Myxomycota

Myxomycota
Presented by
vivek kumar
M.Sc Microbiology
Bangalore university

Introduction
The myxomycota differs from true fungi because their
vegetative body consists of only protoplast bounded by
membrane and devoid of cell wall and also for their
phagotropic mode of nutrition .
Economically , they have little importance but are very useful
as experimental tools in the study of molecular biology ,
biochemistry , cytology , genetics etc .

Some important characterstics of
the division Myxomycota
 Common name:- Plasmodial slime molds.
Habitat:- terrestrial , moist decaying vegetation.
Growth habit:- multinucleate single-cell
plasmodium.
Cell wall- none.
The mode of nutrition is phagotropic.
The mode of reproduction by producing spores within
sporangia .
They are either holocarpic or eucarpic .
They exhibit variable coloration.

The division myxomycota includes the organisms like celluar
slime molds, the plasmodial slime molds and the net slime
molds.
 De Bary (1887), the founder of plant pathology and also the
founder of modern mycology , termed the group mycetozoa
(mykes - fungus and zoon-animals) i.e, fungus animal due to
presence of there naked cell and phagotropic .
This was followed by different scientists for long time:-
 Macbride (1899) was the first to name the group as
Myxomycetes .
 Martin (1960) also treated slime molds as myxomycetes
under fungi.

Olive (1975) classified the group under the kingdom
protista and divided them into seven classes:-
1) Protosteliomycetes .
2) Ceratomyxomycetes .
3) Dictyosteliomycetes .
4) Acrasiomycetes .
5) Myxomycetes .
6) plasmodiophoromycetes and
7) labrinthulomycetes .
 Later , hawksworth (1983) kept the seven classes under
the division myxomycota of the kingdom fungi .

We followed the classification of Ainsworth who
placed them within the division Myxomycota .

Class- Acrasiomycetes
Acrasiomycetes are commonly known as cellular or amoeboid
slime molds , they are found in the upper layer of humus in
forests and also in cultivated lands.
The characteristics features are:-
Somatic phase commonly consists of amoeboid cells or
myxamoebae.
Myxamoebae aggregate to form a pseudoplasmodium which
develops fruit body.
Spore wall contains cellulose.
Both sexual and asexual reproduction takes place.
Lack of flagellated cells .

Class - Hydromyxomycetes
 They are commonly aquatic and saprophytic.
The characteristic features are:-
The thallus consist of uninucleate spindle shaped cells ,
forming extensive filaments.
The filaments are tabular and form net-like structure , the
net plasmodium.
Reproduction by cyst formation, zoospore formation or by
congregation.

Class- Myxomycetes
 This group is commonly known as true slime molds or
plasmodial slime mold . They are commonly found in damp
places , especially on old wood and other decomposing plant
parts.
The characteristics features are:-
1) The vegetative body is a free – living plasmodium.
2) They feed on yeast cells , protozoa , fungal spores and
other substance.
3) Reproduction takes place by asexual and sexual means.
 Asexual reproduction:- Asexual reproduction takes place
by fragmentation of plasmodium or binary fission in
myxamoebae.

Sexual reproduction:- Sexual reproduction takes place by
fusion between flagellated zoospores or myxamoeba to form
zygote , from which multinucleate plasmodium develops by
mitotic divisions. They develops different types of
frutification.

Class – Plasmodiophoromycetes
 This group is commonly known as endo-parasitic
slime molds.
 They are obligate parasite , grow on algae ,
aquatic fungi and higher plants (commonly in
roots).
The characteristic features are:-
 Members of this class are obligate parasites of
fresh water algae , aquatic fungi and higher
plants (commonly in the roots).
 Somatic body consists of a necked holocarpic
plasmodium .

 Plasmodia are of two types in their life cycle :
sporangiogenous plasmodium (from sporangia)
and cytogenous plasmodium (gives rise to cysts
i.e, resting spores).
 Zoospores biflagellate having unequal flagella of
whiplash type , situated in opposite direction the
shorter one in anterior and longer one in
posterior side.
 Some plasmodiophora brassicae causes club root
of curcifer , spongospora subterranea causes
powdery scab of potato.

Reference
 C.J.ALEXOPOULOS , C.W.MIMS AND M.BLACKWELL ;
(1907-1986) ; INTRODUCTORY MYCOLOGY ;
Pg no.- 770,775-803 .
 RS MEHROTRA ,KR ANEJA; (1990);
AN INTRODUCTION TO MYCOLOGY;
pg no.- 76-106.

Myxomycota

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Myxomycota

Similar to Myxomycota (20)

More from microbiology Notes

More from microbiology Notes (20)

Recently uploaded

Recently uploaded (20)

Myxomycota