Abstract
SUMMARY Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter. These effects were accompanied by a major shift in the population balance from a predominantly Gram‐positive, chromogenic type of microflora to one dominated by Gram‐negative and non‐chromogenic organisms. Fluorescent pseudomonads became particularly numerous in the urea‐treated leaves and many were found to suppress the development in vitro of Venturia inaequalis. An organism forming yellow colonies, possessing exceptional activity against the scab fungus, which was also found in urea‐treated leaves, was shown to be a Gram‐negative, peritrichous bacterium. No antagonistic organisms were isolated from untreated control leaves, but many were found–usually chromogenic forms–which appeared to stimulate the scab fungus in vitro. Treatment with urea accelerated the decomposition of the leaves and suppressed the development of V. inaequalis in the portions of the laminae which remained structurally intact until the following spring. Many of the effects of urea were enhanced by the addition of glucose, streptomycin, or a suspension of a Pseudomonas sp. isolated from leaves during the winter. Streptomycin alone reduced the total numbers of microorganisms in the leaves but increased the proportion of Gram‐negative organisms: this was associated with diminished ascospore production in the spring. There was no direct evidence that the antagonistic flora stimulated by urea was responsible for the inhibition of V. inaequalis , and alternative explanations are suggested.
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Claims 15
Claim · model-written summary
Urea treatment of apple leaves increased the microbial populations during winter.
- Taxon
- apple
Malus domesticae0 - Treatment
- ureae0
- Outcome
- microbial populationse0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
Claim · model-written summary
Urea shifted the leaf population balance from Gram‐positive chromogenic microflora to Gram‐negative and non‐chromogenic organisms.
- Taxon
- appleMalus domesticae0
- Outcome
- population balancee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e1“These effects were accompanied by a major shift in the population balance from a predominantly Gram‐positive, chromogenic type of microflora to one dominated by Gram‐negative and non‐chromogenic organisms”
Claim · model-written summary
Fluorescent pseudomonads became numerous in urea-treated leaves.
- Taxon
- appleMalus domesticae0
- Treatment
- ureae0
- Outcome
- Fluorescent pseudomonadse2
- Direction
- increaseinferrede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e2“Fluorescent pseudomonads became particularly numerous”
Claim · model-written summary
Many fluorescent pseudomonads suppressed the in vitro development of Venturia inaequalis.
- Taxon
- appleMalus domesticae0
- Interactor
- Venturia inaequalis
Venturia inaequalise3pathogen - Second interactor
- Fluorescent pseudomonadsPseudomonas fluorescens groupe2biocontrol_agent
- Outcome
- development in vitro of Venturia inaequalise3
- Direction
- suppresse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e2“Fluorescent pseudomonads became particularly numerous”
e3“many were found to suppress the development in vitro of Venturia inaequalis”
Claim · model-written summary
An organism forming yellow colonies had exceptional activity against the scab fungus.
- Taxon
- appleMalus domesticae0
- Interactor
- scab funguse4pathogen
- Second interactor
- An organism forming yellow coloniese5biocontrol_agent
- Outcome
- exceptional activity against the scab funguse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e4“possessing exceptional activity against the scab fungus”
e5“An organism forming yellow colonies”
Claim · model-written summary
The yellow-colony organism is a Gram‐negative, peritrichous bacterium.
- Taxon
- appleMalus domesticae0
- Outcome
- Gram‐negative, peritrichous bacteriume1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e1“Gram‐negative, peritrichous bacterium”
Claim · model-written summary
No antagonistic organisms were isolated from untreated control leaves.
- Taxon
- appleMalus domesticae0
- Outcome
- antagonistic organismse5
- Comparator
- untreated control leavese5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e5“No antagonistic organisms were isolated from untreated control leaves”
Claim · model-written summary
Many organisms from urea-treated leaves appeared to stimulate the scab fungus in vitro.
- Taxon
- appleMalus domesticae0
- Interactor
- scab funguse1pathogen
- Outcome
- stimulate the scab fungus in vitroe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e1“which appeared to stimulate the scab fungus in vitro”
Claim · model-written summary
Urea accelerated the decomposition of apple leaves.
- Taxon
- appleMalus domesticae0
- Treatment
- ureae6
- Outcome
- decomposition of the leavese6
- Direction
- acceleratede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e6“Treatment with urea accelerated the decomposition of the leaves”
Claim · model-written summary
Urea suppressed the development of V. inaequalis in leaf portions that stayed intact until spring.
- Taxon
- appleMalus domesticae0
- Treatment
- ureae0
- Interactor
- V. inaequalisVenturia inaequalise7pathogen
- Outcome
- development of V. inaequalise7
- Direction
- suppressede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e7“suppressed the development of V. inaequalis in the portions of the laminae which remained structurally intact until the following spring”
Claim · model-written summary
Glucose, streptomycin or a Pseudomonas suspension enhanced the effects of urea.
- Taxon
- appleMalus domesticae0
- Treatment
- addition of glucose, streptomycin, or a suspension of a Pseudomonas sp.e6
- Outcome
- effects of ureae6
- Direction
- enhancede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e6“Many of the effects of urea were enhanced by the addition of glucose, streptomycin, or a suspension of a Pseudomonas sp.”
Claim · model-written summary
Streptomycin alone reduced the total number of leaf microorganisms.
- Taxon
- appleMalus domesticae0
- Treatment
- Streptomycine1
- Outcome
- total numbers of microorganismse1
- Direction
- reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e1“Streptomycin alone reduced the total numbers of microorganisms in the leaves”
Claim · model-written summary
Streptomycin increased the proportion of Gram‐negative organisms.
- Taxon
- appleMalus domesticae0
- Treatment
- Streptomycine1
- Outcome
- proportion of Gram‐negative organismse2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e1“Streptomycin alone reduced the total numbers of microorganisms in the leaves”
e2“but increased the proportion of Gram‐negative organisms”
Claim · model-written summary
Streptomycin was associated with diminished ascospore production in spring.
- Taxon
- appleMalus domesticae0
- Treatment
- Streptomycine1
- Outcome
- ascospore productione3
- Direction
- diminishede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e1“Streptomycin alone reduced the total numbers of microorganisms in the leaves”
e3“this was associated with diminished ascospore production in the spring”
Claim · model-written summary
There was no direct evidence that the urea-stimulated antagonistic flora caused the inhibition of V. inaequalis.
- Taxon
- appleMalus domesticae0
- Outcome
- inhibition of V. inaequalise4
- Qualifier
- no direct evidencee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of detached apple leaves in October with urea induced a rapid and prolonged increase in the microbial populations present in the leaves during the winter”
e4“There was no direct evidence that the antagonistic flora stimulated by urea was responsible for the inhibition of V. inaequalis”
The same questions in other papers
nitrogen · Venturia inaequalis · Malus domestica (apple)Positive and negative results
10 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
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9 papers more in this group
See all 13 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.