Metabolic adaptation to prolonged anoxia in leaves of American cranberry (Vaccinium macrocarpon).

The indigenous North American Cranberry (Vaccinium macrocarpon), when cultivated in specially constructed cranberry bogs, is normally flooded in winter to prevent frost injury. This protection under ice can give rise to prolonged periods of anoxia, which depending on the state of the vines and environmental conditions, can cause severe oxygen-deprivation injury. An experimental study of the tolerance of cranberry vines to controlled total anoxia reveals that mature dark-green perennating leaves with high carbohydrate levels are able to survive prolonged periods of total oxygen-deprivation while younger newly formed leaves are readily damaged. During the anoxic treatment the mature leaves exhibit a marked downregulation of metabolism. Carbohydrate consumption and energy metabolism stabilize at low levels soon after the switch from aerobic to anaerobic pathways. Pathways such as TCA cycle or photosynthesis, which are non-operating during the anoxia treatment, are severely affected but still measurable after 28 days anoxia. In the post-anoxic period the perennating leaves rapidly re-establish their capacity for aerobic respiration and photosynthesis.