fungi: life cycle of

Other life cycle patterns differ from this four-stage cycle in that different reproduction mechanisms and physiology characteristics are present, esp. for non-moldy fungi (such as wood rots, sapstains, etc.)

Fungi reproduce by releasing airborne spores, which have different shapes and dimensions. Through spore liberation (the process of detachment of spore from the spore-bearing structure) and spore dispersal (the subsequent movement of the spore before settling on a material surface), spores travel through air, water and event on other insects from fungal infesting areas into homes and rest on surfaces and in building envelope. Concentrations of spores in outdoor and indoor air have been the target for much research (Ingold, 1971 and Darrell, 1974).

Spore diameters (Unit: micron):

• Alternaria, 8-75,
• Aspergillus 2-10,
• Cladosporium4-20,
• Epicoccum 20,
• Penicillium 3-5,
• Periconia 16-18,
• Stemphylium 23-75,

Spores present in the air settle on surfaces. When conditions are favorable, spores start the growth process. Spores go through four stage of development: maturation, dormancy, activation, and germination (Burnett, 1976). The combined process is usually referred to as germination, and will be discussed in more detail in the next section.

Once activated and germinated, the resulting germ tube is ready to grow into hyphae, then a cluster mycelium when conditions are favorable. In this (vegetative) growth stage, fungi produce microscopic, cylindrical filaments, the thread-like cellular strands called hyphae, into the food sources (material). These hyphae produce and excrete digestive enzymes in the food and take up nutrients in watery form (Figure 4), and transport them to the growing hyphal tips. The hyphae grow by extending itself on the tip or by branching out new threads at the tip and in the older parts. The total quantities of hyphae produced by a fungus are collectively termed as a mycelium. Figure 5 shows images of some mycelia.

The mycelium grows into the material (substrate), consumes its organic components in the process, wakens the structure of the material, and eventually destroys the structure and renders the material incapable to fulfil its function.

(Source: J. Rao, 1999) References for mold and fungi studies for a list of related reference.

• fungi overview,
• fungi and its place in nature,
• fungi: classificattion,
• fungi: life cycle of,
• fungi: health effect,
• molds as visible part of fungi,
• Encyclopeadia Britannica reference of fungi,
• Encyclopeadia Britannica definitions related to fungi,
• References for mold and fungi studies for a list of related reference.,
• Mycotoxins in water damaged buildings,
• Fungus, mold: web sites,
• Mycology and Building Mycology,

Essay: References for mold and fungi studies

Tibits:

Images for Life cycle of a basiomycete and

Life cycle of an ascomycete