Q.Differentiate Oidium and Chlamydospore.

Oidia are thin-walled, short-lived fragmentation spores that germinate at once, whereas chlamydospores are thick-walled resting spores adapted to survive stress before germinating.

Both are asexual means of fungal propagation formed directly from the vegetative (somatic) hyphae, but they serve different biological purposes:

Oidium:

• Formed by fragmentation (disarticulation) of a hypha into a chain of small, thin-walled, uninucleate or few-nucleate segments.
• Thin-walled, not built to resist desiccation or adverse conditions.
• Each oidium behaves like a spore and germinates directly and quickly under favourable conditions to form a new mycelium, without needing a dormant/resting period.

Chlamydospore:

• Formed when a cell (or a short segment) of the hypha rounds off, accumulates dense reserve food material, and develops a thick, resistant wall around itself, while the rest of the hypha may disintegrate.
• Thick-walled and metabolically inactive — specifically adapted to withstand unfavourable conditions such as desiccation, cold, or nutrient scarcity. …