Mechanisms of Plant Resistance to Waterlogging

A prolonged period of rainfall or over-irrigation combined with poor internal soil drainage often causes soil waterlogging. Waterlogging is a world-wide occurring event that has a major impact on both the natural vegetation and agricultural crops. Metabolic responses to hypoxia and anoxia have been studied extensively in many plant species, but a common metabolic mechanism conferring tolerance to these conditions has not been identified. Lactate dehydrogenase (LDH) is also induced anaerobically in roots and seeds of several species. The hypothesis of a fermentation pathway leading to accumulation of ethanol and consequently for flooding injury, however, has been questioned. The anatomical and morphological adaptations to waterlogging may be important long-term adaptations that contribute to waterlogging tolerance. The presence of aerenchyma in roots is clearly conducive to the survival of the plants under waterlogged conditions and has been considered as an adaptive response.