Kingdom Fungi

These are eukaryotic organisms with cell walls made up of chitin. They do not perform photosynthesis (heterotrophs). They may be unicellular (yeast) or filamentous (most fungi). They feed on decaying organic materials. Such a mode of nutrition is called saprophytic. Some fungi live in a symbiotic relationship with other organisms (lichens), while some are parasites as well.

Examples: mushrooms (Agaricus), green mould (Penicillium), and smut (Aspergillus).

Fungi

1. Aim: To observe the growth and structure of fungi on a moist piece of bread or bhakri over a few days and study it under a microscope.

2. Requirements: A moist piece of bread or bhakri, a clean, airtight container with a lid, a microscope, glass slides and cover slips, a dropper, water, forceps, and stain (such as lactophenol cotton blue).

3. Procedure

• Preparation: Place a moist piece of bread or bhakri in a clean, airtight container, ensuring it remains moist but not overly wet.
• Incubation: Seal the container and leave it undisturbed in a warm spot for 2-3 days.
• Growth Observation: Check for cotton-like tufts of fungal growth on the bread surface after 2-3 days.
• Sample Collection: Use forceps to gently extract a few threads of fungal mycelium.
• Slide Preparation: Put the mycelium on a glass slide, add a drop of water or stain, and cover with a slip, avoiding air bubbles.
• Microscope Observation: View under the microscope, starting with low magnification and increasing to examine the structure of hyphae and spores.

4. Conclusion: The experiment shows that fungi, like mould, thrive on moist bread or bhakri in warm, humid conditions. Under a microscope, the fungi appear as fine, thread-like structures called hyphae, with visible spores. This highlights the growth and structure of common bread mould.

1. Meaning - Heterotrophic organisms; body made of thread-like hyphae; network of hyphae = mycelium; cell wall made of chitin; grow in warm and humid places; except yeasts, all are multicellular.

2. Nutrition - Can be saprophytic (feed on dead matter), parasitic or symbiotic (as lichens and mycorrhiza).

3. Reproduction - Asexual by spores (conidia, zoospores, aplanospores); sexual reproduction involves 3 steps - plasmogamy → karyogamy → meiosis; Ascomycetes and Basidiomycetes undergo a dikaryotic stage.

4. 4 Classes of Fungi:

• Phycomycetes - Mycelium aseptate, coenocytic; spores endogenous in sporangium. e.g. Rhizopus, Albugo
• Ascomycetes (Sac fungi) - Asexual spores = conidia; sexual spores = ascospores in ascus. e.g. Aspergillus, Neurospora
• Basidiomycetes - No asexual spores; sexual spores = basidiospores (exogenous). e.g. Agaricus, Ustilago, Puccinia
• Deuteromycetes (Imperfect Fungi) - Sexual form unknown; saprophytic/parasitic. e.g. Alternaria, Colletotrichum

5. Classification basis - Based on morphology, mode of spore formation and fruiting bodies.

6. Important examples - Puccinia (wheat rust), Penicillium (antibiotic), Agaricus (mushroom), Neurospora (genetic research).