Decomposition of lignocellulosic resources in boreal, temperate and tropical climates is determined by the types of decay fungi present, and the prevailing environmental conditions (Cartwright and Findlay, 1958; Boddy and Rayner, 1988). Basidiomycota are frequently the dominant decomposer organisms and are thus critical in nutrient cycling in ecosystems. These fungi can also cause significant economic damage as pathogens and decomposers of buildings, other human artefacts and food stuff, by virtue of their ability to utilise cellulose, hemicellulose and lignin. Their mycelial habit and the production of aggregated mycelial structures—cords and rhizomorphs, allow them to forage for and colonise heterogeneously distributed bulky resources (Chapter 1). Saprotrophic Basidiomycota are exposed during these processes to a range of fluctuating environmental conditions, especially of water availability, temperature, pH and gaseous regime. These factors individually, and interacting, have an impact on the ability to grow, colonise different lignocellulosic matrices, produce the necessary enzymes for decomposition and to be competitive. This chapter considers the impact of abiotic factors, especially temperature and water availability, on the activity of saprotrophic Basidiomycota, their mechanisms of tolerance and ability to produce the necessary enzymes which enable them to be such important components of decomposition processes and nutrient recycling. Examples are chosen from temperate and tropical species in natural ecosystems, as well as cultivated species such as A. bisporus and Pleurotus spp.

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