DOI: 10.5061/dryad.f4qrfj77m
title: Data from: Variations in root functional traits facilitate the adaptation of pioneer plants to rare earth element mine tailings

description: The trade-offs in plant root traits significantly influence the adaptation
 and community dynamics in heterogeneous habitats. However, the role of
 inter- and intraspecific root trait variation in the adaptation of pioneer
 plants in stressed mine tailings is poorly understood. We assessed root
 morphological and chemical traits of 16 dominant species from unexploited
 forest sites adjacent to rare earth elements (REEs) mine tailings, and
 three pioneer species (Miscanthus sinensis, Dicranopteris linearis, Pinus
 massoniana) across a gradient of soil stress—including REEs toxicity,
 nutrient deficiency, and compaction—from forest to REEs tailings. In the
 two-dimensional root economics space (RES), the contents of cellulose,
 hemicellulose, and silicon were coaxial with the collaboration gradients
 (“do-it-yourself” – “outsourcing”) and inversely related to fine root
 diameter. Meanwhile, root REEs content aligned with conservation gradients
 (“fast” – “slow”), indicating a slow strategy. Interspecific variations
 did not show a distinct strategy preference for pioneer species compared
 to non-pioneer plants. However, notable intraspecific variations were
 observed, particularly in stress-related traits such as root N content, C:
 N ratio, and REEs content, which exceeded interspecific variations. All
 three pioneer species exhibited a shift toward “slow” strategies, while P.
 massoniana also transitioned toward “do-it-yourself” strategies, driven by
 increased soil bulk density, elevated bioavailable REEs content, and
 reduced soil carbon and nutrient levels in the tailings. Our findings
 highlight the pivotal role of root chemical traits and intraspecific
 plasticity in facilitating the adaptation of pioneer plants to extreme REE
 tailing environments. The observed shifts toward stress-tolerant “slow”
 strategies and “do-it-yourself” nutrient acquisition provide a trait-based
 framework for advancing phytoremediation in the ecological restoration of
 degraded mine tailings, such as informing plant species selection.
description: # Data from: Variations in root functional traits facilitate the
 adaptation of pioneer plants to rare earth element mine tailings Dataset
 DOI: [10.5061/dryad.f4qrfj77m](10.5061/dryad.f4qrfj77m) ## Description of
 the data and file structure These datasets are derived from a field study
 investigating the role of root functional traits in facilitating the
 adaptation of pioneer plant species to rare earth element (REE) mine
 tailing environments. We measured root morphological and chemical traits
 for 16 dominant species in unmined forest habitats and three pioneer
 species (*Miscanthus sinensis, Dicranopteris linearis, and Pinus
 massoniana*) across a gradient of increasing edaphic stress, including REE
 toxicity, nutrient depletion, and compaction. The dataset supports
 analyses of inter- and intraspecific variation in root traits and their
 alignment with root economics strategies. For further details, please
 refer to the associated publication by Zhu et al. (titled “Variations in
 root functional traits facilitate the adaptation of pioneer plants to rare
 earth element mine tailings”) or contact the corresponding author. ###
 Files and variables #### File: 1_Plant_info.csv **Description:** The plant
 information in this study ##### Variables * Species: Scientific name
 (binomial) of the plant species sampled. * Family: Taxonomic family to
 which the species belongs. * Genus: Genus name of the plant. *
 Functional_group: Functional group classification used in trait-based
 analyses. Includes: tree, shrub, fern, and grass. Pioneer species are
 included in their respective growth forms. * Abbr.: Abbreviated species
 code used in trait datasets and figures. * Sampling_site: Habitat/site
 type where the species was sampled. Site codes include: Aband_REE (A) =
 abandoned REE tailings, Remed_REE (R) = remediated REE tailings, Forest
 (F) = unmined forest. #### File: 2_Soil_properties.csv
 **Description:** Physicochemical properties of bulk soil in three types of
 sampling sites. ##### Variables * sample ID: Unique identifier for each
 soil sample. Format: [Site Type] [Plot Number]-[Sample Number] bulk. Site
 types include: A = abandoned REE mine tailings, R = remediated REE mine
 tailings, F = unmined forest reference. Plot number and sample number
 distinguish spatial replicates within each site. * Moisture
 content: Gravimetric soil moisture content (%), calculated as the
 difference between fresh and oven-dried weight, divided by the oven-dried
 weight. Samples were oven-dried for 72 hours to a constant weight. *
 BulkDensity: Bulk density of soil (g/cm^3^), calculated by dividing the
 oven-dried weight by the volume of the soil cylinder (100 cm3), following
 USDA-NRCS (2001) protocol. * pH: Soil pH measured in a 1:2.5 (w/v)
 soil-to-water suspension using a calibrated pH meter (Mettler Toledo
 LE438, Germany). * CaCl~2~_Al: Exchangeable aluminum (Al) concentration
 (mg/kg), extracted using 0.01 M CaCl~2~ solution and measured with ICP-OES
 (Perkin Elmer, Avio 500). Reflects bioavailable Al. * Available_N:
 Available nitrogen (mg/kg), determined by the alkali diffusion method.
 Represents plant-available nitrogen in soil. * Available_P: Available
 phosphorus (mg/kg), determined by the Mo-Sb colorimetric method
 (antimony-molybdenum blue spectrophotometry). * Available_K: Available
 potassium (mg/kg), measured using flame atomic absorption spectrometry
 after extraction. * CaCl~2~_Mg: · Exchangeable magnesium (Mg)
 concentration (mg/kg), extracted with 0.01 M CaCl~2~ solution and
 quantified via ICP-OES. Reflects bioavailable Mg. * TOC: Total organic
 carbon (g/kg), determined by K~2~Cr~2~O~7~ heating oxidation-volumetric
 method. * Total_N: Total nitrogen content (g/kg), measured using the
 Kjeldahl distillation–titration method. * CN_ratio: Soil
 carbon-to-nitrogen ratio (C: N), calculated as the mass ratio of total
 organic carbon to total nitrogen. * CaCl~2~_REEs: Bioavailable rare earth
 element (REE) concentration (mg/kg), determined as the total concentration
 of 15 REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y)
 extracted by 0.01 M CaCl~2~ and measured using ICP-MS (Perkin Elmer,
 NexION 350D). #### File: 3_Plant_functional_traits.csv **Description:** 
 ##### Variables * Sample ID: Unique identifier for each root sample.
 Format: [Site code]-[Species code]-[Individual number], where site codes
 are A (abandoned), R (remediated), and F (forest). Species codes follow
 abbreviations in the Plant_info.csv file. * Specific root length: Root
 length per unit dry mass (cm g^-1^) * Specific root area: Root surface
 area per unit dry mass (cm2 g^-1^) * Fine root diameter: Average diameter
 of fine roots per sample (mm) * Root tissue density: Root dry mass per
 root volume (g cm^-3^) * Root dry matter content: Root dry mass per fresh
 mass (mg g^-1^) * Root nitrogen content: Nitrogen content in root tissue
 (%) * Root carbon content: Carbon content in root tissue (%) * Root
 carbon: nitrogen ratio: Ratio of RCC to RNC * Root phosphorus content:
 Phosphorus content in root tissue (mg kg^-1^) * Root cellulose content:
 Cellulose content in root tissue (mg g^-1^) * Root hemicellulose content:
 Hemicellulose content in root tissue (mg g^-1^) * Root lignin content:
 Lignin content in root tissue (mg g^-1^) * Root pectin content: Pectin
 content in root tissue (μmol g^-1^) * Root aluminium content: Aluminium
 content in root tissue (mg kg^-1^) * Root calcium content: Calcium content
 in root tissue (mg kg^-1^) * Root potassium content: Potassium content in
 root tissue (mg kg^-1^) * Root magnesium content: Magnesium content in
 root tissue (mg kg^-1^) * Root sodium content: Sodium content in root
 tissue (mg kg^-1^) * Root silicon content: Silicon content in root tissue
 (mg kg^-1^) * Root rare earth elements (REEs) content: Total REEs content
 in root tissue (mg kg^-1^) ## Code/software Microsoft Excel can be used to
 view the files ## Access information Other publicly accessible locations
 of the data: * None Data was derived from the following sources: * None