Meeting Abstract
P2.193 Monday, Jan. 5 Desiccation tolerance and drought acclimation in the Antarctic collembolan Cryptopygus antarcticus ELNITSKY, M.A.*; BENOIT, J.B.; DENLINGER, D.L.; LEE, R.E.; Mercyhurst College; Ohio State University; Ohio State University; Miami University melnitsky@mercyhurst.edu
Within the maritime Antarctic, arthropods may be challenged by drought stress during both the austral summer, due to increased temperature, wind, and periods of reduced precipitation, and winter, as a result of the lower vapor pressure of the surrounding icy environment. The purpose of the present study was to assess the desiccation tolerance of the Antarctic springtail, Cryptopygus antarcticus, under conditions characteristic of the Antarctic Peninsula, and examine the physiological effects of mild drought acclimation on the subsequent desiccation tolerance. Under ecologically-relevant desiccating conditions, springtails lost water at all relative humidities below saturation (100% relative humidity – RH). However, slow dehydration at high relative humidity dramatically increased the desiccation tolerance of C. antarcticus. A mild drought acclimation at 98.2% RH further increased the springtails desiccation tolerance. Drought acclimation was accompanied by the accumulation of several sugars and polyols that would function to stabilize membranes and proteins during dehydration. The springtails were also susceptible to desiccation at subzero temperatures in equilibrium with the vapor pressure of ice; springtails lost ~40% of their body water over 28 d when cooled to -3.0oC. The concentration of solutes in the remaining body fluids as a result of dehydration, together with the synthesis of several osmolytes, depressed the melting point to approx. -2.2oC, and may therefore allow C. antarcticus to survive much of the Antarctic winter in a cryoprotectively dehydrated state.
