Abstract
ABSTRACT The addition of carbonates to a nutrient solution to alleviate ammonium (NH4 +) toxicity in hydroponically-grown cucumber (Cucumis sativus L.) plants was investigated. Stable isotopes [nitrogen (15N) and carbon (13C)] were used to assess the uptake of nitrogen [NH4 + or nitrate (NO3 −)] as well as carbon [bicarbonate (HCO3 −)/carbonate (CO3 2−)] by the roots. Ammonium as the sole N source at 5 mM decreased plant fresh weights compared to NO3 −. However, at lower concentrations of NH4 + (25% of 5 mM total N), growth was increased compared to NO3 − alone. Inorganic C enrichment [calcium carbonate (CaCO3)] of the nutrient solution increased the fresh weight of NH4 + grown plants with up to 150% relative to control plants receiving calcium hydroxide [Ca(OH)2] for pH regulation. Root 15N enrichment was lower in 15NH4 + supplied plants compared to 15NO3 −, while the 13C enrichment in leaves was increased by NH4 + nutrition compared to NO3 − or NH4NO3. The enhanced C capture was associated with high PEPCase activity in the roots. It is concluded that inorganic carbon enrichment of the root medium may alleviate NH4 + toxicity via increased synthesis of C skeletons and, accordingly, increased capacity for NH4 + assimilation and N export to the shoots.
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Claims 7
Claim · model-written summary
Ammonium as the sole N source at 5 mM decreased plant fresh weight compared with nitrate.
- Taxon
- cucumber
Cucumis sativust0 - Treatment
- Ammonium as the sole N source at 5 mMe0
- Outcome
- plant fresh weightse0
- Direction
- decreasede0
- Comparator
- NO3 −e0
- Setting
- hydroponically-growne7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e0“Ammonium as the sole N source at 5 mM decreased plant fresh weights compared to NO3 −”
e7“hydroponically-grown cucumber (Cucumis sativus L.) plants”
Claim · model-written summary
At lower NH4+ concentrations (25% of 5 mM total N), growth increased compared with nitrate alone.
- Taxon
- cucumberCucumis sativust0
- Treatment
- at lower concentrations of NH4 + (25% of 5 mM total N)e1
- Outcome
- growthe1
- Direction
- increasede1
- Comparator
- NO3 − alonee1
- Setting
- hydroponically-growne7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e1“However, at lower concentrations of NH4 + (25% of 5 mM total N), growth was increased compared to NO3 − alone”
e7“hydroponically-grown cucumber (Cucumis sativus L.) plants”
Claim · model-written summary
Calcium carbonate enrichment of the nutrient solution increased fresh weight of NH4+-grown plants by up to 150% relative to calcium hydroxide controls.
- Taxon
- cucumberCucumis sativust0
- Treatment
- calcium carbonate (CaCO3)e2
- Outcome
- fresh weighte2
- Direction
- increasede2
- Value
- up to 150%e2
- Comparator
- calcium hydroxide [Ca(OH)2]e2
- Setting
- hydroponically-growne7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e2“Inorganic C enrichment [calcium carbonate (CaCO3)] of the nutrient solution increased the fresh weight of NH4 + grown plants with up to 150% relative to control plants receiving calcium hydroxide [Ca(OH)2] for pH regulation”
e7“hydroponically-grown cucumber (Cucumis sativus L.) plants”
Claim · model-written summary
Root 15N enrichment was lower in plants supplied with 15NH4+ than with 15NO3-.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 15NH4 +e3
- Outcome
- Root 15N enrichmente3
- Direction
- lowere3
- Comparator
- 15NO3 −e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e3“Root 15N enrichment was lower in 15NH4 + supplied plants compared to 15NO3 −”
Claim · model-written summary
NH4+ nutrition increased the 13C enrichment in leaves compared with nitrate or ammonium nitrate.
- Taxon
- cucumberCucumis sativust0
- Treatment
- NH4 + nutritione4
- Outcome
- 13C enrichment in leavese4
- Direction
- increasede4
- Comparator
- NO3 − or NH4NO3e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e4“the 13C enrichment in leaves was increased by NH4 + nutrition compared to NO3 − or NH4NO3”
Claim · model-written summary
Enhanced carbon capture was associated with high PEPCase activity in cucumber roots.
- Taxon
- cucumberCucumis sativust0
- Organ / stage
- rootse5
- Gene
- PEPCasee5
- Outcome
- PEPCase activitye5
- Direction
- highe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e5“The enhanced C capture was associated with high PEPCase activity in the roots”
Claim · model-written summary
Inorganic carbon enrichment of the root medium may alleviate NH4+ toxicity through increased synthesis of C skeletons.
- Taxon
- cucumberCucumis sativust0
- Treatment
- inorganic carbon enrichment of the root mediume6
- Outcome
- alleviate NH4 + toxicitye6
- Qualifier
- via increased synthesis of C skeletonse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Cucumber Plants”
e6“It is concluded that inorganic carbon enrichment of the root medium may alleviate NH4 + toxicity via increased synthesis of C skeletons”
The same questions in other papers
nitrogen · growth · Cucumis sativus (cucumber)Positive and negative results
16 papers in the same direction as this paper · 21 in the opposite direction
- positive
- positive
- positive
34 papers more in this group
See all 38 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.