Abstract
Azospirillum brasilense, a nitrogen-fixing bacterium found in the rhizosphere of various grass species, was investigated to establish the effect on plant growth of growth substances produced by the bacteria. Thin-layer chromatography, high-pressure liquid chromatography, and bioassay were used to separate and identify plant growth substances produced by the bacteria in liquid culture. Indole acetic acid and indole lactic acid were produced by A. brasilense from tryptophan. Indole acetic acid production increased with increasing tryptophan concentration from 1 to 100 mug/ml. Indole acetic acid concentration also increased with the age of the culture until bacteria reached the stationary phase. Shaking favored the production of indole acetic acid, especially in a medium containing nitrogen. A small but biologically significant amount of gibberellin was detected in the culture medium. Also at least three cytokinin-like substances, equivalent to about 0.001 mug of kinetin per ml, were present. The morphology of pearl millet roots changed when plants in solution culture were inoculated. The number of lateral roots was increased, and all lateral roots were densely covered with root hairs. Experiments with pure plant hormones showed that gibberellin causes increased production of lateral roots. Cytokinin stimulated root hair formation, but reduced lateral root production and elongation of the main root. Combinations of indole acetic acid, gibberellin, and kinetin produced changes in root morphology of pearl millet similar to those produced by inoculation with A. brasilense.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
Azospirillum brasilense produced indole acetic acid and indole lactic acid from tryptophan in liquid culture.
- Taxon
- A. brasilense
Azospirillum brasilensee1 - Compound
- tryptophane1
- Outcome
- Indole acetic acid and indole lactic acide1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum brasilense, a nitrogen-fixing bacterium”
e1“Indole acetic acid and indole lactic acid were produced by A. brasilense from tryptophan”
Claim · model-written summary
Indole acetic acid production by A. brasilense increased with increasing tryptophan concentration from 1 to 100 mug/ml.
- Taxon
- Azospirillum brasilenseAzospirillum brasilensee0
- Compound
- tryptophane1
- Outcome
- Indole acetic acid productione1
- Direction
- increasede1
- Qualifier
- from 1 to 100 mug/mle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum brasilense, a nitrogen-fixing bacterium”
e1“Indole acetic acid production increased with increasing tryptophan concentration from 1 to 100 mug/ml”
Claim · model-written summary
Indole acetic acid concentration in A. brasilense cultures increased with culture age until the bacteria reached the stationary phase.
- Taxon
- Azospirillum brasilenseAzospirillum brasilensee0
- Treatment
- age of the culturee1
- Outcome
- Indole acetic acid concentratione1
- Direction
- increasede1
- Qualifier
- until bacteria reached the stationary phasee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum brasilense, a nitrogen-fixing bacterium”
e1“Indole acetic acid concentration also increased with the age of the culture until bacteria reached the stationary phase”
Claim · model-written summary
Shaking favored indole acetic acid production by A. brasilense, especially in a nitrogen-containing medium.
- Taxon
- Azospirillum brasilenseAzospirillum brasilensee0
- Treatment
- Shakinge1
- Outcome
- production of indole acetic acide1
- Direction
- favorede1
- Qualifier
- especially in a medium containing nitrogene1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum brasilense, a nitrogen-fixing bacterium”
e1“Shaking favored the production of indole acetic acid, especially in a medium containing nitrogen”
Claim · model-written summary
A small but biologically significant amount of gibberellin was detected in the A. brasilense culture medium.
- Taxon
- Azospirillum brasilenseAzospirillum brasilensee0
- Outcome
- amount of gibberelline1
- Qualifier
- small but biologically significante1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum brasilense, a nitrogen-fixing bacterium”
e1“A small but biologically significant amount of gibberellin was detected in the culture medium”
Claim · model-written summary
At least three cytokinin-like substances, equivalent to about 0.001 mug of kinetin per ml, were present in the A. brasilense culture.
- Taxon
- Azospirillum brasilenseAzospirillum brasilensee0
- Outcome
- cytokinin-like substancese1
- Value
- 0.001 mug of kinetin per mle1
- Qualifier
- at least threee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azospirillum brasilense, a nitrogen-fixing bacterium”
e1“at least three cytokinin-like substances, equivalent to about 0.001 mug of kinetin per ml, were present”
Claim · model-written summary
Inoculation with A. brasilense increased the number of lateral roots of pearl millet plants in solution culture.
- Taxon
- pearl millet
Cenchrus americanuse0 - Organ / stage
- rootse0
- Treatment
- inoculation with A. brasilensee2
- Interactor
- A. brasilenseAzospirillum brasilensee2symbiont
- Outcome
- number of lateral rootse1
- Direction
- increasede1
- Setting
- solution culturee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The morphology of pearl millet roots changed when plants in solution culture were inoculated”
e1“The number of lateral roots was increased”
e2“inoculation with A. brasilense”
Claim · model-written summary
In pearl millet inoculated with A. brasilense, all lateral roots were densely covered with root hairs.
- Taxon
- pearl milletCenchrus americanuse0
- Organ / stage
- rootse0
- Treatment
- inoculation with A. brasilensee2
- Interactor
- A. brasilenseAzospirillum brasilensee2symbiont
- Outcome
- lateral roots were densely covered with root hairse1
- Setting
- solution culturee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The morphology of pearl millet roots changed when plants in solution culture were inoculated”
e1“all lateral roots were densely covered with root hairs”
e2“inoculation with A. brasilense”
Claim · model-written summary
Gibberellin increased lateral root production in pearl millet in experiments with pure plant hormones.
- Taxon
- pearl milletCenchrus americanuse1
- Treatment
- gibberelline0
- Outcome
- production of lateral rootse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Experiments with pure plant hormones showed that gibberellin causes increased production of lateral roots”
e1“The morphology of pearl millet roots”
Claim · model-written summary
Cytokinin stimulated root hair formation in pearl millet.
- Taxon
- pearl milletCenchrus americanuse1
- Treatment
- Cytokinine0
- Outcome
- root hair formatione0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cytokinin stimulated root hair formation”
e1“The morphology of pearl millet roots”
Claim · model-written summary
Cytokinin reduced lateral root production and elongation of the main root in pearl millet.
- Taxon
- pearl milletCenchrus americanuse1
- Treatment
- Cytokinine0
- Outcome
- lateral root production and elongation of the main roote0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cytokinin stimulated root hair formation, but reduced lateral root production and elongation of the main root”
e1“The morphology of pearl millet roots”
Claim · model-written summary
Combinations of indole acetic acid, gibberellin and kinetin produced changes in pearl millet root morphology similar to those produced by inoculation with A. brasilense.
- Taxon
- pearl milletCenchrus americanuse0
- Treatment
- Combinations of indole acetic acid, gibberellin, and kinetine0
- Interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- changes in root morphologye0
- Comparator
- inoculation with A. brasilensee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Combinations of indole acetic acid, gibberellin, and kinetin produced changes in root morphology of pearl millet similar to those produced by inoculation with A. brasilense”
The same questions in other papers
Azospirillum brasilense · growth · Cenchrus americanus (pearl millet)Results agree
1 paper in the same direction as this paper
- positive
class · growth · Cenchrus americanus (pearl millet)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
inoculation · growth · Cenchrus americanus (pearl millet)Positive and negative results
20 papers in the same direction as this paper · 3 in the opposite direction
- positive
- negative
- no effect
20 papers more in this group
See all 24 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.