Slime Moulds - Acellular

Description:

Acellular slime moulds are commonly found on dead and decaying leaves, twigs, logs of wood and other vegetable matter. They prefer to grow mostly in damp areas.

A free living thalloid body of the acellular slime mould is called plasmodium. Plasmodium often possess a number of branched veins. Chief mode of nutrition is saprotrophic, absorbing organic nutrients from the decaying organic matter.

Under unfavourable conditions plasmodium divides into two types of perennating structures. Perennating structure are those structures which are used for surviving from year to year by vegetative means. The two types of perennating structures are −

• Cyst − Plasmodium divides into small multinucleate fragments and each fragment secretes thick covering to form cyst.

• Sclerotium − The whole plasmodium secretes a thick covering around itself called sclerotium.

Life Cycle of Slime Moulds

• Sporangia − When plasmodium reaches certain stage of maturity or food supply is exhausted, the contents of plasmodium concentrate at one or more places which grown into sporophores.

• Spores − The numerous diploid sporangium undergo meiotic division. The multinucleated forms tiny segments. Each segment secretes a cell wall to form spore.

• Germination and Sexual Reproduction − The spores germinate when water is available and forms swarm cells. This swarm cell fuses with another cell to form zygote.