MODEL RELEASED. Plant-fungi research. Researcher using a microscope to examine a petri dish culture of a plant and the fungi associated with its roots. This research involves arbuscular mycorrhizal (AM) fungi, an an example of mycorrhizal symbiosis. These fungi are mutualistic symbionts living in the roots of many land plant species. Extensive underground fungal networks connect the roots of different plants and are essential for the uptake of soil nutrients and their transfer to the host plants. Photographed at the University of Pisa, Italy.