Abstract
Process of glucose assimilation by soil microbes and stressing effect of sodium chloride on the assimilation were quantitatively analyzed by a calorimetric method. One-tenth mmol glucose was added to 10 g of paddy, upland, and orchard soils in the absence and presence of various concentrations of sodium chloride, and the assimilation heat was recorded at 25 ºC. The heat-evolution curves were successfully analyzed on the basis of the Gompertz model. The effects of sodium chloride on the assimilation were evaluated by measuring the change in Gompertz parameters. Among the parameters, the time T1/2 at which half of the total heat evolution completed, and the time M at which the heat-evolution rate reaches to the maximum were suitable for accurate evaluation of the inhibitory effects of sodium chloride. The 50 % inhibitory concentration Ki of sodium chloride for the paddy, upland, and orchard soils were evaluated to be 3.9, 3.5, and 6.7 %, respectively, and the minimum inhibitory concentration MIC were 6.9, 6.7, and 12 %, respectively. This novel method can be a standard one for evaluating soil pollution and remediation using assimilation activity of microorganisms including nonculturable ones as a probe.
https://ror.org/01529vy56 
