Osmotic Stress and the Hatching of Globodera Rostochiensis

When hatched juveniles are transferred from distilled water to 0.4 M sucrose or trehalose solutions their water content falls from 72% to 67%, the value observed for unhatched juveniles in eggs equilibrated with water. Juveniles move little after 6 hr immersion in 0.4 M or more concentrated sugar solutions, but dilution with water to give a sugar concentration 0.1 M restores many to active movement. Few juveniles emerge from cysts in solutions of potato-root diffusate or of an artificial hatching agent (0.4 mM picrolonic acid) which contain sucrose at concentrations 0.4 M. The evidence suggests that loss of solutes from the egg fluid permits hatching and supports the belief that changes in permeability of the egg shell precede other steps in the hatching process. Prolonged storage of second-stage juveniles is possible in 0.4 M solutions of sugars.