Abstract
We examined the effect of drought stress on proline accumulation, nitrogenase activity and activities of enzymes related to proline metabolism in soybean (Glycine max [L.] Merr.) nodules. Nitrogenase (C2H2 reducing) activity was inhibited 90% or more as a result of drought stress. This inhibition was substantially reversed after a 4 h recovery period. Pyrroline-5-carboxylate reductase activity in extracts of drought-stressed nodules from 25-d-old plants was 55% higher than in unstressed nodules, but the same activity in preparations from 55-d-old plants was similar to that of control plants. Extracts of recovering nodules on plants of both ages had activities near those of controls. Drought stress increased the activity of the pentose phosphate pathway by about 65% in extracts of nodules from 55-d-old plants, but there was no effect in extracts of nodules from younger plants (25-d-old). Proline dehydrogenase activity was 3.7 and 1.6 times higher in bacteroids isolated from nodules taken from 25- and 55-d-old stressed plants, respectively, than in comparable control bacteroids. This activity remained high in bacteroids from both sets of recovering nodules. The amount of proline in extracts from stressed nodules was 3- to 4-fold higher than in unstressed nodules, despite increased proline dehydrogenase activity and remained high in nodules collected 4 h after rewatering. This increase was observed in both cytoplasmic and bacteroid fractions. The possible physiological significance of these results is discussed.
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Claims 13
Claim · model-written summary
Drought inhibited soybean nodule nitrogenase activity by at least 90%.
- Taxon
- Soybean
Glycine maxt0 - Organ / stage
- Nodulest0
- Treatment
- drought stresse0
- Outcome
- Nitrogenase (C2H2 reducing) activitye0
- Direction
- inhibitede0
- Value
- 90% or moree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogenase (C2H2 reducing) activity was inhibited 90% or more as a result of drought stress.”
t0“Soybean Nodules”
Claim · model-written summary
Nitrogenase inhibition was substantially reversed after 4 h of recovery.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- inhibitione0
- Direction
- reversede0
- Qualifier
- after a 4 h recovery periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This inhibition was substantially reversed after a 4 h recovery period.”
t0“Soybean Nodules”
Claim · model-written summary
Drought raised pyrroline-5-carboxylate reductase activity by 55% in nodules of 25-day-old plants.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- nodulese0
- Treatment
- drought-stressede0
- Gene
- Pyrroline-5-carboxylate reductasee0
- Outcome
- Pyrroline-5-carboxylate reductase activitye0
- Direction
- highere0
- Value
- 55%e0
- Qualifier
- 25-d-old plantse0
- Comparator
- unstressed nodulese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pyrroline-5-carboxylate reductase activity in extracts of drought-stressed nodules from 25-d-old plants was 55% higher than in unstressed nodules”
t0“Soybean Nodules”
Claim · model-written summary
The same reductase activity in 55-day-old stressed plants was similar to controls.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- drought-stressede1
- Outcome
- Pyrroline-5-carboxylate reductase activitye1
- Direction
- similare0
- Qualifier
- 55-d-old plantse0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the same activity in preparations from 55-d-old plants was similar to that of control plants.”
e1“Pyrroline-5-carboxylate reductase activity in extracts of drought-stressed nodules”
t0“Soybean Nodules”
Claim · model-written summary
Reductase activities in recovering nodules of both ages were near controls.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- recovering nodulese0
- Outcome
- activitiese0
- Direction
- neare0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Extracts of recovering nodules on plants of both ages had activities near those of controls.”
t0“Soybean Nodules”
Claim · model-written summary
Drought raised pentose phosphate pathway activity about 65% in 55-day-old plant nodules.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Drought stresse0
- Outcome
- activity of the pentose phosphate pathwaye0
- Direction
- increasede0
- Value
- about 65%e0
- Qualifier
- 55-d-old plantse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress increased the activity of the pentose phosphate pathway by about 65% in extracts of nodules from 55-d-old plants”
t0“Soybean Nodules”
Claim · model-written summary
Drought did not affect pathway activity in 25-day-old plant nodules.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Drought stresse1
- Outcome
- activity of the pentose phosphate pathwaye1
- Direction
- no effecte0
- Qualifier
- younger plants (25-d-old)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no effect in extracts of nodules from younger plants (25-d-old).”
e1“Drought stress increased the activity of the pentose phosphate pathway”
t0“Soybean Nodules”
Claim · model-written summary
Bacteroid proline dehydrogenase activity was 3.7 times higher in stressed 25-day-old plant nodules than controls.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- stressed plantse0
- Gene
- Proline dehydrogenasee0
- Outcome
- Proline dehydrogenase activitye0
- Direction
- highere0
- Value
- 3.7e0
- Qualifier
- 25-e0
- Comparator
- comparable control bacteroidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proline dehydrogenase activity was 3.7 and 1.6 times higher in bacteroids isolated from nodules taken from 25- and 55-d-old stressed plants, respectively, than in comparable control bacteroids.”
t0“Soybean Nodules”
Claim · model-written summary
Bacteroid proline dehydrogenase activity was 1.6 times higher in stressed 55-day-old plant nodules than controls.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- stressed plantse0
- Gene
- Proline dehydrogenasee0
- Outcome
- Proline dehydrogenase activitye0
- Direction
- highere0
- Value
- 1.6e0
- Qualifier
- 55-d-olde0
- Comparator
- comparable control bacteroidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proline dehydrogenase activity was 3.7 and 1.6 times higher in bacteroids isolated from nodules taken from 25- and 55-d-old stressed plants, respectively, than in comparable control bacteroids.”
t0“Soybean Nodules”
Claim · model-written summary
Proline dehydrogenase activity remained high in bacteroids of recovering nodules at both ages.
- Taxon
- SoybeanGlycine maxt0
- Organ / stage
- recovering nodulese0
- Gene
- Proline dehydrogenasee1
- Outcome
- Proline dehydrogenase activitye1
- Direction
- remained highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This activity remained high in bacteroids from both sets of recovering nodules.”
e1“Proline dehydrogenase activity”
t0“Soybean Nodules”
Claim · model-written summary
Stressed nodules contained three to four times as much proline as unstressed nodules.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- stressed nodulese0
- Outcome
- amount of prolinee0
- Direction
- highere0
- Value
- 3- to 4-folde0
- Comparator
- unstressed nodulese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amount of proline in extracts from stressed nodules was 3- to 4-fold higher than in unstressed nodules”
t0“Soybean Nodules”
Claim · model-written summary
Nodule proline remained high four hours after rewatering.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- amount of prolinee1
- Direction
- remained highe0
- Qualifier
- 4 h after rewateringe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“remained high in nodules collected 4 h after rewatering.”
e1“The amount of proline in extracts from stressed nodules”
t0“Soybean Nodules”
Claim · model-written summary
The drought-related proline increase occurred in both cytoplasmic and bacteroid fractions.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- amount of prolinee1
- Direction
- increasee0
- Qualifier
- both cytoplasmic and bacteroid fractionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This increase was observed in both cytoplasmic and bacteroid fractions.”
e1“The amount of proline in extracts from stressed nodules”
t0“Soybean Nodules”
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