Paper · 2026 · Journal of Forest Research

Estimation of the soil depth at which 137 Cs is taken up by roots of Eleutherococcus sciadophylloides (koshiabura), an edible wild tree species

Masami Kanao Koshikawa; Mirai Watanabe; Masanori Tamaoki; et al.

5
claims
9
verbatim quotes
2
citations
4
research areas
✓
Open access

Abstract

Eleutherococcus sciadophylloides (commonly known as koshiabura) is a deciduous tree whose young buds are a popular wild food in Japan. After the 2011 Fukushima nuclear accident, radiocaesium contamination occurred in edible wild plants in forests, with particularly high levels in E. sciadophylloides buds. Consequently, restrictions on their consumption have impacted local cuisine and cultural traditions. To investigate the mechanisms underlying these high 137Cs concentrations, we employed a multifaceted approach combining root excavation, environmental DNA (eDNA) analysis, and Sr and Cs isotope analyses to cross-validate root depth and uptake dynamics. Root excavation revealed predominantly shallow root systems. eDNA analysis confirmed that the lateral roots collected from soil cores were most abundant within the 0–5 cm layer of the mineral soil horizon. Sr isotope analysis indicated that small E. sciadophylloides trees primarily absorbed cations from this layer. In contrast, Cs isotope analysis was insufficient to determine the soil depth of 137Cs uptake. This discrepancy may reflect contributions from both the root uptake of 137Cs leached from the organic horizon and the supply of 137Cs to buds through internal translocation within the tree. Our findings indicate that small E. sciadophylloides trees rely primarily on shallow root systems for nutrient uptake, specifically from the 0–5 cm soil layer where 137Cs has accumulated. This characteristic likely contributes to the high 137Cs levels observed in E. sciadophylloides buds. Further research is needed to clarify the relative contributions of root uptake and internal translocation to 137Cs transfer into buds.

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Claims 5

Observationobservedoriginal resultmeasured

Claim · model-written summary

Root excavation found predominantly shallow root systems.

Taxon
Eleutherococcus sciadophylloidesChengiopanax sciadophylloidese0
Outcome
predominantly shallow root systemse1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Chengiopanax sciadophylloides
Chengiopanax sciadophylloides · TaxonKENPEI · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“Eleutherococcus sciadophylloides (commonly known as koshiabura) is a deciduous tree”

✓ located verbatim in the source · abstract, characters 0–83 · show in text ↑
e1

“Root excavation revealed predominantly shallow root systems”

✓ located verbatim in the source · abstract, characters 661–720 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Lateral roots collected from soil cores were most abundant in the 0–5 cm mineral soil layer.

Taxon
E. sciadophylloidesChengiopanax sciadophylloidese0
Organ / stage
lateral rootse1
Outcome
most abundante1
Direction
most abundante1
Value
0–5 cme1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Chengiopanax sciadophylloides
Chengiopanax sciadophylloides · TaxonKENPEI · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“high levels in E. sciadophylloides buds”

✓ located verbatim in the source · abstract, characters 266–305 · show in text ↑
e1

“the lateral roots collected from soil cores were most abundant within the 0–5 cm layer of the mineral soil horizon”

✓ located verbatim in the source · abstract, characters 751–865 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Small E. sciadophylloides trees primarily absorbed cations from the 0–5 cm mineral soil layer.

Taxon
E. sciadophylloidesChengiopanax sciadophylloidese0
Outcome
absorbed cationse0
Value
0–5 cme0
Qualifier
smalle0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Chengiopanax sciadophylloides
Chengiopanax sciadophylloides · TaxonKENPEI · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“eDNA analysis confirmed that the lateral roots collected from soil cores were most abundant within the 0–5 cm layer of the mineral soil horizon. Sr isotope analysis indicated that small E. sciadophylloides trees primarily absorbed cations from this layer”

✓ located verbatim in the source · abstract, characters 722–976 · show in text ↑
Method / resourceobservedoriginal resultmeasured

Claim · model-written summary

Cs isotope analysis could not establish the soil depth of 137Cs uptake.

Taxon
E. sciadophylloidesChengiopanax sciadophylloidese0
Outcome
insufficient to determine the soil depth of 137Cs uptakee1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Chengiopanax sciadophylloides
Chengiopanax sciadophylloides · TaxonKENPEI · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“high levels in E. sciadophylloides buds”

✓ located verbatim in the source · abstract, characters 266–305 · show in text ↑
e1

“Cs isotope analysis was insufficient to determine the soil depth of 137Cs uptake”

✓ located verbatim in the source · abstract, characters 991–1071 · show in text ↑
Mechanismauthor interpretationoriginal resultmeasured

Claim · model-written summary

The authors infer that uptake from shallow soil may contribute to high 137Cs in buds.

Taxon
E. sciadophylloidesChengiopanax sciadophylloidese1
Outcome
high 137Cs levels observed in E. sciadophylloides budse1
Qualifier
likely contributese1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Chengiopanax sciadophylloides
Chengiopanax sciadophylloides · TaxonKENPEI · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“high levels in E. sciadophylloides buds”

✓ located verbatim in the source · abstract, characters 266–305 · show in text ↑
e1

“This characteristic likely contributes to the high 137Cs levels observed in E. sciadophylloides buds”

✓ located verbatim in the source · abstract, characters 1452–1552 · show in text ↑