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General characteristic features
• Majority of fungi are made up of thin, filamentous branched structures called hyphae. A number of hyphae get interwoven to form mycelium. The cell wall of fungi is made up of a polysaccharide called chitin (polymer of N-acetyl glucosamine).
• The fungal mycelium is categorised into two types based on the presence or absence of septa (Figure 1.19). In lower fungi the hypha is aseptate, multinucleate and is known as coenocytic mycelium (Example: Albugo). In higher fungi a septum is present between the cells of the hyphae. Example: Fusarium.
• The mycelium is organised into loosely or compactly interwoven fungal tissues called plectenchyma. It is further divided into two types prosenchyma and pseudoparenchyma. In the former type the hyphae are arranged loosely but parallel to one another In the latter hyphae are compactly arranged and loose their identity.
• In holocarpic forms the entire thallus is converted into reproductive structure whereas in Eucarpic some regions of the thallus are involved in the reproduction other regions remain vegetative. Fungi reproduce both by asexual and sexual methods. The asexual phase is called Anamorph and the sexual phase is called Teleomorph. Fungi having both phases are called Holomorph.
In general sexual reproduction in fungi includes three steps 1. Fusion of two protoplasts (plasmogamy) 2. Fusion of nuclei (karyogamy) and 3. Production of haploid spores through meiosis. Methods of reproduction in fungi is given in Figure 1.20.
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