Abstract
Root nodule senescence induced by nitrate and ammonium in Pisum sativum L. was defined by determining nitrogenase activity and leghemoglobin content with the acetylene reduction and pyridine hemochrome assays. Root systems supplied with 100 mm KNO(3) or 100 mm NH(4)Cl exhibited a decrease in nitrogenase activity followed by a decline in leghemoglobin content. Increasing the CO(2) concentration from 0.000320 atm to 0.00120 atm had no effect on the time course of root nodule senescence when 20 mm KNO(3) was supplied to the roots; in vitro nitrate reductase activity was detected in leaves and roots, but not bacteroids. Nitrate appeared in leaves, roots, and the nodule cytosol fraction but not bacteroids when 20 mm KNO(3) was supplied to roots. When nitrate entered through the shoots, however, no root nodule senescence was observed, and no nitrate was detected in root or nodule cytosol fractions although nitrate and nitrate reductase were found in leaves. The results suggest that nitrate does not induce root nodule senescence through competition between nitrate reductase and nitrogenase for products of photosynthesis.
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Claims 10
Claim · model-written summary
Root supplied KNO(3) decreased nodule nitrogenase activity.
- Taxon
- Pisum sativum L.
Lathyrus oleraceuse1 - Treatment
- 100 mm KNO(3)e0
- Outcome
- nitrogenase activitye0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root systems supplied with 100 mm KNO(3) or 100 mm NH(4)Cl exhibited a decrease in nitrogenase activity followed by a decline in leghemoglobin content”
e1“Pisum sativum L.”
Claim · model-written summary
Root supplied NH(4)Cl decreased nodule nitrogenase activity.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Treatment
- 100 mm NH(4)Cle0
- Outcome
- nitrogenase activitye0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root systems supplied with 100 mm KNO(3) or 100 mm NH(4)Cl exhibited a decrease in nitrogenase activity followed by a decline in leghemoglobin content”
e1“Pisum sativum L.”
Claim · model-written summary
Root supplied KNO(3) lowered nodule leghemoglobin content after nitrogenase activity decreased.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Treatment
- 100 mm KNO(3)e0
- Outcome
- leghemoglobin contente0
- Direction
- declinee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root systems supplied with 100 mm KNO(3) or 100 mm NH(4)Cl exhibited a decrease in nitrogenase activity followed by a decline in leghemoglobin content”
e1“Pisum sativum L.”
Claim · model-written summary
Root supplied NH(4)Cl lowered nodule leghemoglobin content after nitrogenase activity decreased.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Treatment
- 100 mm NH(4)Cle0
- Outcome
- leghemoglobin contente0
- Direction
- declinee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root systems supplied with 100 mm KNO(3) or 100 mm NH(4)Cl exhibited a decrease in nitrogenase activity followed by a decline in leghemoglobin content”
e1“Pisum sativum L.”
Claim · model-written summary
Raising CO(2) did not change the time course of nodule senescence under root supplied nitrate.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Treatment
- Increasing the CO(2) concentration from 0.000320 atm to 0.00120 atme0
- Outcome
- time course of root nodule senescencee0
- Direction
- no effecte0
- Qualifier
- 20 mm KNO(3)e0
- Comparator
- 0.000320 atme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the CO(2) concentration from 0.000320 atm to 0.00120 atm had no effect on the time course of root nodule senescence when 20 mm KNO(3) was supplied to the roots”
e1“Pisum sativum L.”
Claim · model-written summary
Nitrate reductase activity was detected in leaves and roots but not bacteroids.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Organ / stage
- leaves and rootse0
- Outcome
- nitrate reductase activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrate reductase activity was detected in leaves and roots, but not bacteroids”
e1“Pisum sativum L.”
Claim · model-written summary
After root nitrate supply, nitrate was present in leaves, roots and nodule cytosol but absent from bacteroids.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Treatment
- 20 mm KNO(3)e0
- Outcome
- Nitrate appeared in leaves, roots, and the nodule cytosol fraction but not bacteroidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate appeared in leaves, roots, and the nodule cytosol fraction but not bacteroids when 20 mm KNO(3) was supplied to roots”
e1“Pisum sativum L.”
Claim · model-written summary
Nitrate entry via shoots did not induce root nodule senescence.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Treatment
- nitrate entered through the shootse0
- Outcome
- root nodule senescencee0
- Direction
- no root nodule senescencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When nitrate entered through the shoots, however, no root nodule senescence was observed”
e1“Pisum sativum L.”
Claim · model-written summary
With shoot nitrate entry, nitrate was not detected in roots or nodule cytosol although nitrate and nitrate reductase were found in leaves.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Organ / stage
- root or nodule cytosol fractionse0
- Outcome
- no nitrate was detected in root or nodule cytosol fractionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no nitrate was detected in root or nodule cytosol fractions although nitrate and nitrate reductase were found in leaves”
e1“Pisum sativum L.”
Claim · model-written summary
The authors infer nitrate does not cause senescence through nitrate reductase competing with nitrogenase for photosynthates.
- Taxon
- Pisum sativum L.Lathyrus oleraceuse1
- Outcome
- root nodule senescencee0
- Qualifier
- competition between nitrate reductase and nitrogenase for products of photosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrate does not induce root nodule senescence through competition between nitrate reductase and nitrogenase for products of photosynthesis”
e1“Pisum sativum L.”
The same questions in other papers
nitrogen · symbiosis · Lathyrus oleraceus (pea)Results differ
15 papers in the same direction as this paper · 9 in the opposite direction
- negative
- negative
- positive
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See all 25 papers →co2 · symbiosis · Lathyrus oleraceus (pea)Positive and negative results
4 in the opposite direction
- positive
- positive
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See all 5 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.