Table 3.

MPN counts of bacteria in anoxic soil of flooded rice paddy soil microcosmsa

SubstrateTreatmentCell count (per g of dry soil)95% Confidence intervalProportion of sporesb
LactateNone5.0 × 106 9.8 × 105–2.1 × 107 2.2
Pasteurized1.1 × 105 2.1 × 104–4.0 × 105
EthanolNone3.4 × 107 1.1 × 107–8.2 × 107 0.03
Pasteurized1.1 × 104 2.1 × 103–4.0 × 104
3,4,5-TMBc None2.8 × 104 6.4 × 103–8.5 × 104 0.29
Pasteurized8.1 × 101 1.6 × 101–3.4 × 102
BetaineNone2.8 × 105 6.4 × 104–8.5 × 105 0.64
Pasteurized1.8 × 103 3.4 × 102–6.4 × 103
  • a Soil samples were first diluted as normal (see the text), and then the same sample was heated at 80°C for 15 min and used to carry out a second (pasteurized) dilution.

  • b The ratio of cells and spores culturable after pasteurization to those culturable prior to pasteurization, expressed as a percentage.

  • c 3,4,5-TMB, 3,4,5-trimethoxybenzoate.