Abstract
The effects of plant growth promoting bacteria (PGPB) on the initial growth and leaf gas exchange parameters of maize plants ('Zea mays' L.), and bacterial population of the root and non-rhizosphere soil were investigated under different soil acidity levels. Maize plants were grown in 13-dm3 pots filled with clayey Rhodic Hapludox in a greenhouse. Treatments were arranged in a randomized block design in a 3 x 4 factorial: three soil acidity levels [pH in 0.01 mol L-1 CaCl2 solution of 4.5; 5.0 and 5.5] and four seed inoculation treatments [control (non-inoculated); inoculation with 'Azospirillum brasilense' strain AbV5; inoculation with 'Herbaspirillum seropedicae' strain SMR1; and inoculation with two bacteria strains ('A. brasiliense + H. seropedicae')]. Seeds inoculation with two PGPB strains (AbV5 and SMR1) improved the leaf area (14%), stem diameter (7%), relative chlorophyll content (14%), but had no effect on dry matter yield of maize plants, even with the changes of soil acidity levels. At 15 days after sowing, the inoculation of 'A. brasilense' resulted in increased of diazotrophic bacteria density in the soil (15%). At 41 days after sowing, the inoculation of PGPB strains (AbV5 and SMR1) resulted in increased of diazotrophic bacteria density in the maize roots (13%). Seed inoculation with 'H. seropedicae' enhances the nitrogen concentration in the leaf tissue of maize (12%) under soil acidity conditions and without the nitrogen supply, indicating increase in the biological nitrogen fixation. Inoculation of PGPB in acidic sandy soil (4.5 to 5.0 pH) resulted in higher phosphorus concentration in the leaf tissue of maize, indicating increase of phosphorus solubilization promoted by the diazotrophic bacteria. Leaf CO2 assimilation rate was not affected by the maize seed inoculation with PGPB. Soil acidity resulted in the reduction of stomatal conductance (-25%), leaf CO2 assimilation rate (-14%), leaf transpiration rate (-21%) and water use efficiency (-6%) of maize plants. The NFb Lactate (selective for 'A. brasilense') and NFb Malate (selective for 'H. seropedicae') culture media were not effective in differentiating of the two diazotrophic species studied and 'Herbaspirillum seropedicae', for both the root and soil samples.
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Claims 14
Claim · model-written summary
Dual PGPB inoculation improved maize leaf area by 14%.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seeds inoculation with two PGPB strains (AbV5 and SMR1) improved the leaf area (14%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
Dual PGPB inoculation improved stem diameter by 7%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seeds inoculation with two PGPB strains (AbV5 and SMR1) improved the leaf area (14%), stem diameter (7%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
Dual PGPB inoculation improved relative chlorophyll content by 14%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seeds inoculation with two PGPB strains (AbV5 and SMR1) improved the leaf area (14%), stem diameter (7%), relative chlorophyll content (14%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
Dual PGPB inoculation had no effect on maize dry matter yield.
- Treatment
- Seeds inoculation with two PGPB strains (AbV5 and SMR1)e0
- Interactor
- PGPBe0symbiont
- Outcome
- dry matter yielde0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seeds inoculation with two PGPB strains (AbV5 and SMR1) improved the leaf area (14%), stem diameter (7%), relative chlorophyll content (14%), but had no effect on dry matter yield of maize plants”
Claim · model-written summary
A. brasilense inoculation increased soil diazotrophic bacterial density at day 15 by 15%.
- Interactor
- A. brasilense
Azospirillum brasilensee0e1symbiont
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 15 days after sowing, the inoculation of 'A. brasilense' resulted in increased of diazotrophic bacteria density in the soil (15%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
PGPB inoculation increased root diazotrophic bacterial density at day 41 by 13%.
- Treatment
- inoculation of PGPB strains (AbV5 and SMR1)e0
- Interactor
- PGPBe0symbiont
- Outcome
- diazotrophic bacteria density in the maize rootse0
- Direction
- increasede0
- Value
- 13%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 41 days after sowing, the inoculation of PGPB strains (AbV5 and SMR1) resulted in increased of diazotrophic bacteria density in the maize roots (13%)”
Claim · model-written summary
H. seropedicae inoculation enhanced leaf nitrogen concentration by 12%.
- Organ / stage
- leaf tissuee0
- Treatment
- Seed inoculation with 'H. seropedicae'e0
- Interactor
- H. seropedicaeHerbaspirillum seropedicaee0symbiont
- Outcome
- nitrogen concentratione0
- Direction
- enhancese0
- Value
- 12%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seed inoculation with 'H. seropedicae' enhances the nitrogen concentration in the leaf tissue of maize (12%) under soil acidity conditions and without the nitrogen supply”
Claim · model-written summary
PGPB inoculation in acidic soil raised maize leaf phosphorus concentration.
- Organ / stage
- leaf tissuee0
- Treatment
- Inoculation of PGPBe0
- Interactor
- PGPBe0symbiont
- Outcome
- phosphorus concentratione0
- Direction
- highere0
- Qualifier
- acidic sandy soil (4.5 to 5.0 pH)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation of PGPB in acidic sandy soil (4.5 to 5.0 pH) resulted in higher phosphorus concentration in the leaf tissue of maize”
Claim · model-written summary
PGPB inoculation did not affect maize leaf CO2 assimilation rate.
- Treatment
- maize seed inoculation with PGPBe0
- Interactor
- PGPBe0symbiont
- Outcome
- Leaf CO2 assimilation ratee0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf CO2 assimilation rate was not affected by the maize seed inoculation with PGPB”
Claim · model-written summary
Soil acidity reduced maize stomatal conductance by 25%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soil acidity resulted in the reduction of stomatal conductance (-25%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
Soil acidity reduced maize leaf CO2 assimilation rate by 14%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soil acidity resulted in the reduction of stomatal conductance (-25%), leaf CO2 assimilation rate (-14%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
Soil acidity reduced maize leaf transpiration rate by 21%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soil acidity resulted in the reduction of stomatal conductance (-25%), leaf CO2 assimilation rate (-14%), leaf transpiration rate (-21%)”
e1“leaf gas exchange parameters of maize plants”
Claim · model-written summary
Soil acidity reduced maize water use efficiency by 6%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soil acidity resulted in the reduction of stomatal conductance (-25%), leaf CO2 assimilation rate (-14%), leaf transpiration rate (-21%) and water use efficiency (-6%) of maize plants”
Claim · model-written summary
NFb Lactate and NFb Malate media did not differentiate the two diazotrophic species.
Verbatim
e0“The NFb Lactate (selective for 'A. brasilense') and NFb Malate (selective for 'H. seropedicae') culture media were not effective in differentiating of the two diazotrophic species studied”
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See all 538 papers →8 of 10 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.