SOIL AERATION, NITRATE REDUCTION AND FLOODING TOLERANCE IN HIGHER PLANTS

Abstract

SUMMARY Flood‐tolerant species from natural habitats differ from flood‐intolerant species by being able to make more effective use of nitrate as an alternative electron acceptor to oxygen during periods of partial anaerobiosis. When flooded, tolerant species show marked increases in nitrate‐reductase activity in roots and leaves. A greater ability to synthesize amino‐acids under anoxia was also found in the tolerant species than in the intolerant. It is suggested that these properties enable the flood‐tolerant species to facilitate the re‐oxidation of NADH 2 under conditions of anoxia and that this is associated with the greater ability of the species to withstand a reduction in the partial pressure of oxygen.