Li et al. 2025 - Funneliformis mosseae and copper effects on Astragalus cadmium uptake

Li and colleagues tested whether arbuscular mycorrhizal fungus inoculation, copper addition, or both could improve growth and alter cadmium distribution in Astragalus sinicus under Cd-stressed pot conditions. This is primary phytoremediation and agronomic-mitigation evidence, not food occurrence evidence. A. sinicus is treated in this paper as a green-manure/phytoremediation plant; the study does not measure a consumer food, ingredient, feed, cosmetic, or branded product.

The main finding is that F. mosseae and Cu addition promoted root growth under Cd stress and shifted Cd toward the root compartment, with the combined Cu + AM fungi treatment described as the strongest treatment for reducing Cd translocation while increasing root Cd accumulation. The result is useful as soil-to-plant-transfer and remediation context for cadmium, but it should not be used to infer Cd concentrations in edible crops.

Key numbers

• Design: 8 treatment groups from Cd addition/no Cd, Cu addition/no Cu, and AM fungi inoculation/no inoculation; 8 replicate pots per group; 64 pots total.
• Growth period: 90 days in a greenhouse at 25 C, 40-60% air humidity, 20-25% soil moisture, and a 12 h light/dark cycle.
• Substrate: 0.625 kg per pot of autoclaved campus soil, nutrient soil, and vermiculite at 1:1:1, sieved to 2 mm.
• Starting substrate measurements: pH 5.98, organic matter 5.21 g/kg, total nitrogen 937.04 mg/kg, Cd 0.56 mg/kg, and Cu 52.44 mg/kg. The paper also prints total phosphorus as 588.01 g/kg; that unit appears implausible and is not reused here.
• AM fungi inoculum: 20 g F. mosseae inoculum placed 5 cm below the substrate surface; inoculum described as soil with 176 spores/10 g, hyphae, and infected clover root fragments.
• Metal treatments: CdSO4 and CuSO4 solutions applied to sterilized soil at 20 mg/kg.
• Analytical method: Cd in soil and plant tissues measured by ICP-OES after HCl-HNO3-HClO4-HF digestion for soil and nitric acid-perchloric acid digestion for plant samples.
• Cd stress effect on roots: compared with the non-Cd control, root biomass decreased by 79.38%, root length by 15.98%, and root volume by 84.06%.
• AM fungi under Cd stress: root biomass increased by 1521.67% and root volume by 1600% relative to the Cd-stressed control; root length was not significantly affected.
• Cu under Cd stress: root length increased by 21.12% relative to the Cd-stressed control; biomass and volume were not significantly affected.
• Shoot Cd concentration: under Cd stress, AM fungi inoculation reduced shoot Cd concentration by 72.40%; combined AM fungi + Cu reduced shoot Cd concentration by 63.32%.
• Cd translocation factor: under Cd stress, TF decreased by 57.36%; with AM fungi inoculation by 57.70%; with Cu application by 32.96%. The combined Cu + AM treatment is described as having the greatest effect in limiting Cd movement from roots to shoots.
• Root Cd content under Cd stress: compared with the Cd-stressed control, AM fungi increased root Cd content by 82.26%, Cu increased it by 59.70%, and Cu + AM increased it by 839.28%.
• Soil Cd: Cd addition raised soil Cd content by 6505.02% relative to the no-added-Cd control. Under Cd stress, AM fungi increased measured soil Cd content by 1135.13%; Cu + AM increased it by 1207.39%.
• Root Cd bioconcentration factor: the source reports BCF values of 1018.59% for the Cu treatment and 366.08% for AM fungi inoculation; overall effectiveness for root Cd bioconcentration is reported as Cu > Cu + AM > AM.
• Root osmotic-response markers under Cd stress: AM fungi increased soluble sugar by 26.03% and proline by 268.82%; Cu increased soluble sugar by 9.36%, soluble protein by 20.68%, and proline by 205.44%; Cu + AM increased soluble sugar by 77.29% and proline by 445.62%.
• Antioxidant-response markers under Cd stress: Cu + AM reduced CAT activity by 74.67%, increased SOD activity by 5.81%, and decreased POD activity and H2O2 content by 26.31% and 73.12%, respectively.

Methods (brief)

Seeds of A. sinicus were sterilized, germinated, and transplanted into 10 cm by 14 cm plastic pots containing the autoclaved substrate. F. mosseae inoculum was placed below the surface before transplanting. CdSO4 and CuSO4 were applied at 20 mg/kg to create the treatment combinations. Plants were harvested after 90 days.

Root length, volume, dry biomass, and mycorrhizal colonization were measured. Cd was quantified in soil and plant tissue by ICP-OES. The authors calculated Cd translocation factor as shoot Cd divided by root Cd, and root Cd bioconcentration factor as root Cd content divided by soil Cd content. Root soluble sugars, soluble proteins, proline, MDA, H2O2, CAT, SOD, and POD were measured by spectrophotometric assays. Data were analyzed in Excel and SPSS using one-way ANOVA and Duncan’s multiple range test.

Implications

Certification: Do not route this source into product or ingredient occurrence pools. It is pot-experiment mitigation evidence showing how a microbial inoculant and Cu addition can alter Cd distribution in a remediation plant. The biomass intentionally accumulates Cd in roots and is not a food matrix.

Courses: Useful for teaching the difference between phytoremediation success and food safety. Root retention can be desirable for cleaning or stabilizing contaminated soil, but it does not mean the crop is safe for food or feed.

App: Context for cadmium soil-to-plant-transfer and agronomic mitigation notes. The source supports a candidate microbial/soil-amendment lever: F. mosseae plus Cu can reduce Cd translocation and retain more Cd belowground under controlled pot conditions.

Microbiome: Relevant to plant-root microbiome and arbuscular-mycorrhizal mitigation context because the intervention depends on F. mosseae symbiosis with A. sinicus roots.

Wiki pages this source may touch

• cadmium
• copper
• remediation-evidence
• agronomic
• soil-to-plant-transfer
• index

Verification notes

This page was built from the full PDF, including the experimental design, growth conditions, Cd/Cu treatment details, digestion and ICP-OES method, Figures 1-5, the results text, conclusion, and Data Availability statement. The source reports most treatment effects as percentages and graphical figures rather than full numeric concentration tables. This page preserves exact values from the text and avoids estimating bar-chart concentrations.

The layout extraction duplicated portions of the results section and produced one artifact reading of the Cu root-length effect as 621.12%; the raw text and second layout instance read 21.12%, which is retained here. The PDF’s starting total-phosphorus unit is printed as 588.01 g/kg, which is implausible for soil and therefore noted but not used as a key evidence value.

Speciation is not at issue for the reported Cd and Cu values. The study uses total cadmium and total copper in plant/soil matrices and does not report arsenic, mercury, or chromium species. No brand names are used for evidence routing; the seed supplier and instrument vendor are method/procurement context, not contamination-value brands.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.