Abstract
A nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots is presented. Plots consisted of 120 x 150 x 30 centimeter boxes containing 65 plants. The plants were grown in a medium grade sand under controlled nutrient, moisture, and root temperature conditions. Acetylene at a concentration of 10 milliliters per liter was circulated through manifolds in the chambers; equilibration required 5 minutes, and activity was linear with time. Optimum growth and assay environments resulted in activity of 70 micromoles ethylene per plant per hour. Plant development and yield were comparable to soil-grown companion plots.The well accepted hypothesis that developing seeds deprive the nodules of carbohydrate was not substantiated. The nondestructive acetylene reduction profile did not decline until 30 days after the onset of seed development (R-5). This result was consistent with reports from the literature which indicated that 60% of seasonal nitrogen was fixed after R-5. Further, a high correlation shown between integrated seasonal acetylene reduction and yield (r = 0.999) suggested a cooperative relationship between the roots and shoot. A reduction in source:sink ratio (60% defoliation) after R-5 had no effect on acetylene reduction. This showed that neither an increase in sink demand by the pods nor a carbon shortage during podfill decreased dinitrogen fixation. A conceptual model relating seed growth with carbon and nitrogen assimilation is proposed.
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Claims 7
Claim · model-written summary
The acetylene reduction assay needed 5 minutes of equilibration, and activity was linear with time.
- Taxon
- soybean
Glycine maxe0 - Outcome
- activitye1
- Value
- 5 minutese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e1“equilibration required 5 minutes, and activity was linear with time”
Claim · model-written summary
Optimum growth and assay environments gave acetylene reduction activity of 70 micromoles ethylene per plant per hour.
- Taxon
- soybeanGlycine maxe0
- Outcome
- activitye3
- Value
- 70 micromoles ethylene per plant per houre3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e3“Optimum growth and assay environments resulted in activity of 70 micromoles ethylene per plant per hour”
Claim · model-written summary
Soybean development and yield in sand-grown plants were comparable to soil-grown companion plots.
- Taxon
- soybeanGlycine maxe0
- Treatment
- medium grade sande2
- Outcome
- Plant development and yielde4
- Direction
- comparablee4
- Comparator
- soil-grown companion plotse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e2“The plants were grown in a medium grade sand under controlled nutrient, moisture, and root temperature conditions”
e4“Plant development and yield were comparable to soil-grown companion plots”
Claim · model-written summary
Yield rose with integrated seasonal acetylene reduction (r = 0.999), suggesting a cooperative root-shoot relationship.
- Taxon
- soybeanGlycine maxe0
- Organ / stage
- roots and shoote7
- Outcome
- yielde7
- Direction
- increaseinferrede7
- Value
- r = 0.999e7
- Qualifier
- integrated seasonal acetylene reductione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e7“a high correlation shown between integrated seasonal acetylene reduction and yield (r = 0.999) suggested a cooperative relationship between the roots and shoot”
Claim · model-written summary
Sixty percent defoliation after R-5 had no effect on acetylene reduction.
- Taxon
- soybeanGlycine maxe0
- Treatment
- 60% defoliatione7
- Outcome
- acetylene reductione7
- Direction
- no effecte7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e7“A reduction in source:sink ratio (60% defoliation) after R-5 had no effect on acetylene reduction”
Claim · model-written summary
The acetylene reduction profile did not decline until 30 days after onset of seed development (R-5).
- Taxon
- soybeanGlycine maxe0
- Organ / stage
- seed development (R-5)e5
- Outcome
- acetylene reduction profilee5
- Value
- 30 dayse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e5“The nondestructive acetylene reduction profile did not decline until 30 days after the onset of seed development (R-5)”
Claim · model-written summary
The hypothesis that developing seeds deprive nodules of carbohydrate was not substantiated.
- Taxon
- soybeanGlycine maxe0
- Outcome
- developing seeds deprive the nodules of carbohydratee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nondestructive acetylene reduction assay for nitrogenase activity of soybean (Glycine max L. Merr) field plots”
e6“The well accepted hypothesis that developing seeds deprive the nodules of carbohydrate was not substantiated”
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