Some Useful Terms
- It looks like a root.
- It is made by higher fungal hyphae.
- It is made in adverse condition.
- Rhizomorph is brown in color.
- It is rigid.
- Pseudoparenchyma is absent.
- g. Armillaria mellea.
A naked multinucleate mass of protoplasm that moves and feeds in an amoeboid fashion such as the somatic phase of Myxomycota. It is a jelly like structure and comes after fertilization.
Mycelium is the vegetative part of a fungus consisting of a mass of branching, thread-like hyphae. It may be minute, forming a colony that is too small to see, or it may be extensive.
- The mycelium makes up the thallus, or undifferentiated body, of a typical fungus.
- Through the mycelium, a fungus absorbs nutrients from its environment.
- Mycelium is vital in terrestrial and aquatic ecosystems for their role in the decomposition of plant material. They contribute to the organic fraction of soil, and their growth releases carbon dioxide back into the atmosphere.
A hypha (plural hyphae) is a long, branching filamentous structure of a fungus. In most fungi, it is the main mode of vegetative growth, and are collectively called a mycelium.
- A hypha consists of one or more cells surrounded by a tubular cell wall.
- Unlike the lower fungi, the higher fungi have septum in their hyphae.
Septate – Aspergillus
Aseptate – Mucor
- Septa are usually perforated by pores large enough for ribosomes, mitochondria and sometimes nuclei to flow between cells.
Holocarpic fungi are those in which the entire thallus is differentiated into a reproductive body when mature. Hence, the vegetative and reproductive phase can never occur at the same time.
Most of the fungi are eucarpic. Here only a part of the thallus is involved in the development of reproductive organs and remaining thallus remains vegetative. In eucarpic fungi, vegetative and reproductive phases exist at the same time.
E.g. Saccharomyces cerevisiae
Homothallism is the condition in which one individual originating from a single asexual spore is capable of forming zygospores independently i.e. having male and female reproductive structures on the same thallus. Here, the opposite sexual functions are performed by different cells of a single mycelium.
Examples: Aspergillus nidulans
Heterothallism means two different individuals contribute nuclei to form a zygote.
Or, it is defined as the condition in which Zygospore formation takes place only when mycelia arising from asexual spores of two genetically different mating types (+) and (-), are allowed to interact.
Examples of heterothallism are included for Saccharomyces cerevisiae, Aspergillus fumigatus, Aspergillus flavus, Penicillium marneffei and Neurospora crassa.
A cycle in which plasmogamy, karyogamy and haplodization take place but not at a specific line or at specified points in the life cycle of an organism. Some fungi do not go through a true sexual cycle as we defined it but may derive the benefits of sexual reproduction through this process.