Abstract
ABSTRACT Two hydroponic experiments were carried out to investigate the effects of nitrogen (N) levels and forms on the oxalate concentrations of different form in edible parts of spinach. Nitrogen was supplied at five levels (4, 8, 12, 16, 20 mM) in Experiment 1 and five ratios of nitrate (NO3 −) to ammonium (NH4 +) (100/0, 75/25, 50/50, 25/75, 0/100) at a total N of 8 mM in Experiment 2. Biomass of spinach increased markedly from 4 mM to 8 mM N and reached the flat with further increase in N. The total oxalate and soluble oxalate in leaves and shoots (edible parts) increased significantly with increasing N levels from 4 to 12 mM, while the total oxalate and insoluble oxalate decreased markedly when N level was further increased from 12 to 20 mM. Oxalates of different forms in petioles increased first and then decreased and elevated again with increasing nitrogen levels. In the second experiment, decreasing NO3 −/NH4 + ratios markedly increased at first and then significantly decreased the biomass of spinach plants and the maximum biomass was recorded in the treatment of the NO3 −/NH4 + ratio of 50:50. The oxalate concentrations of different form in leaves and shoots were all decreased obviously as the ratio of NO3 −/NH4 + decreased from 100:0 to 0:100. Concentrations of total oxalate and soluble oxalate in petioles could be reduced by increasing ammonium proportion and were the lowest as the ratio of NO3 −/NH4 + was 50:50 and insoluble oxalate decreased as nitrate/ammonium ratio decreased. The concentrations of oxalate forms in leaves were all higher than those in petioles and soluble oxalate was predominant form of oxalates in both trials. It is evident that high biomass of spinach can be achieved and oxalate concentrations of different forms can be reduced by modulating N levels and NO3 −/NH4 + ratio, so this will benefit for human health especially for those people with a history of calcium oxalate kidney stones.
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Claims 12
Claim · model-written summary
Spinach biomass rose between 4 and 8 mM nitrogen.
- Taxon
- spinach
Spinacia oleraceae0 - Treatment
- 8 mM Ne0
- Outcome
- Biomasse0
- Direction
- increased markedlye0
- Comparator
- 4 mMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biomass of spinach increased markedly from 4 mM to 8 mM N”
Claim · model-written summary
Further nitrogen increases produced a biomass plateau.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- further increase in Ne0
- Outcome
- reached the flate0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reached the flat with further increase in N.”
t0“spinach”
Claim · model-written summary
Leaf and shoot total and soluble oxalate increased as N rose from 4 to 12 mM.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- leaves and shootse0
- Treatment
- increasing N levels from 4 to 12 mMe0
- Outcome
- total oxalate and soluble oxalate in leaves and shootse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The total oxalate and soluble oxalate in leaves and shoots (edible parts) increased significantly with increasing N levels from 4 to 12 mM”
t0“spinach”
Claim · model-written summary
Total and insoluble oxalate fell as N rose from 12 to 20 mM.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- N level was further increased from 12 to 20 mMe0
- Outcome
- total oxalate and insoluble oxalatee0
- Direction
- decreased markedlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the total oxalate and insoluble oxalate decreased markedly when N level was further increased from 12 to 20 mM.”
t0“spinach”
Claim · model-written summary
Petioles showed an increase, decrease, then increase in oxalate forms as N increased.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- petiolese0
- Treatment
- increasing nitrogen levelse0
- Outcome
- Oxalates of different forms in petiolese0
- Direction
- increased first and then decreased and elevated againe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxalates of different forms in petioles increased first and then decreased and elevated again with increasing nitrogen levels.”
t0“spinach”
Claim · model-written summary
Biomass first rose then fell as the nitrate/ammonium ratio decreased.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- decreasing NO3 −/NH4 + ratiose0
- Outcome
- biomasse0
- Direction
- increased at first and then significantly decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreasing NO3 −/NH4 + ratios markedly increased at first and then significantly decreased the biomass of spinach plants”
Claim · model-written summary
The maximum spinach biomass occurred at a 50:50 nitrate/ammonium ratio.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- NO3 −/NH4 + ratio of 50:50e0
- Outcome
- maximum biomasse0
- Direction
- maximume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maximum biomass was recorded in the treatment of the NO3 −/NH4 + ratio of 50:50.”
t0“spinach”
Claim · model-written summary
All oxalate forms in leaves and shoots decreased as nitrate/ammonium ratio fell from 100:0 to 0:100.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- ratio of NO3 −/NH4 + decreased from 100:0 to 0:100e0
- Outcome
- oxalate concentrations of different form in leaves and shootse0
- Direction
- decreased obviouslye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The oxalate concentrations of different form in leaves and shoots were all decreased obviously as the ratio of NO3 −/NH4 + decreased from 100:0 to 0:100.”
t0“spinach”
Claim · model-written summary
Increasing ammonium proportion reduced total and soluble petiole oxalate, lowest at 50:50 nitrate/ammonium.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- increasing ammonium proportione0
- Outcome
- total oxalate and soluble oxalate in petiolese0
- Direction
- reducede0
- Qualifier
- NO3 −/NH4 + was 50:50e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentrations of total oxalate and soluble oxalate in petioles could be reduced by increasing ammonium proportion and were the lowest as the ratio of NO3 −/NH4 + was 50:50”
t0“spinach”
Claim · model-written summary
Insoluble petiole oxalate decreased as nitrate/ammonium ratio decreased.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- nitrate/ammonium ratio decreasede0
- Outcome
- insoluble oxalatee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“insoluble oxalate decreased as nitrate/ammonium ratio decreased.”
t0“spinach”
Claim · model-written summary
Leaf concentrations of all oxalate forms exceeded petiole concentrations.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- leavese0
- Outcome
- concentrations of oxalate formse0
- Direction
- highere0
- Comparator
- petiolese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentrations of oxalate forms in leaves were all higher than those in petioles”
t0“spinach”
Claim · model-written summary
Soluble oxalate was the predominant form in both trials.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- soluble oxalate was predominant form of oxalatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soluble oxalate was predominant form of oxalates in both trials.”
t0“spinach”
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See all 40 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.