DETAILED VISUALIZATION OF HYPHAL DISTRIBUTION IN FUNGAL MYCELIA GROWING IN HETEROGENEOUS NUTRITIONAL ENVIRONMENTS

A technique is described which enables high resolution images of the d istribution of individual hyphae within fungal mycelia to be obtained, when the fungi are growing in nutritionally heterogeneous environment s. The basis of the technique is to project colonies grown on the surf ace of cellulose membranes onto high contrast film using a photographi c enlarger. Heterogeneity of nutrient resources is controlled by overl aying the membrane onto the surface of a box designed to hold disposab le pipette tips, where the holes designed to hold the tips have been f illed with gels of contrasting nutrient status. The effect of regular and irregular patterns of relatively high and low nutrient status gels upon development of single mycelia of Trichoderma viride and Rhizocto nia solani is shown. The technique can readily image mycelia up to 30 cm(2) whilst still permitting resolution of individual hyphae where nu trient supply is sufficiently low to result in low hyphal densities.