Content Strategy Manager | Updated On - Jul 2, 2024
The term “Spore” has been derived from the Greek word ‘Spora’, which means seed. So, in general, Sporulation means Spore Formation or Seed Formation. But Spores are different from gamete in the sense of reproduction system. One gamete needs another gamete to form a zygote after fertilization whereas a spore will germinate and develop into a sporeling.
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Read Also: How do Organisms Reproduce?
What is Spore?
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A spore is a unit of sexual and asexual reproduction systems. Spore is a part of the life cycle of many plants, algae, fungi, and protozoa.
- A spore is different from a seed. A spore is unicellular, the first cell of a gametophyte whereas a seed contains a developing embryo.
- Spore always give rise to haploid gametophytes after germination while seed gives rise to diploid sporophytes.
Bacterial Spore:
- Bacterial spore is not a part of the sexual cycle.
- It is a part of survival in an adverse environment.
Fig: Bacterial Spore
Myxozoan Spore:
- Myxozoan Spores releases amoebulae into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium which develops from the amoeba.
Fig: Myxozoan Spore
Characteristics of Spores
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- Spores are usually Haploid and unicellular.
- It is produced by meiosis in the sporangium of a diploid sporophyte.
- Spores can develop a new organism by mitotic cell division.
Alternation of generation: Two gametes are fused to form a zygote which develops into a new sporophyte. The spore is newly formed and has half the DNA as the parent organism. This spore undergoes mitosis multiple times to form a gametophyte. This cycle is called the Alternation of Generations.
Spores in Tree
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- The vascular plant can form spores which are always Haploid.
- Vascular plants are either Homosporous or Heterosporous.
- Homospores are the same in size and type.
- Heterosporous are spores that are different in size and types.
- Heterosporous are two types one is Megaspore (large spore) and another is Microspore (small spore).
Read More: Vegetative propagation in plants
Spore in Fungi
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- Fungi generally produce spores which are the result of sexual and asexual reproduction.
- Fungi spores are generally haploid.
- Dikaryotic cells are the result of the fusion of two haploid gamete cells.
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Types of Spores
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- Sporangiospores: Sporangiospores are the spores that are produced by Sporangium for many fungi like Zygomycetes.
- Zygospores: Zygospores are the spores that are produced by Zygosporangium for many fungi like Zygomycetes.
- Ascospores: Ascospores are the spores that are produced by an Ascus, for many fungi like Ascomycetes.
- Basidiospores: Basidiospores are the spores that are produced by Basidium for many fungi like Basidiomycetes.
- Aeciospores: Aeciospores are the spores that are produced by an Aecium for many fungi like Rusts or Smuts.
- Urediniospores: Urediniospores are the spores that are produced by a Uredinium for many fungi like Rusts or Smuts.
- Teliospores: Teliospores are the spores that are produced by a Telium for many fungi like Rusts or Smuts.
- Oospores Oospores are the spores that are produced by an oogonium for many fungi like Oomycetes.
Spores are also classified on the basis of cell division like Meiospores and Mitospores.
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Meiospores:
- Meiospores are the spores produced by Meiosis.
- Meiospores are haploid
- Meiospore gives rise to a haploid daughter cell or a haploid individual.
- Examples: Precursor cells of Gametophytes found in many flowers and cones.
- It is found mainly in Angiosperms or Gymnosperms.
Ulva: The zoospores are produced from meiosis in the sporophytes of algae-like Ulva.
Meiospores are also classified as microspores and Megaspores.
- Microspore: (Pollen in seed plant)
When one Meiospore gives rise to a male Gametophyte, it is called a Microspore.
- Megaspore: (Macrospores)
When one Meiospore gives rise to a female Gametophyte, it is called a Megaspore.
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Mitospores:
- Mitospores are also known as Conidia or Conidiospores.
- Spores produced by Mitosis.
- They are characteristic of Ascomycetes.
- Fungi in which only mitospores are found are called Mitosporic Fungi or Anamorphic Fungi.
Spores are also classified on the basis of Mobility like
- Zoospores: These are mobile spores moves by Flagella.
- Aplanospores: These are immobile flagella but sometimes can move potentially.
- Autospores: These are immobile flagella that can not develop flagella.
- Ballistospores: Spores that are forcibly discharged as the result of an internal force from the fungal fruiting body.
Examples: - Basidiospores
- Spores from genus Pilobolus
- Statismospores: Spores that are forcibly discharged as the result of an external force from the fungal fruiting body.
Example: Puffballs.
Spores Ejection by Fungi:
- In fungi, spores are actively dispersed from their reproductive structure by forcible ejection.
- This ejection is necessary to ensure the exit of the spores.
Sample Questions Based on Spore Formation
Ques.1 : Illustrate the following with the help of suitable diagrams:
(i) Spore formation in Rhizopus.
(ii)Multiple fission in Plasmodium.(2 marks)
Ans:
(i)
(ii)
Ques. 2: (a) What is spore formation?
(b) Draw a diagram showing spore formation in Rhizopus.
(c) List two advantages for organisms to reproduce themselves through spores.(2 marks)
Ans: (a) When a slice of bread is kept in a moist dark place the spores of Rhizopus present in air settle down on the bread to form new fungus plants of Rhizopus.
(b) Spore Formation in Rhizopus
(c) Two advantages for organisms to reproduce themselves through spores are as follows:
(i) Spore formation is the faster mode of reproduction.
(ii) Offsprings that are produced are identical.
Ques.3: Name an organism which reproduces by spore formation. List three conditions
favourable for spores to germinate and grow.(2 marks)
Ans: Rhizopus reproduces by spore formation. The conditions that are favourable for the spore formation are:
(i) Cool place, (ii) Moist place and (iii) Dark place.
Ques.4: What are Carpospores?(1 mark)
Ans: Spores that are produced by Carposporophytes, characteristic of Red Algae are Carpospores.
Ques.5: What are Tetraspores?(1 mark)
Ans: Spores that are produced by tetrasporophytes, characteristic of Red Algae, are Tetraspores.
Ques.6: What is the classification of Parasitic Fungal Spores?(1 mark)
Ans: Parasitic Fungal Spores are classified into internal spores which germinate within the host and external spores, also called environmental spores, released by the host to infect other hosts.
Ques.7: What are Mitospores?(1 mark)
Ans: Mitospores-
- Mitospores are produced by mitosis.
- Mitospore is also known as Conidia.
- They are mainly found in Ascomycetes.
Ques.8: What is Buller’s drop?(1 mark)
Ans: The forcible discharge of single spores known as Ballistospores which helps in the formation of a small drop of water is called a Buller Drop.
Ques.9: What are Hydrophobins?(1 mark)
Ans: Hydrophobins are one kind of specialized mechanical and physiological mechanism of spore ejection for many fungi.
Ques.10: What are Puffballs?(1 mark)
Ans: Puffballs are fungi other than Ballistospores that eject their spores by external forces. They are dust-like in appearance and they get emitted when the mature fruitbody is impacted or it bursts.
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