TRANSPORT PROCESSES AT THE PLANT-FUNGUS INTERFACE IN MYCORRHIZAL ASSOCIATIONS - PHYSIOLOGICAL-STUDIES

The roots of most plants form symbiotic associations with mycorrhizal fungi. The net flux of nutrients, particularly phosphorus (P), from th e soil into the plant is greater in mycorrhizal than in comparable non -mycorrhizal plants. However despite the widespread occurrence of myco rrhizal associations the processes controlling the transfer of solutes between the symbionts are poorly understood. To understand the mechan isms regulating the transfer of solutes information about conditions a t the interface between plant and fungus is needed. Measurements of ap oplastic and intracellular electrical potential difference in leek roo ts colonised by mycorrhizal fungi and estimates of cytosolic pH in fun gal hyphae are presented. These and the implications for plant/fungal mineral nutrition in vesicular-arbuscular mycorrhizas are discussed.