Abstract
Abstract Annual weed seeds persist in cultivated soils due to seed dormancy and possibly to resistance to microbial attack. The relationships between microorganisms and velvetleaf ( Abutilon theophrasti Medic.) seeds were investigated to elucidate the deterioration resistance mechanisms in this species. Microorganisms were isolated from velvetleaf seeds matured on the plant and from seeds dispersed on the soil surface. An association of sporulating fungi comprised of Alternaria alternata, Cladosporium cladosporioides, Epicoccum purpurascens , and Fusarium spp. was consistently found on the seed surface. This association persisted on seeds after dispersal to the soil. Seed deterioration was infrequent despite abundant microbial growth on the seed surface. About 80% of the bacteria isolated from within seeds were antagonistic to externally seedborne fungi. The proportion of surface‐sterilized seeds with internal fungi was 10%, indicating the seed coat acts as a barrier to most fungal invasions. When the seed coat was punctured, however, seed deterioration by the seedborne microorganisms readily occurred. Seed coat extracts contained tannin‐like compounds that inhibited in vitro growth of several bacterial and fungal isolates. Histochemical examination of seed sections revealed localization of tannin‐like compounds in the palisade layer of the seed coat and the chalazal area of the embryo. It is suggested that deterioration of velvetleaf seeds by microorganisms is limited by the dense layer of palisade cells in the seed coat, chemical compounds within the seed coat that are inhibitory to certain microorganisms outside the seed, and antagonistic bacteria located within the seed. Resistances to microbial attack may act together with seed dormancy to maintain velvetleaf seed longevity in soil.
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Claims 9
Claim · model-written summary
A sporulating fungal association consistently occurred on velvetleaf seed surfaces.
- Taxon
- velvetleaf
Abutilon theophrastit0 - Interactor
- Alternaria alternata
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Alternaria alternatae0other - Outcome
- seed surfacee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“An association of sporulating fungi comprised of Alternaria alternata, Cladosporium cladosporioides, Epicoccum purpurascens , and Fusarium spp. was consistently found on the seed surface.”
t0“Velvetleaf Seed”
Claim · model-written summary
The fungal association persisted after seed dispersal.
Not reportedTaxon
Verbatim
e0“This association persisted on seeds after dispersal to the soil.”
Claim · model-written summary
Seed deterioration was infrequent despite abundant surface microbial growth.
Not reportedTaxon
Verbatim
e0“Seed deterioration was infrequent despite abundant microbial growth on the seed surface.”
Claim · model-written summary
About 80% of internal bacterial isolates antagonized external seedborne fungi.
Not reportedTaxon
Verbatim
e0“About 80% of the bacteria isolated from within seeds were antagonistic to externally seedborne fungi.”
Claim · model-written summary
Internal fungi occurred in 10% of surface-sterilized seeds.
Not reportedTaxon
Verbatim
e0“The proportion of surface‐sterilized seeds with internal fungi was 10%”
Claim · model-written summary
Puncturing the coat permitted microbial seed deterioration.
Not reportedTaxonComparatorDirection
Verbatim
e0“When the seed coat was punctured, however, seed deterioration by the seedborne microorganisms readily occurred.”
Claim · model-written summary
Seed-coat extracts inhibited growth of bacterial and fungal isolates.
- Treatment
- Seed coat extractse0
- Compound
- tannin‐like compoundse0
- Outcome
- growth of several bacterial and fungal isolatese0
- Direction
- inhibitede0
- Setting
- in vitroe0
Not reportedTaxonComparator
Verbatim
e0“Seed coat extracts contained tannin‐like compounds that inhibited in vitro growth of several bacterial and fungal isolates.”
Claim · model-written summary
Tannin-like compounds localized in the palisade layer and embryo chalaza.
- Organ / stage
- palisade layer of the seed coat and the chalazal area of the embryoe0
- Outcome
- localization of tannin‐like compoundse0
Not reportedTaxon
Verbatim
e0“Histochemical examination of seed sections revealed localization of tannin‐like compounds in the palisade layer of the seed coat and the chalazal area of the embryo.”
Claim · model-written summary
Seed-coat structure, inhibitory compounds and internal bacteria were proposed to limit microbial deterioration.
- Taxon
- velvetleafAbutilon theophrastie0
- Outcome
- deterioration of velvetleaf seedse0
- Qualifier
- dense layer of palisade cells in the seed coate0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It is suggested that deterioration of velvetleaf seeds by microorganisms is limited by the dense layer of palisade cells in the seed coat, chemical compounds within the seed coat that are inhibitory to certain microorganisms outside the seed, and antagonistic bacteria located within the seed.”
The same questions in other papers
botanical · growth · Abutilon theophrasti (velvetleaf)Positive and negative results
4 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- negative
- positive
3 papers more in this group
See all 7 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.