Abstract
Isolated roots of Phaseolus vulgaris were grown in aseptic culture using a modified Raggio technique in which the organic nutrients are fed to the cut (basal) end of the excised root while the root tip grows into a mineral-salt solution inoculated with Rhizobium. Treatments were applied to investigate the effects of varying the level of sucrose in the organic medium and of adding combined nitrogen as nitrate and urea to both media. There was a marked effect of sucrose on the growth and nodulation of the roots. Increasing the concentration increased the number of nodules both per root and per unit fresh weight of tissue. The growth of the roots was not affected by the level of combined nitrogen. Nitrate in the mineral-salt solution markedly reduced nodule numbers but in the agar medium it had only a slight delaying effect on nodulation. Urea in either the mineral-salt solution or the organic medium reduced nodule numbers though to a lesser extent than nitrate in the mineral-salt solution. The number of nodules formed was inversely correlated with the levels of soluble and inorganic nitrogen compounds in the tissues. It is suggested that the adverse effect of combined nitrogen on nodulation is due to the accumulation of unsequestered nitrogen compounds and a depletion of carbohydrates generally within the root tissues rather than the local effect of any particular nitrogen compound.
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Claims 6
Claim · model-written summary
Increasing sucrose concentration increased root nodule numbers per root and per fresh tissue weight.
- Taxon
- Phaseolus vulgaris
Phaseolus vulgarist0 - Treatment
- sucrosee1
- Outcome
- number of nodules both per root and per unit fresh weight of tissuee0
- Direction
- increasede0
RhizobiumNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing the concentration increased the number of nodules both per root and per unit fresh weight of tissue”
t0“Phaseolus vulgaris L.”
e1“Rhizobium. Treatments were applied to investigate the effects of varying the level of sucrose in the organic medium and of adding combined nitrogen as nitrate and urea”
Claim · model-written summary
Combined nitrogen level did not affect root growth.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- combined nitrogene0
- Outcome
- growth of the rootse0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The growth of the roots was not affected by the level of combined nitrogen”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Nitrate in mineral-salt solution markedly reduced nodule numbers.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- Nitrate in the mineral-salt solutione0
- Outcome
- nodule numberse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate in the mineral-salt solution markedly reduced nodule numbers”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Nitrate in agar medium only slightly delayed nodulation.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- Nitratee1
- Outcome
- nodulatione0
- Direction
- delayinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in the agar medium it had only a slight delaying effect on nodulation”
t0“Phaseolus vulgaris L.”
e1“Rhizobium. Treatments were applied to investigate the effects of varying the level of sucrose in the organic medium and of adding combined nitrogen as nitrate and urea”
Claim · model-written summary
Urea in either medium reduced nodule numbers less than nitrate in mineral-salt solution.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- Urea in either the mineral-salt solution or the organic mediume0
- Outcome
- nodule numberse0
- Direction
- reducede0
- Comparator
- nitrate in the mineral-salt solutione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Urea in either the mineral-salt solution or the organic medium reduced nodule numbers though to a lesser extent than nitrate in the mineral-salt solution”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Nodule number was inversely correlated with tissue soluble and inorganic nitrogen levels.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Compound
- soluble and inorganic nitrogen compoundse0
- Outcome
- number of nodules formede0
- Direction
- inversely correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number of nodules formed was inversely correlated with the levels of soluble and inorganic nitrogen compounds in the tissues”
t0“Phaseolus vulgaris L.”
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