ADVERTISEMENTS:
In this article we will discuss about the features and significance of chytridiomycetes.
Salient Features of Chytridiomycetes:
The members of the class Chytridiomycetes, commonly called chytrids, are mostly aquatic, but a few species occur on the soil as saprophytes and some as parasites on many land plants.
The important features of this class are:
ADVERTISEMENTS:
ADVERTISEMENTS:
(i) Most of the members are unicellular, but some advanced taxa form short chains of cells which are attached to the substratum with the help of rhizoids. Some forms possess undeveloped mycelium.
(ii) Chitin and glycan are the main constituents of the cell walk
(iii) In unicellular forms the thallus is holocarpic (whole vegetative thallus transforms into one or more reproductive structures), whereas in filamentous forms it is eucarpic (some part of the vegetative thallus transforms into reproductive structure, while the rest remains vegetative).
The members of the class may be epibiotic (reproductive bodies present on the host’s surface) or endobiotic (live completely within the cells of the host) and monocentric (having only a single reproductive structure) or polycentric (having more than one reproductive structures).
ADVERTISEMENTS:
(iv) The thallus is coenocytic but sex organs are separated from vegetative part by a septum.
(v) Asexual reproduction takes place with the help of zoospores which are posteriorly uniflagellate. The flagellum is of whiplash type. Zoosporangia are spherical or pear-shaped and inoperculate or operculate.
(vi) Planogametes are also posteriorly uniflagellate.
(vii) The zygote is formed by the fusion of planogametes and it is transformed into a resting spore which produces zoospores on germination.
Significance of Chytridiomycetes:
(i) Some of the soil-inhabiting Chytridiomycetes attack the underground as well as aerial parts of the higher plants and cause diseases which are of great economic significance. For example, Synchytrium endobioticum causes black wart disease of potato; Urophlyctis alfalfae causes crown wart of alfalfa (Medicago); and Physoderma maydis causes brown spot disease of maize (Zea mays).
(ii) Many chytrids indirectly harm humans and animals. They parasitize and destroy the phytoplanktonic forms of algae that form an important link in food chain of aquatic ecosystems.
(iii) Various species of Allomyces and Blastocladiella have been found to be valuable research tools in studying morphogenesis.
(iv) Species of Coelomomyces (C. anophelescia) are endoparasites on mosquito larvae and can be utilized for the biological control of the mosquito (Anopheles spp.), which is an important vector for the spread of malaria in human beings.
ADVERTISEMENTS:
(v) Members of Blastocladiales and Monoblepharidales generally appear to function as decomposers of detritus in the aquatic and soil ecosystems.
