Physiological and biochemical properties of the exudate associated with developing sclerotia of Sclerotinia sclerotiorum (Lib.) DeBary

Abstract

Physiological and biochemical properties of the liquid exuded from developing sclerotia of Sclerotinia sclerotiorum were studied. In aging cultures the weight of dry matter, total proteins, free ammonia, crude lipid, potassium, and magnesium decreased, whereas sodium and the pH of the liquid increased. In general, the free amino acids decreased. Specific activities of catalase, peroxidase, polyphenoloxidase, and β-glucosidase did not follow similar trends. Catalase and β-glucosidase activities were high during the pigmentation phase of sclerotia development. Trehalase activity was not detected. Disc-gel electrophoretic patterns for proteins, peroxidases, and polyphenoloxidases are shown. Alpha-ketoglutaric, glyoxylic, malic, and succinic acids were detected. An hypothesis to account for the presence of large drops of liquid on the surface of developing sclerotia is proposed.