Abstract
Legumes match the nodule number to the N demand of the plant. When a mutation in the regulatory mechanism deprives the plant of that ability, an excessive number of nodules are formed. These mutants show low productivity in the fields, mainly due to the high carbon burden caused through the necessity to supply numerous nodules. The objective of this study was to clarify whether through optimal conditions for growth and CO2 assimilation a higher nodule activity of a supernodulating mutant of Medicago truncatula (M. truncatula) can be induced. Several experimental approaches reveal that under the conditions of our experiments, the nitrogen fixation of the supernodulating mutant, designated as sunn (super numeric nodules), was not limited by photosynthesis. Higher specific nitrogen fixation activity could not be induced through short- or long-term increases in CO2 assimilation around shoots. Furthermore, a whole plant P depletion induced a decline in nitrogen fixation, however this decline did not occur significantly earlier in sunn plants, nor was it more intense compared to the wild-type. However, a distinctly different pattern of nitrogen fixation during the day/night cycles of the experiment indicates that the control of N2 fixing activity of the large number of nodules is an additional problem for the productivity of supernodulating mutants.
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Claims 6
Claim · model-written summary
Nitrogen fixation of the supernodulating mutant sunn was not limited by photosynthesis under the experimental conditions.
- Taxon
- Medicago truncatula
Medicago truncatulae2 - Material
- sunne1
- Outcome
- nitrogen fixatione1
- Qualifier
- under the conditions of our experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Several experimental approaches reveal that under the conditions of our experiments, the nitrogen fixation of the supernodulating mutant, designated as sunn (super numeric nodules), was not limited by photosynthesis”
e2“supernodulating mutant of Medicago truncatula”
Claim · model-written summary
Higher specific nitrogen fixation activity could not be induced by short- or long-term increases in CO2 assimilation around shoots.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- short- or long-term increases in CO2 assimilation around shootse3
- Outcome
- specific nitrogen fixation activitye3
- Direction
- could not be inducede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“supernodulating mutant of Medicago truncatula”
e3“Higher specific nitrogen fixation activity could not be induced through short- or long-term increases in CO2 assimilation around shoots”
Claim · model-written summary
Whole-plant P depletion induced a decline in nitrogen fixation.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- whole plant P depletione4
- Outcome
- nitrogen fixatione4
- Direction
- declinee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“supernodulating mutant of Medicago truncatula”
e4“Furthermore, a whole plant P depletion induced a decline in nitrogen fixation”
Claim · model-written summary
The decline in nitrogen fixation after P depletion did not occur significantly earlier in sunn plants than in the wild-type.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Material
- sunn plantse5
- Treatment
- whole plant P depletione4
- Outcome
- decline in nitrogen fixatione4
- Direction
- earliere5
- Comparator
- wild-typee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“supernodulating mutant of Medicago truncatula”
e4“Furthermore, a whole plant P depletion induced a decline in nitrogen fixation”
e5“this decline did not occur significantly earlier in sunn plants, nor was it more intense compared to the wild-type”
Claim · model-written summary
The decline in nitrogen fixation after P depletion was not more intense in sunn plants than in the wild-type.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Material
- sunn plantse5
- Treatment
- whole plant P depletione4
- Outcome
- decline in nitrogen fixatione4
- Direction
- more intensee5
- Comparator
- wild-typee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“supernodulating mutant of Medicago truncatula”
e4“Furthermore, a whole plant P depletion induced a decline in nitrogen fixation”
e5“this decline did not occur significantly earlier in sunn plants, nor was it more intense compared to the wild-type”
Claim · model-written summary
Nitrogen fixation followed a distinctly different pattern during the day/night cycles of the experiment.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Outcome
- pattern of nitrogen fixation during the day/night cyclese6
- Qualifier
- distinctly differente6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“supernodulating mutant of Medicago truncatula”
e6“a distinctly different pattern of nitrogen fixation during the day/night cycles of the experiment”
The same questions in other papers
co2 · symbiosis · Medicago truncatula (barrel medic)Positive and negative results
2 in the opposite direction
- positive
- positive
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.