Abstract
Several research groups (both in South Africa and other countries) are currently involved in research aimed at improving symbiotic nitrogen fixation (SNF) and root nodule sustainability in soybean [Glycine max (L.) Merr.]. In many of these experiments potted plants are used, and in this paper the importance of careful selection of growth media is demonstrated. Bradyrhizobium japonicum-inoculated soybean seedlings were cultivated in pots containing N-free growth media (sand, fine vermiculite or coarse vermiculite) or a growth medium containing low concentrations of water-soluble nitrogen predominantly in the form of ammonium (mixture of potting soil, sand and vermiculite). The effects of growth media on shoot physiology were assessed by measurement of plastochron index, chlorophyll content and CO2 assimilation rates. Nodule numbers, nitrogenase activity and nodule ureide content were also determined. Although similar source–sink relationships were maintained in plants cultured in the various growth media, large effects on nodule numbers and SNF were observed. Shoot phenotype and physiology did not provide any insight into these belowground effects. The presence of mineral N, or sand as culture medium, led to the formation of more abundant nodules but with low SNF activity. Vermiculite, irrespective of particle size, resulted in plants with root systems housing nodules with high SNF activity. It is concluded that choice of growth media for cultivating soybean plants under controlled growth conditions is an important consideration, especially in multi-institution collaborations where comparability between experiments is a pre-requisite.
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Claims 8
Claim · model-written summary
Source–sink relationships were similar across growth media.
- Taxon
- soybean
Glycine maxt0 - Outcome
- source–sink relationshipse0
- Comparator
- various growth mediae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“similar source–sink relationships were maintained in plants cultured in the various growth media”
t0“soybean”
Claim · model-written summary
Shoot phenotype and physiology did not reveal the belowground responses.
- Taxon
- soybeanGlycine maxt0
- Outcome
- Shoot phenotype and physiology did not provide any insight into these belowground effectse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Shoot phenotype and physiology did not provide any insight into these belowground effects”
t0“soybean”
Claim · model-written summary
Mineral N produced more abundant soybean nodules with low fixation activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- mineral Ne0
- Outcome
- more abundant nodulese0
- Direction
- more abundante0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The presence of mineral N, or sand as culture medium, led to the formation of more abundant nodules but with low SNF activity”
t0“soybean”
Claim · model-written summary
Mineral N yielded low symbiotic nitrogen fixation activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- mineral Ne0
- Outcome
- SNF activitye0
- Direction
- lowe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The presence of mineral N, or sand as culture medium, led to the formation of more abundant nodules but with low SNF activity”
t0“soybean”
Claim · model-written summary
Sand medium produced more abundant nodules.
- Taxon
- soybeanGlycine maxt0
- Treatment
- sand as culture mediume0
- Outcome
- more abundant nodulese0
- Direction
- more abundante0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The presence of mineral N, or sand as culture medium, led to the formation of more abundant nodules but with low SNF activity”
t0“soybean”
Claim · model-written summary
Sand medium yielded low symbiotic nitrogen fixation activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- sand as culture mediume0
- Outcome
- SNF activitye0
- Direction
- lowe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The presence of mineral N, or sand as culture medium, led to the formation of more abundant nodules but with low SNF activity”
t0“soybean”
Claim · model-written summary
Vermiculite of either particle size yielded nodules with high fixation activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Vermiculitee0
- Outcome
- SNF activitye0
- Direction
- highe0
- Qualifier
- irrespective of particle sizee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Vermiculite, irrespective of particle size, resulted in plants with root systems housing nodules with high SNF activity”
t0“soybean”
Claim · model-written summary
Choice of growth medium is important for comparable controlled soybean studies.
- Taxon
- soybeanGlycine maxe0
- Outcome
- choice of growth media for cultivating soybean plants under controlled growth conditions is an important consideratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“choice of growth media for cultivating soybean plants under controlled growth conditions is an important consideration, especially in multi-institution collaborations where comparability between experiments is a pre-requisite”
The same questions in other papers
in vitro · symbiosis · Glycine max (soybean)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction · 1 reporting no difference from an alternative
- negative
- negative
- no effect
1 paper more in this group
See all 5 papers →growing medium · symbiosis · Glycine max (soybean)Positive and negative results
6 papers in the same direction as this paper · 2 reporting no difference from an alternative
- no effect
- no effect
- positive
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.