Coiling is Not Essential to Anhydrobiosis by Aphelenchus avenae on Agar Amended with Sucrose

The roles of preconditioning and coiling upon entrance into anhydrobiosis by Aphelenchus avenae were tested via video-assisted analysis at 25(2) degrees C. Fourth-stage juveniles or young adults of A. avenae were individually placed on 5% agar containing 0.8 M sucrose. Nematodes became quiescent within 3 hr, then gradually resumed a low level of activity and assumed a coiled posture. High desiccation survival rate was recorded when nematodes were incubated on agar for more than 6 hr; the survival rates were 0%, 3%, 73%, and 92% for 0, 2, 6, and 12 hr on agar, respectively. All nematodes placed on agar for 24 hr or more revived after rehydration following desiccation. Once nematodes were on agar for a sufficient time, no difference in desiccation survival was observed between nematodes taking a coiled posture and those uncoiled artificially. Based on these results, exposure to osmotic stress for 6 hr can prepare A. aveae physiologically for anhydrobiosis, but coiling does not appear to be a physiological requirement for desiccation in survival.