Reproduction in lichens for +3 zoology students

REPRODUCTION   IN   LICHENS

- Commonly lichens produced by vegetative , asexual and sexual methords of reproduction.

A. VEGETATIVE REPRODUCTION

a) BY FRAGMENTION

- Death and decay of older parts of the thalus produce smaller pieces.

- This pieces give rise to new thalus.

- In sometime the broken poritin are born in other substrated by wind.

- Each flagelats contains algal and fungal or getting a suitable substrated , each portion give rise to a new thallus.

 b) BY SOREDIA

- It is the most common methord of vegetative reproduction.

- Soredia are dispersed by wind sometime they form a massive cating on the thallus called as soredia dust.

-Each soredium contain fungal hyphae and algal cell , on getting suitable substratun give rise to new lichen thallus.

 c) BY ISIDIA

- Isidia are broken off from the parent thallus and dispresed to other substrate.

- Each isidium contain fungal and algal componets, so they get suitable substratum give rise to new lichen thalli.(singular) 

ASEXUAL  REPRODUCTION

- Certain lichens may also reproduce asexual reproduction.

- It occurs by formation of spores.

- The fungal and algal parent are not involves in production of spores.

- Asexual spores are know as pycindia . It is conical flask shaped structure.

- Each pycinidium opens to the small pore know as ostiole.

- The pycnidial wall is made up of sterite fungal hyphae.

-In pychidium several fertile hyphae originate which produce several pycnidiospores from the tips.

- Pycnidiospores is a small and nonmotile structure.

- After falling on suitable substratum pycnidiospores germinated and contact with alga, they develop a new lichen.

SEXUAL  REPRODUCTION

- Sexual reproduction is only the function of the fungal partner.

- Algal partner is not involved in the process.

- The sexual reproduction sex organ is also lichens are produced is given below.

SEX  ORGAN

a. Male reproductive organ

-  The flask-shaped structure also called as spermogoia.

-It is a flask shaped cavity embeded in the thallus and open into out side by a opening called ostiole.

- The fertile hyphae in the cavity of the spermogonium a minute rounded cell at its tip.

- This mall cells is called as spermatia.

b. Female reproductive organ

- The female sex organ is called as carpogonium.

- It develop from hypha deep in the algal layer.

- It is a long multicellular hypha and the basal portion is coild to from the oogonium.

-And the upper part is called the trichogyne.

FERTILISTION

- At the point of contact between spermatia(male) and trichogyne (female).

- The wall dissolves and content of spermatium passes into trichogyne through a pore.

- The male nucleus passes down word and fews with the nucleus in the oogonium resulting in fertilization and a new lichens produce.

ECONOMIC  IMPORTANCE  OF  LICHENS

- Lichens have several uses,

1. food for human and animals.

2. Also use for medical and health product.

3. For prepation of colours.

4.Lichens for litmus preparation.

5. Prepation for perfumes.

6. Lichensin asethetic uses.

      Prof.- Dr ramakant pradhan 

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