In this article we will discuss about vegetative structures of alternaria.
1. Mycelium of the fungus is intercellular or intracellular.
2. Light-brown coloured hyphae are well-branched, septate, and each cell is multinucleate (Fig. 111).
3. Haustoria are absent.
Fungus reproduces only be asexual reproductive bodies called conidia, which show following characters:
1. These are present (Fig. 112) terminally on conidiophores.
2. Each conidiophore is a multicellular, short or elongated, dark-coloured structure.
3. Each cell of the conidiophore is multinucleate.
4. Each conidium is multicellular, obovoid, elliptical or spindle-shaped structure.
5. Some 5-15 transverse and longitudinal septa are present in each conidium.
6. The colour of the conidia is yellowish brown or dark brown.
7. Conidia may also be present in chains, as in Alternaria tenuis.
8. In moist conditions, conidia germinate (Fig. 113) with the help of 5 to 10 germ tubes.