Heafb. Hamuda et al., THE INFLUENCE OF NITRAPYRIN AND SODIUM-AZIDE ON THE GROWTH AND RESPIRATION OF SOME RHIZOBIUM STRAINS, Microbiological research, 151(3), 1996, pp. 247-251
In vitro addition of different concentrations of nitrification inhibit
or nitrapyrin and respiratory inhibitor sodium azide to the growth med
ia of seven Rhizobium strains representing the four Rhizobium species
(R. leguminosarum, R. phaseoli, R. trifolii and R. loti) influenced th
e growth of these strains within 48 h at 28 degrees C incubation on a
rotary shaker. All doses of nitrapyrin inhibited growth. In contrast,
0.1 mg l(-1) enhanced the respiration rate of the strains using Warbur
g's respirometer. The doses 10 and 100 mg l(-1) were highly toxic and
depressed the respiration rates of Rhizobium within 180 minutes. Appli
cation of 10 mM NaN3 enhanced the growth and respiration rates of all
the strains. The growth of R. leguminosarum (Lobab Z and Bukkony 75/4
strains) was stimulated by 20 mM and also R. phaseoli (Bab 5/3 strain)
by 30 mM NaN3. The growth and respiration rates of the tested Rhizobi
um strains were significantly depressed by 50 mM NaN3, whereas the res
piration rates of the strains Lobab Z, Bukkony 75/4 and Bab 5/3 at 30
mM NaN3 were higher than the control. However, 50 mM NaN3 was signific
antly high and depressed the respiration rates of Rhizobium strains at
P = 0.05.