GROWTH-KINETICS OF MYCELIAL COLONIES AND AGGREGATES OF ASCOMYCETES

Many aspects of hyphal extension and branching in fungi are well understood at the cellular level and may be linked to the growth kinetics of individual hyphae and branching mycelia on solid media and in liquid culture. Thus, growth of a typical colony on solid medium may be described and quantified, using concepts such as the peripheral growth zone and hyphal growth unit. These concepts also increase our understanding of growth of dispersed mycelia in liquid culture. 'Atypical' growth, e.g. sector formation, rhythmic growth, pellet formation are less well understood, but provide a link between vegetative mycelial growth and aggregation of hyphae to form more complex differentiation structures. Aggregate formation is frequently associated with alterations in the balance between hyphal extension rate and branch production but temporal and spatial control of these processes is not well understood. This 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.