Abstract
The natural (15)N/(14)N isotope composition (δ(15)N) of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ(15)N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L.) plants were subjected to distinct conditions of [CO2] (400 vs. 700 μmol mol(-1)), temperature (ambient vs. ambient +4°C) and water availability (fully watered vs. water deficiency-WD). As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ(15)N in leaves, stems, roots, and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP) contents detected at 700 μmol mol(-1) [CO2] and WD conditions. In summary, leaf δ(15)N provides relevant information integrating parameters which condition plant responsiveness (e.g., photosynthesis, TSP, N demand, and water transpiration) to environmental conditions.
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Claims 8
Claim · model-written summary
Elevated CO2 stimulated photosynthetic rates and growth.
- Taxon
- alfalfa
Medicago sativae1 - Treatment
- increased [CO2]e0
- Outcome
- photosynthetic rates and plant growthe0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased [CO2] and temperature stimulated photosynthetic rates and plant growth”
e1“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
Higher temperature stimulated photosynthetic rates and growth.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- temperaturee0
- Outcome
- photosynthetic rates and plant growthe0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased [CO2] and temperature stimulated photosynthetic rates and plant growth”
e1“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
Water deficiency negatively affected photosynthesis and growth.
- Taxon
- alfalfaMedicago sativae2
- Treatment
- WDe0
- Outcome
- photosynthetic rates and plant growthe1
- Direction
- negatively affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“whereas these parameters were negatively affected by WD”
e1“photosynthetic rates and plant growth”
e2“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
Leaves were the most representative organs for the response to increased CO2 and water deficit.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- leavese0
- Treatment
- increased [CO2] and WDe0
- Outcome
- most representative organs of the plant responsee0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaves were the most representative organs of the plant response to increased [CO2] and WD”
e1“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
Higher CO2 and water deficit were associated with depletion of heavier nitrogen isotopes.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- higher [CO2] and WD conditionse0
- Outcome
- heavier N isotopese0
- Direction
- Depletione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions”
e1“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
The isotope depletion reflected decreased transpiration rates.
- Taxon
- alfalfaMedicago sativae1
- Outcome
- Depletion of heavier N isotopese0
- Direction
- Depletione0
- Qualifier
- decreased transpiration ratese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates”
e1“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
Leaf nitrogen and total soluble protein contents decreased at elevated CO2 and under water deficit.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- leafe0
- Treatment
- 700 μmol mol(-1) [CO2] and WD conditionse0
- Outcome
- leaf N and total soluble protein (TSP) contentse0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased leaf N and total soluble protein (TSP) contents detected at 700 μmol mol(-1) [CO2] and WD conditions”
e1“alfalfa (Medicago sativa L.) plants”
Claim · model-written summary
Leaf isotope composition integrates physiological responsiveness to environmental conditions.
- Taxon
- alfalfaMedicago sativae1
- Organ / stage
- leafe0
- Outcome
- plant responsivenesse0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf δ(15)N provides relevant information integrating parameters which condition plant responsiveness (e.g., photosynthesis, TSP, N demand, and water transpiration) to environmental conditions”
e1“alfalfa (Medicago sativa L.) plants”
The same questions in other papers
co2 · physiology: photosynthesis · Medicago sativa (alfalfa)Results differ
6 papers in the same direction as this paper · 3 in the opposite direction
- positive
- negative
- no effect
6 papers more in this group
See all 10 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.