Abstract
Abstract Variations in response to ammonium and nitrate by different plant species including corn ( Zea mays L.) quires further definition. Corn was grown in nutrient solutions under greenhouse conditions to investigate (1) uptake of ammonium and nitrate from the solutions and (2) the effect of ammonium and nitrate on growth, nitrate reductase activity, and accumulation of total N and nitrate in leaves, stems, and roots at four stages of development (21, 28, 40, and 47 days after planting). Uptake was determined by following the disappearance of ammonium‐N and nitrate‐N from nutrient solutions in which N was supplied in various combinations and rates. The nutrient solution treatments were as follows (ppm NO 3 ‐ ‐N/ ppm NH 4 + ‐N): 0/50, 0/100, 0/150, 50/0, 100/0, 150/0, 25/75, 50/50 and 75/25. Fresh and dry weights per plant generally increased more rapidly when plants were provided 100 ppm of N as a combination of nitrate‐N and ammonium‐N (25/75, 50/50, or 75/25) than wherein 100 ppm of either nitrate‐N (100/0) or ammonium‐N (0/100) was supplied alone. When both nitrate‐N and ammonium‐N were supplied, uptake rates of the two forms were similar. Uptake of nitrate was not retarded by the presence of ammonium, but assimilation of nitrate into organic N was retarded by ammonium. When both forms of N were absorbed, ammonium was used preferentially for synthesis of amino acids and protein. Nitrate reductase activity was localized principally in the leaf blades and tended to be highest in plants provided a combination of nitrate‐N and ammonium‐N. Total N in the leaf and root tissues generally was higher in plants grown on ammonium alone or in combination with nitrate than in plants grown on nitrate alone. More nitrate accumulated in stem tissue than in leaf or root tissues. Amino acid composition of leaf tissue was not affected by the N treatments.
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Claims 10
Claim · model-written summary
Mixed nitrate and ammonium at 100 ppm N increased fresh and dry plant weight faster than either form alone.
- Treatment
- 100 ppm of N as a combination of nitrate‐N and ammonium‐N (25/75, 50/50, or 75/25)e0
- Outcome
- Fresh and dry weights per plante0
- Direction
- increased more rapidlye0
- Comparator
- 100 ppm of either nitrate‐N (100/0) or ammonium‐N (0/100)e0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fresh and dry weights per plant generally increased more rapidly when plants were provided 100 ppm of N as a combination of nitrate‐N and ammonium‐N (25/75, 50/50, or 75/25) than wherein 100 ppm of either nitrate‐N (100/0) or ammonium‐N (0/100) was supplied alone.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
When both N forms were supplied, their uptake rates were similar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When both nitrate‐N and ammonium‐N were supplied, uptake rates of the two forms were similar.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
Ammonium did not retard nitrate uptake.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Uptake of nitrate was not retarded by the presence of ammonium, but assimilation of nitrate into organic N was retarded by ammonium.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
Ammonium retarded assimilation of nitrate into organic nitrogen.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Uptake of nitrate was not retarded by the presence of ammonium, but assimilation of nitrate into organic N was retarded by ammonium.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
When both nitrogen forms were absorbed, ammonium was preferentially used to synthesize amino acids and protein.
- Outcome
- ammonium was used preferentially for synthesis of amino acids and proteine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When both forms of N were absorbed, ammonium was used preferentially for synthesis of amino acids and protein.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
Nitrate reductase activity was mainly in leaf blades.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate reductase activity was localized principally in the leaf blades and tended to be highest in plants provided a combination of nitrate‐N and ammonium‐N.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
A mixture of nitrate and ammonium tended to yield the highest nitrate reductase activity.
- Treatment
- a combination of nitrate‐N and ammonium‐Ne0
- Outcome
- Nitrate reductase activitye0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate reductase activity was localized principally in the leaf blades and tended to be highest in plants provided a combination of nitrate‐N and ammonium‐N.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
Leaf and root total N was generally higher with ammonium alone or mixed with nitrate than with nitrate alone.
- Treatment
- ammonium alone or in combination with nitratee0
- Outcome
- Total N in the leaf and root tissuese0
- Direction
- highere0
- Comparator
- nitrate alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total N in the leaf and root tissues generally was higher in plants grown on ammonium alone or in combination with nitrate than in plants grown on nitrate alone.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
Stem tissue accumulated more nitrate than leaf or root tissue.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“More nitrate accumulated in stem tissue than in leaf or root tissues.”
t0“Corn (Zea mays L.)”
Claim · model-written summary
Nitrogen treatments did not affect leaf amino acid composition.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Amino acid composition of leaf tissue was not affected by the N treatments.”
t0“Corn (Zea mays L.)”
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