Abstract
Abstract Increased biomass and yield of plants grown under elevated [CO 2 ] often corresponds to decreased grain N concentration ([N]), diminishing nutritional quality of crops. Legumes through their symbiotic N 2 fixation may be better able to maintain biomass [N] and grain [N] under elevated [CO 2 ], provided N 2 fixation is stimulated by elevated [CO 2 ] in line with growth and yield. In Mediterranean‐type agroecosystems, N 2 fixation may be impaired by drought, and it is unclear whether elevated [CO 2 ] stimulation of N 2 fixation can overcome this impact in dry years. To address this question, we grew lentil under two [CO 2 ] (ambient ~400 ppm and elevated ~550 ppm) levels in a free‐air CO 2 enrichment facility over two growing seasons sharply contrasting in rainfall. Elevated [CO 2 ] stimulated N 2 fixation through greater nodule number (+27%), mass (+18%), and specific fixation activity (+17%), and this stimulation was greater in the high than in the low rainfall/dry season. Elevated [CO 2 ] depressed grain [N] (−4%) in the dry season. In contrast, grain [N] increased (+3%) in the high rainfall season under elevated [CO 2 ], as a consequence of greater post‐flowering N 2 fixation. Our results suggest that the benefit for N 2 fixation from elevated [CO 2 ] is high as long as there is enough soil water to continue N 2 fixation during grain filling.
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 8
Claim · model-written summary
Elevated CO2 increased lentil nodule number by 27%.
- Taxon
- lentil
Lens culinarist0 - Treatment
- Elevated [CO 2 ]e0
- Outcome
- nodule numbere0
- Direction
- greatere0
- Value
- +27%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated [CO 2 ] stimulated N 2 fixation through greater nodule number (+27%), mass (+18%), and specific fixation activity (+17%), and this stimulation was greater in the high than in the low rainfall/dry season.”
t0“lentil”
Claim · model-written summary
Elevated CO2 increased lentil nodule mass by 18%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated [CO 2 ] stimulated N 2 fixation through greater nodule number (+27%), mass (+18%), and specific fixation activity (+17%), and this stimulation was greater in the high than in the low rainfall/dry season.”
t0“lentil”
Claim · model-written summary
Elevated CO2 increased lentil specific fixation activity by 17%.
- Taxon
- lentilLens culinarist0
- Treatment
- Elevated [CO 2 ]e0
- Outcome
- specific fixation activitye0
- Direction
- greatere0
- Value
- +17%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated [CO 2 ] stimulated N 2 fixation through greater nodule number (+27%), mass (+18%), and specific fixation activity (+17%), and this stimulation was greater in the high than in the low rainfall/dry season.”
t0“lentil”
Claim · model-written summary
Elevated CO2 stimulation of lentil nitrogen fixation was greater in the high rainfall season.
- Taxon
- lentilLens culinarist0
- Treatment
- highe0
- Outcome
- this stimulatione0
- Direction
- greatere0
- Comparator
- low rainfall/dry seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this stimulation was greater in the high than in the low rainfall/dry season.”
t0“lentil”
Claim · model-written summary
Elevated CO2 reduced lentil grain nitrogen by 4% in the dry season.
- Taxon
- lentilLens culinarist0
- Treatment
- Elevated [CO 2 ]e0
- Outcome
- grain [N]e0
- Direction
- depressede0
- Value
- −4%e0
- Qualifier
- dry seasone0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Elevated [CO 2 ] depressed grain [N] (−4%) in the dry season.”
t0“lentil”
Claim · model-written summary
Elevated CO2 increased lentil grain nitrogen by 3% in the high rainfall season.
- Taxon
- lentilLens culinarist0
- Treatment
- elevated [CO 2 ]e0
- Outcome
- grain [N]e0
- Direction
- increasede0
- Value
- +3%e0
- Qualifier
- high rainfall seasone0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“grain [N] increased (+3%) in the high rainfall season under elevated [CO 2 ], as a consequence of greater post‐flowering N 2 fixation.”
t0“lentil”
Claim · model-written summary
Greater post flowering nitrogen fixation was presented as the explanation for higher lentil grain nitrogen in the high rainfall season.
- Taxon
- lentilLens culinarist0
- Treatment
- elevated [CO 2 ]e0
- Outcome
- grain [N]e0
- Qualifier
- greater post‐flowering N 2 fixatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“grain [N] increased (+3%) in the high rainfall season under elevated [CO 2 ], as a consequence of greater post‐flowering N 2 fixation.”
t0“lentil”
Claim · model-written summary
The authors concluded that adequate soil water is needed to sustain the elevated CO2 benefit to nitrogen fixation during grain filling.
- Taxon
- lentilLens culinarist0
- Outcome
- benefit for N 2 fixatione0
- Qualifier
- enough soil water to continue N 2 fixation during grain fillinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the benefit for N 2 fixation from elevated [CO 2 ] is high as long as there is enough soil water to continue N 2 fixation during grain filling.”
t0“lentil”
The same questions in other papers
co2 · symbiosis · Lens culinaris (lentil)Results agree
1 paper in the same direction as this paper
- positive
co2 · growth · Lens culinaris (lentil)Results agree
2 papers in the same direction as this paper
- 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.