The effects of waterlogging on root growth and on symbiotic nitrogen fixation by legumes [a review]
1987
Smith, K.A.
Chemical processes that occur in waterlogged soil, the effects of waterlogging on root growth of legumes and other agricultural crops, and its effects on symbiotic fixation of nitrogen are reviewed and mechanisms thought to be responsible for sensitivity to, or tolerance of, anaerobic conditions in the soil are discussed. Crop species vary widely in their response to flooded conditions, and legumes, with a few exceptions, are generally regarded as among the most sensitive species. Tolerance of waterlogging appears to be associated with the capacity to develop oxygen-conducting aerenchyma within roots, and with a rate of endogenous ethylene production too low to inhibit root extension. Similarly, the capacity of leguminous nodules to survive and fix nitrogen in waterlogged soil is associated with the ability to develop a loose structure that facilitates gaseous exchange. Nitrogenase activity is especially sensitive to ethylene, and the rate of endogenous ethylene production under oxygen-deficient conditions may be an important factor in determining the sensitivity of legumes to waterlogging
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