Fungal mycelia are iterative and modular structures with different branching strategies according to the nature of the substratum and abundance of nutrients. Two types of experiments were developed to mimic nutrient poor and nutrient rich substrata: fragments were excised from litter leaves corresponding to substrate discontinuity and were sealed with cover slips to allow the developing mycelia to bridge the formed gap. In an alternative experiment, drops of agar malt medium were placed on leaves and incubated for 44 hours. CCD camera captured images of growing mycelia were visualized in polarized light and camera lucida drawings (scanned subsequently) were submitted to image analysis. Fractal analysis was performed on both types of images using HARFA program. The calculated fractal exponent is a good descriptor of mycelia branching and growth. In nutrient poor environment, the fractal exponent describes foraging type of mycelia branching due to explorative growth strategy (between D= 1.14 and 1.32) while in nutrient rich environment it describes the exploitative growth strategy (between D=1.62 and D=1.89)

fungal mycelia strategies; fractals; foliar litter

Presentation: oral