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FUNGI : INTRODUCTION

Fungi

Etymological meaning :   Derived from latin ( fungus ) meaning mushroom . 
Fungi ( singular . fungus = mushroom ) are eukaryotic organisms which are grouped in a distinct kingdom within an eukaryote . The kingdom fungi ( mycota ) includes an enormous variety of organisms  ranging from unicellular yeasts to the multicellular mushrooms like as Black mould  , Penicillin , Aspergillus , etc . All the organisms of the kingdom Fungi belonging to the domain Eukarya are collectively referred to as ' Eucomycota ' or ' True fungi '. It is a large kingdom of over 1,00,000 species . All the saprophytes are included in the kingdom mycota . 

CHARACTERSTICS OF FUNGI : 

1. Fungi are achlorophyllous non-vascular eukaryotic multicellular, spore bearing organisms except yeast (a unicellular fungus).

2. The vegetative body of the fungi is made up of microscopic long, branched filaments or threads called hyphae.  Hyphae can grow and form a network of hyphal mass called a mycelium.

3. Morphologically yeasts are unicellular fungi that do not produce hyphae while molds are multicellular and filamentous. 

4. The hypha may be aseptate and multinucleate i.e. coenocytic or septate. The hyphal cell of septate mycelium may contain only one (monokaryotic), two (dikaryotic) or more nuclei.

5. The septa between the cell may have different types of pores, namely micropore, simple pore or dolipore.

6. Fungi lack chloroplast and have a heterotrophic mode of nutrition. Mostly fungi are saprophytic (gets energy from dead and decaying matters). However some fungi are parasitic (lives in a host, attack and kill) or symbionts (mutually beneficial) . 

7. They have cell walls which are made up of chitin C8H13O5N)n. (a polymer of N-acetyl glucosamine t.e. NAG or fungal cellulose. So, they are stained with cotton blue.

8. Their cell membrane consists of unique sterol and ergosterol, 

9. The reserved food material of fungi is glycogen and oil globules.

10. The unicellular fungi are holocarpic (whole cell body is converted into reproductive unit e.g. (Synchytrium) while many others are eucarpic fungi (only a part of the mycelial body converted into reproductive unit e.g. Pythium).

11. They reproduce by vegetative, asexual and sexual methods.

12. Vegetative reproduction takes place by fragmentation ( Mucor), budding (Saccharomyces) and fission (Saccharomyces).

13. Asexual reproduction takes place by different types of spores like zoospores (Synchytrium), conidia ( Aspergillus ) , oidia (Alop, chlamydospore (Fusurium), etc. The spores are typically non motile which may be unicellular (  Aspergillus) or multicellular   (Alternaria) 

14. Their sex organs are usually unicellular non-jacketed.

15. Pheromone is a chemical substance produced by fungi, which stimulates to the sexual reproduction between male and female fungi cells. 

16. Sexual reproduction takes place by gametic copulation, gamete-gametangium copulation, gametangium copulation, somatic copulation and spermatization

17. Sexual spores are oospores, zygospores, ascospores, basidiospores, etc.

18. There is no embryonic stage in fungi.

19 .Fungi exhibit the phenomenon of alteration of generation. They have both haploid and diploid stages.

20. The growth rate of fungi is slower than that of bacteria and optimum temperature of growth for saprophytic fungi is 20°C-30°C while 30°C-37°C for parasitic fungi.