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This article in SSSAJ

  1. Vol. 45 No. 3, p. 657-660
    Received: May 23, 1980
    Accepted: Jan 5, 1981

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ATP Concentration and Soil Respiration at Reduced Water Potentials in Arid Soils1

  1. W. G. Knight and
  2. J. Skujins2



Adenosine triphosphate (ATP) concentrations and soil respiration rates of two arid and one subalpine forest soil were evaluated as a function of water potential (ψw) in the range −2 to −100 bars. Water potential was determined by thermocouple psychrometry, CO2 release from soil by titrimetry; ATP was extracted from soil with cold sulfuric acid and assayed by luciferin-luciferase methology. ATP concentrations increased in the ψw range −2 to −20 bars in the arid soils and was negatively correlated (r2 = 0.92) with exponential decreases in respiration rates for the same ψw range. In the subalpine forest soil, the highest ATP concentration was at the highest measured water potential (−2 bars) and decreased with decreasing respiration rates (r2 = 0.93) and decreasing ψw values. It was concluded that the soil microflora may exhibit diverse physiological responses to water and, consequently, to available carbon-source induced stresses in soils from environmentally different areas.

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