Kinetics of growth

When fungi are filamentous their growth rate cannot be established by cell counting using a hemocytometer or by turbidometric measurements. However, by measuring mass (M) changes with time (t) under excess nutrient conditions the specific growth rate (m) for the culture can be calculated using the formula:

                                             Figure . Colonial  growth patterns of filamentous fungi.

                                                                dM/dt = mM

the Fungal growth in a provided medium follows the growth phases of lag, acceleration, exponential, linear, retardation, stationary and decline.
Exponential growth occurs only for a brief period as hyphae branches are initiated and then the new hypha extends at a linear rate into uncolonized regions of substrate. The Only hyphal tips contribute to extension for growth. However, older hyphae can grow aerially or differentiate to produce sporing structures.