BIOCHEMICAL AND MORPHOLOGICAL MODIFICATIONS DURING THE GROWTH OF TUBER BORCHII MYCELIUM

This paper reports the first biochemical characterisation of Tuber bor chii mycelial strain ATCC 96540, grown in liquid media containing eith er glucose, fructose or sucrose. A new biochemical method, based on th e estimation of total protein content, was developed for determining t he amount of mycelium growth. This method is more sensitive than other methods, allowing growth to be monitored in the lag phase and when sm all amounts of mycelium are grown on a solid medium. Mycelium of T. bo rchii utilizes glucose and fructose as carbohydrate sources but grows poorly if at all on sucrose. In these experiments the functional state of the mycelium was evaluated by determining the activity of enzymes of the glycolytic and pentose phosphate pathways which are involved in producing energy and in supplying reducing power through the formatio n of reduced pyridine coenzymes. The biochemical data on mycelium grow th were supported by observations on ultrastructural morphology which revealed the different steps in hyphal depletion during ageing. In add ition, the monitoring of alanine content of the liquid media during my celial growth indicated that there was an increasing loss of alanine f rom their cytoplasm as hyphae aged. The development of this procedure makes it possible to identify the conditions under which T. borchii is able to synthesize a mycorrhiza with a compatible host.