Abstract
Effects of rhizosphere bacteria (RB), and rhizosphere bacteria with bacteria-feeding nematodes (RBN), on the composition of root exudate were examined after 2 weeks in gnotobiotic culture systems with rape seedlings (Brassica napus (L.)). The amounts of low molecular weight carbohydrates and of some free amino acids, per unit root dry weight, in the exudates were lower in the RB and RBN treatments than in the axenic control (R treatment). The growth of nematodes implied a production of bacterial cells in the RBN treatment 2.6 times that in the RB treatment. The bacterial growth in the RB treatment and the bacterial growth in combination with grazing by nematodes in the RBN treatment implied 24 and 63 times as much exudation of organic carbon, respectively, as in the R treatment. Most bacteria were attached to sand particles. The nematodes being suspension-feeders, decreased the proportion of free bacteria from 6% in the RB treatment to 2% in the RBN treatment. The numbers of attached bacteria in the RBN treratment were positively correlated with the numbers of nematodes, indicating stimulation of bacterial growth by the grazing.
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Claims 8
Claim · model-written summary
Root exudate carbohydrates and some free amino acids per unit root dry weight were lower with rhizosphere bacteria, with or without nematodes, than in axenic controls.
- Taxon
- rape
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napust0 - Treatment
- RB and RBN treatmentse0
- Outcome
- low molecular weight carbohydrates and of some free amino acidse0
- Direction
- lowere0
- Comparator
- axenic controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“The amounts of low molecular weight carbohydrates and of some free amino acids, per unit root dry weight, in the exudates were lower in the RB and RBN treatments than in the axenic control (R treatment).”
t0“rape”
Claim · model-written summary
Nematode growth implied bacterial cell production 2.6 times as high with nematodes as with bacteria alone.
- Taxon
- rapeBrassica napust0
- Outcome
- production of bacterial cellse0
- Direction
- 2.6 timese0
- Value
- 2.6 timese0
- Comparator
- RB treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The growth of nematodes implied a production of bacterial cells in the RBN treatment 2.6 times that in the RB treatment.”
t0“rape”
Claim · model-written summary
Bacterial growth without nematodes implied 24 times the organic carbon exudation of axenic controls.
- Taxon
- rapeBrassica napust0
- Treatment
- RB treatmente0
- Outcome
- exudation of organic carbone0
- Direction
- as muche0
- Value
- 24e0
- Comparator
- R treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The bacterial growth in the RB treatment and the bacterial growth in combination with grazing by nematodes in the RBN treatment implied 24 and 63 times as much exudation of organic carbon, respectively, as in the R treatment.”
t0“rape”
Claim · model-written summary
Bacterial growth with nematode grazing implied 63 times the organic carbon exudation of axenic controls.
- Taxon
- rapeBrassica napust0
- Treatment
- RBN treatmente0
- Outcome
- exudation of organic carbone0
- Direction
- as muche0
- Value
- 63 timese0
- Comparator
- R treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The bacterial growth in the RB treatment and the bacterial growth in combination with grazing by nematodes in the RBN treatment implied 24 and 63 times as much exudation of organic carbon, respectively, as in the R treatment.”
t0“rape”
Claim · model-written summary
Most rhizosphere bacteria were attached to sand particles.
- Taxon
- rapeBrassica napust0
- Outcome
- bacteria were attached to sand particlese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Most bacteria were attached to sand particles.”
t0“rape”
Claim · model-written summary
Nematodes reduced the proportion of free bacteria from 6% to 2%.
- Taxon
- rapeBrassica napust0
- Treatment
- nematodese0
- Outcome
- proportion of free bacteriae0
- Direction
- decreasede0
- Value
- 2%e0
- Qualifier
- 6%e0
- Comparator
- RB treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The nematodes being suspension-feeders, decreased the proportion of free bacteria from 6% in the RB treatment to 2% in the RBN treatment.”
t0“rape”
Claim · model-written summary
Attached bacterial numbers were positively correlated with nematode numbers in the RBN treatment.
- Taxon
- rapeBrassica napust0
- Treatment
- RBN treratmente0
- Outcome
- numbers of attached bacteriae0
- Direction
- positively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The numbers of attached bacteria in the RBN treratment were positively correlated with the numbers of nematodes, indicating stimulation of bacterial growth by the grazing.”
t0“rape”
Claim · model-written summary
The authors interpret the correlation as stimulation of bacterial growth by nematode grazing.
- Taxon
- rapeBrassica napust0
- Outcome
- stimulation of bacterial growthe0
- Qualifier
- by the grazinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“indicating stimulation of bacterial growth by the grazing.”
t0“rape”
The same questions in other papers
inoculation · quality: sugar starch · Brassica napus (oilseed rape)Results agree
1 paper in the same direction as this paper
- negative
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5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 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.