TY - JOUR

T1 - Population dynamics of the fast-growing sub-populations of Pseudomonas and total bacteria, and their protozoan grazers, revealed by fenpropimorph treatment

AU - Thirup, L

AU - Ekelund, Flemming

AU - Johnsen, Kaare Eske

AU - Jacobsen, Carsten Suhr

N1 - Author Keywords: Predation; Fenpropimorph; Pseudomonas; Protozoa; Bacteria; Soil; Micro CFU

PY - 2000

Y1 - 2000

N2 - The population dynamics of indigenous soil bacteria and protozoa on decaying barley roots were followed by using litter bags buried in laboratory-incubated soil. The soil was either non-treated or treated with the fungicide fenpropimorph (in the formulation Corbel) at concentrations corresponding to the recommended and at 10 times field dose (1.3 and 13 mg kg-1 dry wt.). Number of total bacteria and number of Pseudomonas were detected, using both traditional plating and short-time incubations of ‘early' colonies, to determine the fast-responding subpopulation of the culturable bacteria. The number of protozoa corresponding to the two subpopulations was followed. The results strongly indicate a predatory association between the protozoa and bacteria. This was shown by a tight temporal association, and by a stimulation of bacteria following predatory release when protozoa were inhibited by fenpropimorph. Thus, fenpropimorph disturbed population dynamics in concentrations, which can be reached in surface soils after distribution in the field.

AB - The population dynamics of indigenous soil bacteria and protozoa on decaying barley roots were followed by using litter bags buried in laboratory-incubated soil. The soil was either non-treated or treated with the fungicide fenpropimorph (in the formulation Corbel) at concentrations corresponding to the recommended and at 10 times field dose (1.3 and 13 mg kg-1 dry wt.). Number of total bacteria and number of Pseudomonas were detected, using both traditional plating and short-time incubations of ‘early' colonies, to determine the fast-responding subpopulation of the culturable bacteria. The number of protozoa corresponding to the two subpopulations was followed. The results strongly indicate a predatory association between the protozoa and bacteria. This was shown by a tight temporal association, and by a stimulation of bacteria following predatory release when protozoa were inhibited by fenpropimorph. Thus, fenpropimorph disturbed population dynamics in concentrations, which can be reached in surface soils after distribution in the field.

U2 - 10.1016/S0038-0717(00)00075-4

DO - 10.1016/S0038-0717(00)00075-4

M3 - Journal article

VL - 32

SP - 1615

EP - 1623

JO - Soil Biology & Biochemistry

JF - Soil Biology & Biochemistry

SN - 0038-0717

IS - 11-12

ER -