GROWTH-KINETICS OF MYCELIAL COLONIES AND AGGREGATES OF ASCOMYCETES

Many aspects of hyphal extension and branching in fungi are well under stood at the cellular level and may be linked to the growth kinetics o f individual hyphae and branching mycelia on solid media and in liquid culture. Thus, growth of a typical colony on solid medium may be desc ribed and quantified, using concepts such as the peripheral growth zon e and hyphal growth unit. These concepts also increase our understandi ng of growth of dispersed mycelia in liquid culture. 'Atypical' growth , e.g. sector formation, rhythmic growth, pellet formation are less we ll understood, but provide a link between vegetative mycelial growth a nd aggregation of hyphae to form more complex differentiation structur es. Aggregate formation is frequently associated with alterations in t he balance between hyphal extension rate and branch production but tem poral and spatial control of these processes is not well understood. T his review emphasizes the need for a quantitative approach to studies on aggregate formation, and discusses the application of mathematical models describing differentiation and pattern formation.