Page 2 Plant-Bacteria Interactions Edited by Iqbal Ahmad, John ...

268j 14 Salt-Tolerant Rhizobacteria: Plant Growth Promoting Traits
Table 14.5 Production of B vitamins and amino acids by salt-tolerant bacterial strains.
Bacterial isolates B1 B3 B6 PP Biotin Norvaline Gistidine Leicin Valine Glutamine
P. alcaligenes PsA15 þ a
þ þ þ þ þ
P. denitrificans PsD6 þ þ þ þ
P. mendocina PsM13 þ þ þ
B. laevolacticus BcL28 þ þ þ
B. megaterium BcM48 þ þ þ þ þ
B. polymyxa BcP26 þ þ þ
M. phlei MbP18 þ þ þ þ þ þ þ
A. globiformis ArG1 þ þ þ þ
A. simplex ArS50 þ þ þ þ þ þ
A. tumescens ArT16 þ þ þ þ þ þ
a þ and indicate the presence or absence of activity by a particular microorganism.
proteins produced by microbes are regarded as important sources of catalysts for
plant growth in arid saline soils.
14.6
Plant Growth Stimulation in Arid Soils
The magnitude of plant response to microbial inoculation is greatly affected by
nutrient availability in soil [102]. In our previous studies, 233 bacterial strains were
isolated from weakly saline arid soils in Tashkent province and 480 strains from
strongly saline soils near the Aral Sea basin to evaluate their beneficial properties on
plants. About 30% of the strains were isolated from non inoculated plants, 15% from
weakly saline soils where they stimulated both shoot and root growth in plants and
24% were found to inhibit plant growth. From these isolates, about 21% of the
bacteria were responsible for causing a number of plant root diseases. Numbers of
growth stimulators were lower (9%) compared to inhibitors (21%) and diseasecausing
strains (16%) among the bacteria isolated from saline soils in Uzbekistan
(Table 14.6).
Table 14.6 Effects of rhizosphere bacterial strains on wheat plant growth in saline soils.
Effects
Weakly saline
soil (%)
Stimulators 15.2 9.3
Inhibitors 23.9 21.2
Disease-causing strains 21.0 16.2
Antagonist against F. culmorum 556 2.57 1.53
Strongly saline
soil (%)