Reproduction in Fungi || Vegetative Reproduction

 Reproduction in Fungi

Reproduction

Reproduction is the biological process by which new 'offspring' individual organisms are produced from their "parents". Reproduction is a fundamental feature of all known life; each  individual organism exists as the result of reproduction.

 The known methods of reproduction are

broadly grouped into two main types: sexual and asexual.

Types of Fungul Reproduction

Fungi also have 3 type of reproduction

         1. Vegetative

         2. Asexual

         3. Sexual

    1. Vegetative Reproduction 

It is the type of reproduction which involves the somatic portion of the fungal thallus where new individuals are formed without the production of seeds or spores by meiosis or syngamy

FIGURE : THE VEGETATIVE HYPHAE 

 Vegetative Reproduction takes place by following methods :-

                 1. Fragmentation

                 2. Fission

                 3. Budding

                 4. Oidia

                 5. Chlamydospores

                 6. Rizomorphs

                 7. Sclerotia

1. Fragmentation

In fragmentation, which may result from accidental severing of the mycelium into bits or fragments or by mechanical injuries or otherwise, the mycelium breaks into segments of hyphae. Each segment by further division of cells and apical growth develops into a new mycelium under

favorable conditions.

2. Fission 

In unicellular fungi like the fission yeast, the single cell multiplies by fission. Here, the parent cell elongates and divides transversely into two daughter cells. First, the nucleus divides, followed by the division of the cytoplasm and wall formation, thus dividing the parent cell into two.

3. Budding

In budding yeast, the cells reproduce by a process called budding. Here, the parent cell puts out a small outgrowth which is called a bud. The bud gradually enlarges and finally gets separated from the parent cell by a cross wall. This end develops into new individual yeast. Sometimes the bud

before separation from the parent cell may produce a new bud and in this way a chain of buds may be produced which finally get separated.

Figure: Budding

4. Oidia 

In some filamentous fungi, the hyphae break up into individual cells which are called oidia or arthrospores. The cells become rounded or oval in shape and appear like the beads of a rosary. Each oidium or arthrospore develops into a new mycelium.

5. Chlamydospores

The chlamydospores are one-celled fragments, which function as perennating bodies. They are formed either singly or in chains in the vegetative hyphae. The chlamydospores develop thick, resistant walls and accumulate food materials and thus help the fungus to tide over

unfavorable conditions. With the return of favorable conditions each chlamydospores develops into a new mycelium. 

e.g. Mucor, Fusarium.

6. Rizomorphs

In some higher fungi, several hyphae may become interwoven to form rope-like structures called rhizomorphs. Under favourable conditions, they resume growth to give rise to new mycelia. These fine, root-like strands, usually dark brown in colour called rhizomorphs, serve as a means of

perennation.

7. Sclerotia

In some cases, as in Claviceps, the hyphae become interwoven to form a compact mass and get surrounded by a hard covering or rind. Such structures are called SCLEROTIA. They remain dormant under unfavourable conditions and germinate into new mycelia on the return of

favourable conditions. They serve as a means of perennation and vegetative propagation. They may be rounded, cylindrical. Cushion-shaped or irregularly shaped with a dense mass of thick

walled hyphae. The hyphae form a compact, pseudoparenchymatous tissue. With the return of favourable conditions a sclerotium germinates to form a new mycelium.

e.g. Claviceps (ergot).

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