Date of Award
Master of Science
Pure cultures of Saprolegnia parasitica Coker were grown under varied conditions of temperature, pH, and light conditions. In liquid medium colonies were spherical with a zonal effect in the distribution of zoo sporangia. Near the limiting extremes of pH and temperature, beaded hyphal tips were found in place of normal sporangia. Teorell Universal buffer in the sporulation water inhibited production of sporangia . The pH minimum was 4.0 - 4.1, optimum 6.3 - 7 .4, ·and maximum 8.0 - 8.3. The maximum number of sporangia was produced at 15 C. Between 3.4 and 5 C, a delay in sporulation was noted and at 0 - 1 C, no sporangia were formed. At 30 C and above; only abnormal sporangia formed.
Cultures grown in continuous artificial light produced double the number of sporangia compared with colonies grown in complete darkness. The average diameters of the colonies grown in complete darkness were 25 % less than average diameters of colonies grown in complete light. When cultures were grown in alternating light and darkness, those that received the greatest total illumination produced the greatest numbers of sporangia.
Lee, Philip C., "Some effects of pH, temperature and light on the production of Zoosporagia in Saprolegnia parasitica Coker" (1962). Master's Theses. 187.