Abstract
Abstract Many plant species are characterized by pronounced sensitivity to sole ammonium supply and exhibit growth depression and particularly reduced leaf growth rates. Stress symptoms under sole ammonium supply may be related to perturbation of photosynthetic processes, e.g. , low rates of net CO 2 assimilation, low quantum yield, reduced stomatal conductance, and carboxylation capacity. The results of three experiments with French bean plants supplied with an N concentration of 5 mM illustrate significantly lower dry mass and specific leaf area, reduced leaf expansion, and higher chlorophyll and N content of ammonium‐ compared to nitrate‐supplied plants. Light‐saturated rates of CO 2 assimilation (A max ) per unit leaf area were higher under ammonium compared to nitrate supply while no significant effects of N form on quantum yield and A max per unit leaf weight and chlorophyll were found. Maximal carboxylation (V cmax ) and electron‐transport (J Max ) rates were significantly higher under ammonium supply only in one of three experiments. V cmax was linearly related to total leaf N, the slope of the regression was similar with both N forms, the x‐axis intercept was significantly higher for ammonium‐ compared to nitrate‐supplied plants. The ratio V cmax : J Max was not affected by N form. It is concluded that ammonium supply had no negative effects on the operation of photosynthetic protein‐enzyme complexes.
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Claims 11
Claim · model-written summary
Ammonium reduced dry mass, specific leaf area and leaf expansion relative to nitrate.
- Taxon
- Phaseolus vulgaris L.
Phaseolus vulgarist0 - Treatment
- ammoniume0
- Outcome
- dry mass and specific leaf area, reduced leaf expansione0
- Direction
- lowere0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly lower dry mass and specific leaf area, reduced leaf expansion, and higher chlorophyll and N content of ammonium‐ compared to nitrate‐supplied plants”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Ammonium increased chlorophyll and N content relative to nitrate.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- ammoniume0
- Outcome
- chlorophyll and N contente0
- Direction
- highere0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher chlorophyll and N content of ammonium‐ compared to nitrate‐supplied plants”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Area-based light-saturated CO2 assimilation was higher with ammonium than nitrate.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- ammoniume0
- Outcome
- CO 2 assimilation (A max ) per unit leaf areae0
- Direction
- highere0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light‐saturated rates of CO 2 assimilation (A max ) per unit leaf area were higher under ammonium compared to nitrate supply”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Nitrogen form had no significant effect on quantum yield.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- N forme0
- Outcome
- quantum yielde0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no significant effects of N form on quantum yield and A max per unit leaf weight and chlorophyll were found”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Nitrogen form had no significant effect on mass- and chlorophyll-based A max.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- N forme0
- Outcome
- A max per unit leaf weight and chlorophylle0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no significant effects of N form on quantum yield and A max per unit leaf weight and chlorophyll were found”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
V cmax and J Max were higher under ammonium in one of three experiments.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- ammonium supplye0
- Outcome
- Maximal carboxylation (V cmax ) and electron‐transport (J Max ) ratese0
- Direction
- highere0
- Qualifier
- only in one of three experimentse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximal carboxylation (V cmax ) and electron‐transport (J Max ) rates were significantly higher under ammonium supply only in one of three experiments”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
V cmax was linearly related to total leaf N.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Compound
- total leaf Ne0
- Outcome
- V cmaxe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“V cmax was linearly related to total leaf N”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
The V cmax versus leaf N slope was similar for both N forms.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- N formse0
- Outcome
- slope of the regressione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the slope of the regression was similar with both N forms”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
The x-axis intercept was higher with ammonium than nitrate.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- ammoniume0
- Outcome
- x‐axis intercepte0
- Direction
- highere0
- Comparator
- nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the x‐axis intercept was significantly higher for ammonium‐ compared to nitrate‐supplied plants”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Nitrogen form did not affect the V cmax:J Max ratio.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- N forme0
- Outcome
- ratio V cmax : J Maxe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ratio V cmax : J Max was not affected by N form”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
The authors concluded ammonium had no negative effect on photosynthetic protein-enzyme complexes.
- Taxon
- Phaseolus vulgaris L.Phaseolus vulgarist0
- Treatment
- ammonium supplye0
- Outcome
- operation of photosynthetic protein‐enzyme complexese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ammonium supply had no negative effects on the operation of photosynthetic protein‐enzyme complexes”
t0“Phaseolus vulgaris L.”
The same questions in other papers
nitrogen · physiology: photosynthesis · Phaseolus vulgaris (common bean)Positive and negative results
3 papers in the same direction as this paper · 3 in the opposite direction · 2 reporting no difference from an alternative
- negative
- negative
- negative
5 papers more in this group
See all 9 papers →nitrogen · growth · Phaseolus vulgaris (common bean)Positive and negative results
15 papers in the same direction as this paper · 44 in the opposite direction
- positive
- positive
- positive
56 papers more in this group
See all 60 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.