Growth and respiration of psychrophilic species of the genusTyphula

摘要

Growth of three snow mold fungi,Typhula idahoensisRemsb.,T. incarnataLasch ex Fr., andT. trifoliiRostr., was studied in agar and liquid culture.T. idahoensiswas grown successfully in shake culture and its respiratory physiology investigated; some of the attendant problems are discussed.All three fungi were highly psychrophilic. The optimum temperatures for growth were 5ndash;10 deg;C, the maximum about 20 deg;C and the minimum around minus;5 deg;C. Sclerotia were produced at all temperatures which permitted growth, but most abundantly at temperatures above 10 deg;C.Cultures grown at 10 deg;C ceased to grow on transfer to temperatures above 20 deg;C but, within limits, growth resumed on return to 10 deg;C after a lag period approximately proportional to the degree and duration of the temperature elevation.Oxygen uptake byT. idahoensiswas optimal at 20 deg;C, about 15 deg;C higher than the optimum growth temperature.Respiratory quotients tended to be higher at 20 deg;C than at 5 deg;C and after starvation of the mycelium increased to a greater degree at 20 deg;C on addition of glucose or acetate. Starvation of the mycelium effectively reduced the level of endogenous reserves.The fungus was able to use, to differing degrees, a variety of hexose and pentose sugars as respiratory substrates. The percentage stimulation of the oxygen uptake by these sugars was greater at 20 deg;C than at 5 deg;C.