ECOPHYSIOLOGY OF PLANTS IN WATERLOGGED AND FLOODED ENVIRONMENTS

The adaptation of higher plants to waterlogged and flooded environments is reviewed. The primary effect in the sequence of waterlogging-induced processes is a reduction of the oxygen concentration of the soil. The longer the period of waterlogging lasts, the more the speciation of nitrogen, manganese, iron, sulphur and carbon changes from the oxidized to the reduced state, often counteracted by a well-functioning aerenchyma. The change in the speciation of soil nitrogen has no effecct on plant resistant to waterlogging, whereas reduction of sulphur demands specific adaptations. Secondary metabolic changes as reactions to waterlogging will involve glycolysis, but depend on the extent of anoxia in the soil and thus the root. Flooding will enhance the sequence of waterlogging-induced processes. As soon as the green plant parts are flooded and excluded (partially) from the ambient air, a reduction in photosynthesis will take place and severely affect the energy budget. In addition to ecophysiological adaptation, waterlogging-resistant species may play a role in the survival of less resistant species in the same plant community. © 1990.