Abstract
A hexaploid line of Caucasian clover (Trifolium ambiguum), inoculated with two strains of Rhizobium trifolii, was grown in tubes of nitrogen-free medium under bacteriologically-controlled conditions. Observations were made on various symbiotic characteristics of the seedlings. After 30 days, they were transplanted into pots of sand and vermiculite watered with nutrient solution lacking nitrogen and grown for another 100 days. Uninoculated plants supplied with various levels of combined nitrogen were used for comparison. R, trifolii strain CC283b was classified as highly effective and was greatly superior in nitrogen-fixing ability to strain CC231a which had been used routinely in Australia for many years for inoculation of experimental sowings of Caucasian clover. In this line of T, ambiguum, the inherent plant-to-plant variation was accentuated in plants relying on symbiotically-fixed nitrogen. This effect was strong in plants inoculated with the intermediately-effective strain CC231 a but mild in plants inoculated with the highly-effective strain CC2836, i.e., a larger component of the variability amongst CC231a plants was due to the symbiosis than was the case for CC283b plants. Seedlings inoculated with the intermediately-effective strain and selected on the basis of within-tube characteristics such as time to initial nodulation, symbiotic effectiveness rating, and nodule size produced more dry matter when grown in pots than the unselected population and were as productive as plants inoculated with the highly-effective strain. In contrast, with the highly-effective strain, selected plants grown in pots produced very little more dry matter than the unselected population. It was concluded that the use of within-tube symbiotic characteristics as a means of selection for improved production will only be successful when a substantial component of the plant-to-plant variability is due to the symbiosis.
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Claims 7
Claim · model-written summary
R. trifolii CC283b was highly effective and fixed more nitrogen than CC231a.
- Taxon
- Trifolium ambiguum
Trifolium ambiguumt0 - Interactor
- R, trifolii strain CC283be0symbiont
- Outcome
- nitrogen-fixing abilitye0
- Direction
- greatly superiore0
- Comparator
- strain CC231ae0
Not reportedMaterial
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“R, trifolii strain CC283b was classified as highly effective and was greatly superior in nitrogen-fixing ability to strain CC231a”
Claim · model-written summary
Symbiotic nitrogen reliance accentuated plant-to-plant variation in the hexaploid line.
- Taxon
- Trifolium ambiguumTrifolium ambiguumt0
- Material
- this line of T, ambiguume0
- Outcome
- plant-to-plant variatione0
- Direction
- accentuatede0
- Qualifier
- relying on symbiotically-fixed nitrogene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“In this line of T, ambiguum, the inherent plant-to-plant variation was accentuated in plants relying on symbiotically-fixed nitrogen.”
Claim · model-written summary
Plant variability attributable to symbiosis was stronger with CC231a than with CC283b.
- Taxon
- Trifolium ambiguumTrifolium ambiguumt0
- Interactor
- CC231ae0symbiont
- Outcome
- component of the variabilitye0
- Direction
- largere0
- Comparator
- CC283b plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“This effect was strong in plants inoculated with the intermediately-effective strain CC231 a but mild in plants inoculated with the highly-effective strain CC2836, i.e., a larger component of the variability amongst CC231a plants was due to the symbiosis than was the case for CC283b plants.”
Claim · model-written summary
Selecting seedlings inoculated with the intermediately effective strain using within-tube traits increased later pot dry matter over unselected plants.
- Taxon
- Trifolium ambiguumTrifolium ambiguumt0
- Treatment
- selected on the basis of within-tube characteristicse0
- Outcome
- dry mattere0
- Direction
- moree0
- Comparator
- the unselected populatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“Seedlings inoculated with the intermediately-effective strain and selected on the basis of within-tube characteristics such as time to initial nodulation, symbiotic effectiveness rating, and nodule size produced more dry matter when grown in pots than the unselected population”
Claim · model-written summary
Selected seedlings inoculated with the intermediately effective strain were as productive as those inoculated with the highly effective strain.
- Taxon
- Trifolium ambiguumTrifolium ambiguumt0
- Outcome
- productivee0
- Direction
- as productive ase0
- Comparator
- plants inoculated with the highly-effective straine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“were as productive as plants inoculated with the highly-effective strain.”
Claim · model-written summary
Under the highly effective strain, selection yielded very little extra pot dry matter relative to unselected plants.
- Taxon
- Trifolium ambiguumTrifolium ambiguumt0
- Treatment
- selected plantse0
- Outcome
- dry mattere0
- Direction
- very little moree0
- Comparator
- the unselected populatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“with the highly-effective strain, selected plants grown in pots produced very little more dry matter than the unselected population.”
Claim · model-written summary
The authors concluded within-tube symbiotic selection succeeds only when symbiosis accounts for substantial plant variation.
- Taxon
- Trifolium ambiguumTrifolium ambiguumt0
- Outcome
- use of within-tube symbiotic characteristics as a means of selection for improved productione0
- Qualifier
- when a substantial component of the plant-to-plant variability is due to the symbiosise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Trifolium ambiguum”
e0“the use of within-tube symbiotic characteristics as a means of selection for improved production will only be successful when a substantial component of the plant-to-plant variability is due to the symbiosis.”