Scope & Tips of Rainbow Trout Farming in India

REPRODUCTION: 

1. Reproduction is the formation of new individuals having all the characteristics typical of a species.

 2. The fungi reproduce by means of asexual and sexual reproduction. 

3. The union of two nuclei characterizes sexual reproduction. 

4. Reproduce either sexually (by meiosis) or asexually (by mitosis).

I. VEGETATIVE REPRODUCTION 

 In fungi the following are the common methods of Vegetative reproduction. 

1. Fragmentation of mycelium: 

 Mycelial fragments from any part of the thallus may grow into new individuals when suitable conditions are provided. Eg. only mycellial fungi. 

2. Fission of unicellular thalli: 

 It is also known as transverse cell division. Reproduction by the method of fission is are in fungi. 

 Fission is simple splitting of cells into two daughter cells by constriction and the formation of a cell wall Eg. Yeast.

3. Budding 

 Budding is the production of a small outgrowth (bud) from a parent cell. As the bud is formed, the nucleus of the parent cell divides and one daughter nucleus migrates into the bud.

 The bud increases in size, while still attached to the parent cell and eventually breaks off and forms a new individual.

 It is common in yeasts.(Saccharomyces sp. ).

II. Asexual Reproduction 

 It occurs through spores. 

 Spores produced during asexual reproduction in fungi are formed by mitotic division and thus termed, mitospores.

Mitospores: 

Spores are formed during mitotic division that is known as Mitospores. The spores produced asexual means are: 

a. Sporangiospores 

b. Conidia 

c. Chlamydospores

a. Sporangiospores: 

 Sporangiospores may be motile (zoospores) or nonmotile spores (aplanospores). 

 These spores are produced in lower fungi, which inhabit aquatic or moist terrestrial substrates, eg. Saprolegnia, pythium. 

 Sporangiospores are formed in globose or sac-like structure called sporangium. 

 When aplanospores are dry then are dispersed by wind currents.

Zoospore: 

 It is an asexually produced spore, which is motile by means of flagellum or flagella.

 Normally, zoospores are uninucleate and haploid. 

 The zoospores are provided with one or two flagella for its movement in the surrounding film of water.

b. Conidiospores

  Generally the term 'conidia'is used for any asexual spores other than sporangia and spores formed directly by hyphal cells. 

 Conidiospores or conidia (sing. Conidium) are asexual reproductive structures borne on special spore bearing hyphae conidiophores.

 Conidiophores are also known as sporophores.

c. Chlamydospores 

 Chlamydospore is a thick-walled thallic conidium that generally function as a resting spore. 

 Terminal or intercalary segments or mycelium may become packed with food reserves and develop thick walls.

  They are the important organs or asexual survival in soil fungi. 

 When chlamydospores are found in between fungal cells they are called 'intercalary chlamydospores'.

 These structures are known as chlamydospores. e.g. Fusarium, Mucor racemosus, Saprolegnia.