Comparative Studies on the Primary and Secondary Zoöspores of the Saprolegniaceae. I. Influence of Temperature

SUMMARY

The activity of the primary and secondary zoöspores in four genera of the Saprolegniaceae was studied and compared at temperatures from 5° to 35° C. Under carefully controlled conditions, primary zoöspores, for example, swarmed for a shorter period, carried on normal activity over a narrower temperature range, moved at a slower rate, and had a higher temperature coefficient than the secondary. Since the two types have different “temperature characteristics,” their activities are probably controlled by different catalysts.