Abstract
In the field, plant root development is of primary importance under P deficient conditions. Two sand culture experiments were conducted to examine the effects of P stress, nodulation, and N source on the growth, dry matter distribution, and root development of ‘Clark 63’ soybean ( Glycine max L. Merr.). In both experiments two levels of N (0 and 5.0 mM N) were employed: plants were either solely dependent upon symbiotic N fixation (N‐fixing), or primarily dependent upon uptake of combined N from the nutrient solution (N supplied). Nodule dry weight of N‐fixing plants grown at the highest P level (2.0 µ/ml) comprised 9% of total plant dry weight and 61% of root dry weight of 35‐day‐old soybeans. A decrease in the P supply inhibited nodule growth relatively more than either root or shoot growth. For N‐supplied soybean, a decrease in the P supply affected shoot growth relatively more than either nodule or root growth. When grown at intermediate P levels (0.02 to 0.5 µ/ml), the root + nodule:total plant dry weight ratio was similar in both N‐fixing and N‐supplied plants. However, the rootttotal plant dry weight ratio of N‐fixing plants was was less than that of N‐supplied plants at all P levels. There was an inverse relationship between nodule mass and total root length although the number of first‐order lateral roots on nodulated and nonnodulated plants was the same. The data suggest that two functional equilibria operate in the N‐fixing plant, namely, the partitioning of dry matter between (i) the underground portion of the plant and the shoot and (ii) the root and nodules. Phosphorus stress affected the root‐nodule equilibrium relatively more than the partitioning of dry matter between below‐ground and above‐ground parts of the plant.
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Claims 10
Claim · model-written summary
At the highest P level, nodules made up 9% of total dry weight in N-fixing soybean.
- Taxon
- soybeans
Glycine maxe0 - Material
- ‘Clark 63’e1
- Organ / stage
- Nodulee0
- Treatment
- highest P level (2.0 µ/ml)e0
- Outcome
- total plant dry weighte0
- Value
- 9%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nodule dry weight of N‐fixing plants grown at the highest P level (2.0 µ/ml) comprised 9% of total plant dry weight and 61% of root dry weight of 35‐day‐old soybeans”
t0“Soybean”
e1“root development of ‘Clark 63’ soybean ( Glycine max L. Merr.)”
Claim · model-written summary
At the highest P level, nodules made up 61% of root dry weight in N-fixing soybean.
- Taxon
- soybeansGlycine maxe0
- Treatment
- highest P level (2.0 µ/ml)e0
- Outcome
- root dry weighte0
- Value
- 61%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nodule dry weight of N‐fixing plants grown at the highest P level (2.0 µ/ml) comprised 9% of total plant dry weight and 61% of root dry weight of 35‐day‐old soybeans”
Claim · model-written summary
Reduced P supply inhibited nodule growth more than root or shoot growth.
- Taxon
- soybeanGlycine maxt0
- Treatment
- decrease in the P supplye0
- Outcome
- nodule growthe0
- Direction
- inhibitede0
- Comparator
- root or shoot growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A decrease in the P supply inhibited nodule growth relatively more than either root or shoot growth”
t0“Soybean”
Claim · model-written summary
Under supplied N, reduced P affected shoot growth more than nodule or root growth.
- Taxon
- soybeanGlycine maxe0
- Treatment
- decrease in the P supplye0
- Outcome
- shoot growthe0
- Comparator
- nodule or root growthe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For N‐supplied soybean, a decrease in the P supply affected shoot growth relatively more than either nodule or root growth”
Claim · model-written summary
At intermediate P levels, the root plus nodule share of total plant dry weight was similar for N-fixing and N-supplied plants.
- Taxon
- soybeanGlycine maxt0
- Treatment
- intermediate P levels (0.02 to 0.5 µ/ml)e0
- Outcome
- root + nodule:total plant dry weight ratioe0
- Direction
- similare0
- Comparator
- N‐supplied plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When grown at intermediate P levels (0.02 to 0.5 µ/ml), the root + nodule:total plant dry weight ratio was similar in both N‐fixing and N‐supplied plants”
t0“Soybean”
Claim · model-written summary
The root share of plant dry weight was lower in N-fixing than N-supplied plants at all P levels.
- Taxon
- soybeanGlycine maxt0
- Outcome
- rootttotal plant dry weight ratioe0
- Direction
- less thane0
- Qualifier
- at all P levelse0
- Comparator
- N‐supplied plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the rootttotal plant dry weight ratio of N‐fixing plants was was less than that of N‐supplied plants at all P levels”
t0“Soybean”
Claim · model-written summary
Nodule mass and total root length had an inverse relationship.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- nodulee0
- Outcome
- total root lengthe0
- Direction
- inversee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was an inverse relationship between nodule mass and total root length”
t0“Soybean”
Claim · model-written summary
First-order lateral root numbers were equal in nodulated and nonnodulated plants.
- Taxon
- soybeanGlycine maxt0
- Outcome
- number of first‐order lateral rootse0
- Direction
- the samee0
- Comparator
- nonnodulated plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the number of first‐order lateral roots on nodulated and nonnodulated plants was the same”
t0“Soybean”
Claim · model-written summary
The authors infer two dry matter partitioning equilibria in N-fixing soybean.
- Taxon
- soybeanGlycine maxt0
- Organ / stage
- root and nodulese0
- Outcome
- partitioning of dry mattere0
- Qualifier
- two functional equilibriae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The data suggest that two functional equilibria operate in the N‐fixing plant, namely, the partitioning of dry matter between (i) the underground portion of the plant and the shoot and (ii) the root and nodules”
t0“Soybean”
Claim · model-written summary
P stress affected root-nodule balance more than aboveground-belowground partitioning.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Phosphorus stresse0
- Outcome
- root‐nodule equilibriume0
- Comparator
- partitioning of dry matter between below‐ground and above‐ground parts of the plante0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phosphorus stress affected the root‐nodule equilibrium relatively more than the partitioning of dry matter between below‐ground and above‐ground parts of the plant”
t0“Soybean”
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See all 146 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.