Abstract
Seven crop species, including maize, sorghum, rice, wheat, barley, peanut and soybean, were grown hydroponically with either nitrate or ammonium N at a concentration of 150 ppm. Rates of seedling growth were determined to study the effect of N sources on the performances of carbon metabolism. As ammonium N could enhance the activity of PEP carboxylase in the roots of many crops, attempts had been made to clarify the characteristics of this enzyme in order to provide basis for further studies. Experimental results showed that crops grew better in nitrate N than in ammonium N medium. However, shoots of rice and wheat gained more fresh weight when treated with ammonium N which was different from the results on maize, sorghum and peanut, indicating difference in response to N sources among plant species. Amnionium N could enhance the activity of PEP carboxylase of various crops. The increase was 8-61% in the leaf blade and as high as 4.5 folds in the root. PEP carboxylase extracted from the roots of Tainung 67 rice with the methods employed in this experiment was extremely stable. No decrease in enzyme activity was observed up to 7 hrs after extraction. Optimal pH for rice root PEP carboxylase was between 8.0 and 8.5 with either Tris-HCl (100 mM) or Hepes-KOH(50 mM) buffer. Kinetic study showed that the response curves of velocity versus substrate (PEP) concentration was hyperbolic at pH 8.0 and sigmoid at pH 7.0. Reciprocal plots of the data was linear, indicatng Michaelis-Menten kinetics. Km value for PEP was calculated to be 0.16 mM at pH 8.0. Preliminary results suggested that the ammonium-N responsive root PEP carboxylase was similar to the same enzyme from leaf blades of C3 plants in many aspects. As PEP plays a very important role in carbon metabolism, and in view that ammonium-N at a very low concentration (e. g., 1 ppm) could enhance significantly the activity of root PEP carboxylase, the finding of this experiment could be utilized for further study on the interaction of N and carbon metabolism in plants.
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Claims 12
Claim · model-written summary
Crops grew better with nitrate N than with ammonium N.
Verbatim
t0“Different Crop Species”
e1“Experimental results showed that crops grew better in nitrate N than in ammonium N medium”
Claim · model-written summary
Shoots of rice and wheat gained more fresh weight with ammonium N.
- Taxon
- rice and wheat
Oryza sativa
Triticum aestivume2 - Organ / stage
- shootse2
- Treatment
- ammonium Ne2
- Outcome
- fresh weighte2
- Direction
- gained moree2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Different Crop Species”
e2“shoots of rice and wheat gained more fresh weight when treated with ammonium N which was different from the results on maize, sorghum and peanut”
Claim · model-written summary
Ammonium N increased PEP carboxylase activity of various crops by 8-61% in the leaf blade.
- Taxon
- various cropse3
- Organ / stage
- leaf bladee4
- Treatment
- Amnionium Ne3
- Gene
- PEP carboxylasee3
- Outcome
- activity of PEP carboxylasee3
- Direction
- increasee4
- Value
- 8-61%e4
Not reportedComparator
Verbatim
t0“Different Crop Species”
e3“Amnionium N could enhance the activity of PEP carboxylase of various crops”
e4“The increase was 8-61% in the leaf blade and as high as 4.5 folds in the root”
Claim · model-written summary
Ammonium N increased PEP carboxylase activity in the root by as much as 4.5 folds.
- Taxon
- various cropse3
- Organ / stage
- roote4
- Treatment
- Amnionium Ne3
- Gene
- PEP carboxylasee3
- Outcome
- activity of PEP carboxylasee3
- Direction
- increasee4
- Value
- 4.5 foldse4
Not reportedComparator
Verbatim
t0“Different Crop Species”
e3“Amnionium N could enhance the activity of PEP carboxylase of various crops”
e4“The increase was 8-61% in the leaf blade and as high as 4.5 folds in the root”
Claim · model-written summary
Ammonium-N at a very low concentration significantly enhanced root PEP carboxylase activity.
- Taxon
- Crop Speciest0
- Treatment
- ammonium-N at a very low concentration (e. g., 1 ppm)e5
- Gene
- PEP carboxylasee5
- Outcome
- activity of root PEP carboxylasee5
- Direction
- enhancee5
Not reportedComparator
Verbatim
t0“Different Crop Species”
e5“ammonium-N at a very low concentration (e. g., 1 ppm) could enhance significantly the activity of root PEP carboxylase”
Claim · model-written summary
Optimal pH for rice root PEP carboxylase was between 8.0 and 8.5 in Tris-HCl or Hepes-KOH buffer.
- Taxon
- riceOryza sativae6
- Organ / stage
- roote6
- Gene
- PEP carboxylasee6
- Outcome
- Optimal pHe6
- Value
- between 8.0 and 8.5e6
- Qualifier
- Tris-HCl (100 mM) or Hepes-KOH(50 mM) buffere6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Different Crop Species”
e6“Optimal pH for rice root PEP carboxylase was between 8.0 and 8.5 with either Tris-HCl (100 mM) or Hepes-KOH(50 mM) buffer”
Claim · model-written summary
PEP carboxylase from the roots of Tainung 67 rice showed no decrease in enzyme activity up to 7 hours after extraction.
- Taxon
- riceOryza sativae7
- Material
- Tainung 67e7
- Organ / stage
- rootse7
- Outcome
- enzyme activitye7
- Direction
- No decreasee7
- Qualifier
- up to 7 hrs after extractione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Different Crop Species”
e7“PEP carboxylase extracted from the roots of Tainung 67 rice with the methods employed in this experiment was extremely stable. No decrease in enzyme activity was observed up to 7 hrs after extraction”
Claim · model-written summary
The velocity versus PEP concentration response curve was hyperbolic at pH 8.0.
Verbatim
t0“Different Crop Species”
e7“the response curves of velocity versus substrate (PEP) concentration was hyperbolic at pH 8.0 and sigmoid at pH 7.0”
Claim · model-written summary
The velocity versus PEP concentration response curve was sigmoid at pH 7.0.
Verbatim
t0“Different Crop Species”
e7“the response curves of velocity versus substrate (PEP) concentration was hyperbolic at pH 8.0 and sigmoid at pH 7.0”
Claim · model-written summary
Reciprocal plots of the data were linear, indicating Michaelis-Menten kinetics.
Verbatim
t0“Different Crop Species”
e7“Reciprocal plots of the data was linear, indicatng Michaelis-Menten kinetics”
Claim · model-written summary
The Km for PEP of root PEP carboxylase was 0.16 mM at pH 8.0.
Verbatim
t0“Different Crop Species”
e7“Km value for PEP was calculated to be 0.16 mM at pH 8.0”
Claim · model-written summary
The ammonium-N responsive root PEP carboxylase was similar to leaf-blade PEP carboxylase of C3 plants in many aspects.
Verbatim
t0“Different Crop Species”
e7“the ammonium-N responsive root PEP carboxylase was similar to the same enzyme from leaf blades of C3 plants in many aspects”
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See all 551 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.