Spore Germination and Carbon Metabolism in Fusarium solani. III. Carbohydrate Respiration in Relation to Germination

Publisher Website
Google Scholar
Abstract
Sugars which support germination are oxidized more rapidly and with less oxidative assimilation than those which do not; germination is accompanied by an increase in the rate of oxidation of only those sugars which can be utilized for germination. The rate of glucose oxidation is inversely proportional to spore density, but the rate of endogenous respiration and the extent of utilization of glucose are invariant with density; the latter observation is interpreted as evidence that glucose does not suppress or accelerate endogenous respiration. Oxygen availability is not the factor responsible for the density effect. Assimilated glucose is incorporated primarily into a fraction extractible with 80% ethanol, and the major identifiable compound formed is mannitol. Oxidatively assimilated glucose is not appreciably incorporated into cell lipids. Both the provision of ammonium N and germination result in characteristic changes in the conversion of specific carbon atoms of glucose to carbon dioxide; it is suggested that these changes reflect the acceleration of reactions which lead by way of pyruvate to amino-acid synthesis. Ungerminated spores produce neither acid nor carbon dioxide from glucose anaerobically; a weak capacity to ferment glucose is induced by germination or by incubation for a short period in contact with compounds required for germination.