Abstract
Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.
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Claims 11
Claim · model-written summary
Nitrogen source did not significantly affect soybean dry matter except under sole ammonium at pH 4.5.
- Taxon
- Soybean
Glycine maxe0 - Treatment
- N-sourcee1
- Outcome
- Dry mattere1
- Direction
- not significantly affectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5.”
Claim · model-written summary
Nitrogen source did not significantly affect soybean total N accumulation except under sole ammonium at pH 4.5.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- N-sourcee1
- Outcome
- total N accumulatione1
- Direction
- not significantly affectede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5.”
Claim · model-written summary
Sole ammonium at pH 4.5 decreased soybean dry matter.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- solely with NH4+ at pH 4.5e1
- Outcome
- Dry mattere2
- Direction
- decreasese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“decreases in these parameters in plants supplied solely with NH4+ at pH 4.5”
e2“Dry matter and total N accumulation”
Claim · model-written summary
Sole ammonium at pH 4.5 decreased soybean total N accumulation.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- solely with NH4+ at pH 4.5e1
- Outcome
- total N accumulatione2
- Direction
- decreasese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“decreases in these parameters in plants supplied solely with NH4+ at pH 4.5”
e2“Dry matter and total N accumulation”
Claim · model-written summary
A greater ammonium proportion increased soybean shoot-to-root ratios at all pH levels.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- increased proportion [correction of proporiton] of NH4(+)-Ne1
- Outcome
- Shoot-to-root ratiose1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH.”
Claim · model-written summary
The absorbed proportion of each nitrogen ion increased with its proportion in solution at every pH.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- ratio of that ion increased in the nutrient solutione1
- Outcome
- proportion of either ion that was absorbede1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution.”
Claim · model-written summary
In mixed nitrogen solution at pH 6.0, soybean absorbed ammonium over nitrate at a 2:1 ratio.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0.”
Claim · model-written summary
Declining root-zone pH decreased soybean ammonium uptake.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- pH of the root-zone declinede1
- Outcome
- NH4+ uptakee1
- Direction
- decreasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased.”
Claim · model-written summary
Declining root-zone pH increased soybean nitrate uptake.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- pH of the root-zone declinede1
- Outcome
- NO3- uptakee1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased.”
Claim · model-written summary
The soybean ammonium-to-nitrate uptake ratio declined as root-zone pH decreased.
- Taxon
- SoybeanGlycine maxe0
- Treatment
- decreases in root-zone pHe1
- Outcome
- NH4+ to NO3- uptake ratioe1
- Direction
- declinede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH.”
Claim · model-written summary
Authors hypothesized that low pH inhibits ammonium-dependent soybean growth through reduced ammonium uptake and nitrogen stress.
- Taxon
- SoybeanGlycine maxe0
- Outcome
- inhibition of growthe1
- Qualifier
- a decline in NH4+ uptake and a consequential limitation of growth by N stresse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soybean plants (Glycine max [L.] Merr. cv Ransom)”
e1“the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.”
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See all 34 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.