Abstract
Dramatic differences in the height of lima beans (Phaseolus lunatus L.) treated with two different Rhizobium strains were studied. Lima beans were grown in Perlite in the greenhouse or in a minus-N culture solution in the growth chamber. The plants were inoculated with either Rhizobium sp. (lima bean) strain 127E15, which contains the constitutive nitrate reductase activity, or strain 127E14, which lacks that activity. For up to 3 weeks, no growth differences were observed in the plants inoculated with either strain. Five weeks after inoculation, however, those plants inoculated with strain 127E14 were significantly taller and had a larger number of leaves than those inoculated with strain 127E15. The difference in plant height was the result of increased internode elongation caused by inoculation with Rhizobium sp. 127E14. This response was observed with all lima bean cultivars tested, including Henderson, Fordhook, Allgreen, and Early Thorogreen. The growth difference occurred in plants cultured in the greenhouse or in the growth chamber.No differences were observed in fresh weights of nodules, roots, axes, leaves, or flowers. The number of nodules, pods, or flowers also did not differ. Acetylene reduction rates and total N content were equal in plants inoculated with strains 127E14 or 127E15.Inasmuch as only internode length and leaf number differed between Rhizobium treatments, the response appeared to be hormone-mediated. Application of gibberellic acid to the apex of plants inoculated with strain 127E15 caused an increase in plant height similar to that observed in untreated plants inoculated with strain 127E14. Conversely, the height of plants infected with strain 127E14 was decreased by application of gibberellin synthesis inhibitors to the root system. These data suggest that the increased growth caused by inoculation with strain 127E14 could be the result of increased gibberellin synthesis in lima bean nodules infected with that strain. Whether this response was related to the absence of nitrate reductase activity in strain 127E14 is unknown.
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Claims 10
Claim · model-written summary
Growth did not differ between strain treatments for up to three weeks.
Verbatim
e0“For up to 3 weeks, no growth differences were observed in the plants inoculated with either strain”
Claim · model-written summary
At five weeks 127E14 inoculation produced taller plants than 127E15.
Verbatim
e0“Five weeks after inoculation, however, those plants inoculated with strain 127E14 were significantly taller and had a larger number of leaves than those inoculated with strain 127E15”
Claim · model-written summary
At five weeks 127E14 inoculation produced more leaves than 127E15.
Verbatim
e0“Five weeks after inoculation, however, those plants inoculated with strain 127E14 were significantly taller and had a larger number of leaves than those inoculated with strain 127E15”
Claim · model-written summary
Greater plant height resulted from increased internode elongation under 127E14 inoculation.
- Taxon
- lima bean
Phaseolus lunatust0 - Interactor
- Rhizobium sp. 127E14e0symbiont
- Outcome
- plant heighte0
- Qualifier
- increased internode elongatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The difference in plant height was the result of increased internode elongation caused by inoculation with Rhizobium sp. 127E14”
t0“lima beans (Phaseolus lunatus L.)”
Claim · model-written summary
Fresh weights of nodules, roots, axes, leaves and flowers did not differ between strain treatments.
- Taxon
- lima beanPhaseolus lunatust0
- Treatment
- Rhizobium treatmentse1
- Outcome
- fresh weights of nodules, roots, axes, leaves, or flowerse0
- Direction
- No differencese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No differences were observed in fresh weights of nodules, roots, axes, leaves, or flowers”
t0“lima beans (Phaseolus lunatus L.)”
e1“between Rhizobium treatments”
Claim · model-written summary
Nodule, pod and flower numbers did not differ between strain treatments.
- Taxon
- lima beanPhaseolus lunatust0
- Treatment
- Rhizobium treatmentse1
- Outcome
- number of nodules, pods, or flowerse0
- Direction
- did not differe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number of nodules, pods, or flowers also did not differ”
t0“lima beans (Phaseolus lunatus L.)”
e1“between Rhizobium treatments”
Claim · model-written summary
Acetylene reduction rates and total N content were equal under both strains.
Verbatim
e0“Acetylene reduction rates and total N content were equal in plants inoculated with strains 127E14 or 127E15”
Claim · model-written summary
Gibberellic acid applied to 127E15 plants increased height similarly to untreated 127E14 plants.
Verbatim
e0“Application of gibberellic acid to the apex of plants inoculated with strain 127E15 caused an increase in plant height similar to that observed in untreated plants inoculated with strain 127E14”
Claim · model-written summary
Gibberellin synthesis inhibitors reduced height of plants inoculated with 127E14.
- Taxon
- plantsViridiplantaee0
- Treatment
- gibberellin synthesis inhibitorse0
- Interactor
- strain 127E14e0symbiont
- Outcome
- heighte0
- Direction
- decreasede0
Not reportedComparator
Verbatim
e0“height of plants infected with strain 127E14 was decreased by application of gibberellin synthesis inhibitors to the root system”
Claim · model-written summary
The authors suggest increased gibberellin synthesis in nodules could explain 127E14 induced growth.
- Taxon
- lima beanPhaseolus lunatuse0
- Interactor
- strain 127E14e0symbiont
- Outcome
- increased growthe0
- Qualifier
- increased gibberellin synthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased growth caused by inoculation with strain 127E14 could be the result of increased gibberellin synthesis in lima bean nodules”
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