Biomedical Engineering Reference
In-Depth Information
Simultaneously with ammonification the process of nitrification takes place in soil. But,
in studied typical serozyom the number of nitrifying bacteria is low. Maximum of their
development was observed in phase of maturation (1.2 x 10
5
CFU/g soil). Quantity of
denitrifying bacteria in test soil depending on phase of cotton development varied from 3.5 x
10
5
to 7 x 10
5
CFU/g of soil. Azotobacter content in serozyom soil did not change much and
was within 3-10 x 10
3
CFU/g soil.
Figure 3. Influence of Verbactin on microorganisms participating in cellulose degradation.
Serozyom soil in autumn is puddle, irrigation and dressing are stopped, soil temperature
is lowered, highly developed cotton root system starts dying off, microbial activity runs
smoothly. Verbactin expressed prolonged action on bacteria, actynomycetes and fungi, which
activated mineralization of plant debris, humic compounds. Actynomycetes and spore
bacteria are capable to degrade complex plant materials due to presence of enzymes, and
development of cellulose degrading aerobic bacteria and fungi is linked with microbiological
schedule and direction of microbiological processes. Quantitative content of actynomycetes -
850, spore bacteria - 250, fungi - 30 thousands CFU/g of soil reveal high mineralization of
plant organic matter.
Specific interest was paid to study the Verbactin influence on content of microorganisms-
antagonists in cotton rhizosphere. It was established that preparation stimulates growth and
development of bacteria, streptomycetes and fungi that inhibit growth and development of
Verticillium wilt agent. These cultures induced cotton plants resistance to fungal infection as
well. The highest quantity of antagonists was observed in phase of flowering (207 bacterial
strains from genera
Bacillus, Pseudomonas, Arthrobacter
, 96 actynomycetes strains from
genera
Streptomyces
,
Streptoverticillium
, 70 fungal strains from genera
Aspergillus
,
Penicillium, Fusarium, Stachybotrys, Acremonium, Trichoderma, Gliocladium
)
.
Considerably
less number of antagonists was isolated in phase of maturation (91 bacterial strain from
genera
Bacillus, Arthrobacter
, 52 actynomycetes from genera
Streptomyces
,
Streptoverticillium
, 40 fungal strains from genera
Aspergillus
,
Stachybotrys, Acremonium,
Aspergillus, Penicillium
)
.
The most active antagonists expressing antibiotic activity towards
V. dahliae
(zone of pathogen growth suppression - 20-41 mm) were selected to determine
possibility of their use in biocontrol of cotton. It was established that in control plots an
increase in number of microorganisms takes place on account of phytopathogens:
Verticillium
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