Abstract
Abstract Research suggests that competition for photosynthate between nodules and seeds of soybeans [ Glycine max (L.) Merr.] may be responsible for the apparent decline in symbiotic nitrogen fixation during the high N requirement pod‐filling period. A study was conducted in eight highly productive commercial fields to characterize the development of nodules during the growing season and to determine the effect on nodulation of thinning to one plant/m 2 at a time (end of flowering period) when the response by the reproductive sink would be limited to a small increase in seed size. The number and size of nodules increased rapidly during flowering, peaked in early pod‐filling, and declined thereafter. After flowering, the percentage of red nodulated declined while the percentage of green (inactive) nodules increased. Total nodule volume/plant and active (i.e., red) nodule volume/plant peaked in mid‐August and then dropped off rapidly. The thinned plants showed significantly more nodule volume/plant, a greater percentage of red nodules, and a lower percentage of green nodules during pod‐filling, than did the plants growing at normal population densities. During that period, the thinned plants had 2 to 5 times as much active nodule volume/plant. The thinning treatment apparently postponed the decline in the nodules for several weeks. This effect was probably due to an increased supply of photosynthate available to the nodules at the lower plant density.
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Claims 10
Claim · model-written summary
Soybean nodule number and size rose during flowering, peaked in early pod filling, then declined.
- Taxon
- soybeans
Glycine maxe1 - Organ / stage
- nodulese0
- Outcome
- number and size of nodulese0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number and size of nodules increased rapidly during flowering, peaked in early pod‐filling, and declined thereafter.”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
After flowering, the percentage of red nodules declined.
- Taxon
- soybeansGlycine maxe1
- Outcome
- percentage of red nodulatede0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After flowering, the percentage of red nodulated declined”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
After flowering, the percentage of inactive green nodules increased.
- Taxon
- soybeansGlycine maxe1
- Outcome
- percentage of green (inactive) nodulese0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the percentage of green (inactive) nodules increased”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
Total and active nodule volumes per soybean plant peaked in mid August and then fell rapidly.
- Taxon
- soybeansGlycine maxe1
- Outcome
- Total nodule volume/plant and active (i.e., red) nodule volume/plante0
- Direction
- peakede0
- Qualifier
- mid‐Auguste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total nodule volume/plant and active (i.e., red) nodule volume/plant peaked in mid‐August and then dropped off rapidly.”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
Thinning significantly increased soybean nodule volume per plant during pod filling relative to normal density.
- Taxon
- soybeansGlycine maxe1
- Organ / stage
- pod‐fillinge0
- Treatment
- thinned plantse0
- Outcome
- nodule volume/plante0
- Direction
- moree0
- Comparator
- plants growing at normal population densitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The thinned plants showed significantly more nodule volume/plant, a greater percentage of red nodules, and a lower percentage of green nodules during pod‐filling, than did the plants growing at normal population densities.”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
Thinned soybean plants had a greater percentage of red nodules during pod filling than plants at normal density.
- Taxon
- soybeansGlycine maxe1
- Treatment
- thinned plantse0
- Outcome
- percentage of red nodulese0
- Direction
- greatere0
- Comparator
- plants growing at normal population densitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The thinned plants showed significantly more nodule volume/plant, a greater percentage of red nodules, and a lower percentage of green nodules during pod‐filling, than did the plants growing at normal population densities.”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
Thinned soybean plants had a lower percentage of green nodules during pod filling than plants at normal density.
- Taxon
- soybeansGlycine maxe1
- Treatment
- thinned plantse0
- Outcome
- percentage of green nodulese0
- Direction
- lowere0
- Comparator
- plants growing at normal population densitiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The thinned plants showed significantly more nodule volume/plant, a greater percentage of red nodules, and a lower percentage of green nodules during pod‐filling, than did the plants growing at normal population densities.”
e1“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
Thinned plants had 2 to 5 times as much active nodule volume per plant during pod filling.
- Taxon
- soybeansGlycine maxe2
- Treatment
- thinned plantse0
- Outcome
- active nodule volume/plante0
- Direction
- as muche0
- Value
- 2 to 5 timese0
- Comparator
- plants growing at normal population densitiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During that period, the thinned plants had 2 to 5 times as much active nodule volume/plant.”
e1“plants growing at normal population densities”
e2“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
Thinning apparently postponed soybean nodule decline for several weeks.
- Taxon
- soybeansGlycine maxe2
- Treatment
- thinning treatmente0
- Outcome
- decline in the nodulese0
- Direction
- postponede0
- Value
- several weekse0
- Comparator
- plants growing at normal population densitiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The thinning treatment apparently postponed the decline in the nodules for several weeks.”
e1“plants growing at normal population densities”
e2“soybeans [ Glycine max (L.) Merr.]”
Claim · model-written summary
The authors attributed delayed nodule decline at lower plant density to more photosynthate available to nodules.
- Taxon
- soybeansGlycine maxe1
- Outcome
- increased supply of photosynthate available to the nodulese0
- Qualifier
- lower plant densitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This effect was probably due to an increased supply of photosynthate available to the nodules at the lower plant density.”
e1“soybeans [ Glycine max (L.) Merr.]”
The same questions in other papers
pruning · symbiosis · Glycine max (soybean)Positive and negative results
2 papers in the same direction as this paper · 6 in the opposite direction
- negative
- no effect
- negative
5 papers more in this group
See all 9 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.