AUTOMATED IMAGE-ANALYSIS METHOD TO DETERMINE FUNGAL BIOMASS IN SOILS AND ON SOLID MATRICES

A procedure has been developed for determining fungal biomass in soil and on inert surfaces by fluorescent staining and fully-automated image analysis. Soil samples were homogenised, filtered and stained with Calcofluor M2R (for total hyphal biomass measurements) or fluorescein diacetate (for viable biomass measurements). Fungi on inert surfaces were stained with Calcofluor M2R. Samples were examined by epifluorescence microscopy and images analysed using a Teragon-Contextvision GOP-302 system. Hyphal length and biovolume were calculated in a totally automated process and novel software routines were developed to differentiate fungal hyphae from other stained material. The principles of the software operations should be applicable to many other image analysis systems. Testing of the system against manual microscopic determination of length and known dry weights of mycelium demonstrated excellent correlation between the automated image analysis and other techniques. The method is rapid, accurate and minimises operator fatigue. Being wholly deterministic, the results obtained do not depend on the judgement of the operator. Application of the technique is illustrated with reference to experiments studying the growth of fungi inoculated into soils and the fungal colonisation of plastics.