis, whereas spores in plurilocular sporangia are formed by mitosis.
- Unilocular sporangium: A diploid nucleus undergoes meiosis → produces haploid meiospores.
- Plurilocular sporangium: Cells divide by mitosis → each locule forms one spore.
- This difference reflects their roles in sexual vs asexual reproduction.
5. In which organisms are unilocular and plurilocular sporangia found?
Unilocular and plurilocular sporangia are mainly found in brown algae (class Phaeophyceae).
- Common genera include Ectocarpus, Laminaria, and Dictyota.
- These structures are part of their complex life cycles.
- They help in alternation between sporophytic and gametophytic phases.
6. What is the function of unilocular sporangia?
The function of a unilocular sporangium is to produce haploid spores for sexual reproduction.
- Undergoes meiotic division.
- Produces numerous haploid meiospores.
- These spores grow into the gametophyte generation.
- Ensures genetic variation through meiosis.
7. What is the function of plurilocular sporangia?
The function of a plurilocular sporangium is to produce spores for asexual reproduction.
- Forms spores through mitotic division.
- Each locule produces one spore.
- Helps in rapid multiplication of the organism.
- Maintains the same ploidy level as the parent.
8. Why is meiosis associated with unilocular sporangia?
Meiosis is associated with unilocular sporangia because they are involved in producing haploid spores from a diploid sporophyte.
- The diploid nucleus undergoes meiotic division.
- This reduces chromosome number from diploid to haploid.
- Ensures genetic recombination and variation.
- Forms part of the alternation of generations in brown algae.
9. How can you identify unilocular and plurilocular sporangia under a microscope?
Unilocular sporangia appear as single large chambers, while plurilocular sporangia appear divided into many small compartments under a microscope.
- Unilocular: One spherical or oval cavity filled with spores.
- Plurilocular: Many small rectangular or cubical locules arranged side by side.
- Plurilocular structures look multicellular compared to the single-cavity unilocular type.
10. What are the key points to remember about unilocular and plurilocular sporangia?
The key points are that unilocular sporangia are single-chambered and meiotic, while plurilocular sporangia are multi-chambered and mitotic.
- Unilocular sporangium: Single locule, meiosis, sexual reproduction, haploid spores.
- Plurilocular sporangium: Many locules, mitosis, asexual reproduction, same ploidy as parent.
- Both are characteristic features of brown algae life cycles.
