Table 1 Effect of heat treatment on population densities of culturable bacteria and fungi in Allium plant-cultivated soils (cfu gram−1 dry soil).

From: Microbial basis of Fusarium wilt suppression by Allium cultivation

Rhizosphere soil

Microorganism

Heat treatment

No treatment

40 °C

60 °C

80 °C

121 °C

Welsh onion

Bacteria

   Gram-negative

0.7–1.3 × 108

0.6–1.1 × 108

<2.8 × 106

ND

ND

   Gram-positive

0.7–1.0 × 108

5.0–9.7 × 107

2.0–3.9 × 107

1.9–3.5 × 107

ND

Fungi

0.8–3.1 × 106

0.5–2.4 × 106

0.3–1.8 × 104

<1.5 × 102

ND

Onion

Bacteria

   Gram-negative

3.4–6.0 × 107

2.6–4.7 × 107

<1.9 × 106

ND

ND

   Gram-positive

4.0–6.7 × 107

2.1–3.0 × 107

2.0–3.0 × 107

2.3–2.7 × 107

ND

Fungi

2.4–2.7 × 105

1.5–1.8 × 105

2.3–3.7 × 103

<2.3 × 102

ND

  1. The culturable bacterial densities were estimated using 1/10 strength tryptic soy agar, and Gram reaction was determined using the KOH method. The culturable fungal densities were estimated using rose bengal-streptomycin agar. The experiment was repeated three times. ND: not detected.
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