The influence of flooding pretreatment on metabolic changes in winter cereal seedlings during ice encasement

Abstract

The survival of winter wheats during ice encasement is increased by pre-exposure to low temperature flooding. The response is duplicated by nitrogen exposure, indicating an anaerobic hardening process. During ice encasement, higher levels of ethanol accumulate in previously flooded plants than in nonflooded plants. Alcohol dehydrogenase activity is threefold higher at the end of a 2 week low temperature flooding period than in aerobically grown plants. The activity is lower after 3 days in ice. The decrease is similar in previously flooded and nonflooded plants, but is larger in Dover barley which is more susceptible to ice encasement stress than the wheats. Malate declines during flooding and is higher during ice encasement in nonflooded than in flooded plants. Previously flooded plants enter the more severe anaerobic stress of ice encasement with an accelerated glycolytic rate, and thus a higher survival potential.