Data from: Testing the biogeochemical niche hypothesis using leaves, stems and roots of 62 Artemisia species across China
Data files
Dec 11, 2024 version files 187.23 KB
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elemental_concentrations.csv
186.50 KB
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README.md
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Abstract
The biogeochemical niche (BN) hypothesis is based on the concentrations of the predominant elements of a given organism to be stoichiometrically matched in order for it to function adequately. However, it is unknown how BN is represented by different plant organs and to what extent environment or evolution affects BN. We measured C, N, P, K, Ca and Mg concentrations in leaves, stems and roots of 1,022 individuals of 62 Artemisia species collected across China to quantify BNs of the three organs. The BN of leaves was offset from and smaller in volume than that of stems and roots. BNs of the three organs differed in their sensitivities to environmental gradients, and leaves were less responsive to environmental variation than stems and roots in both BN volumes and positions. Environmental gradients had larger effects on BN positions than on BN volumes of all three organs. The BN volumes and positions of leaves and roots had no phylogenetic signal, while stem BN had a weak signal, i.e. repeated species divergences from various Artemisia branches explained most of the BN variation of the three organs. Synthesis. The BN hypothesis cannot be fully tested using the elemental composition of a single organ owing to different physiological mechanisms and diverse responses of BN among organs. At least in Artemisia, leaves are strongly constrained in a limited elemental niche space to support a relatively stable supply of elements for leaf functioning, especially photosynthesis. In contrast, stems and roots develop larger elemental hypervolumes also representing nutrient storage and other functions. The BNs of Artemisia showed different environmental responses between volumes and positions, allowing these species to adjust elemental concentrations while maintaining the variation in overall elemental composition under different environmental conditions. In conclusion, BNs of extant Artemisia populations are determined mostly by short-term phenotypic responses to current environmental conditions and/or genotypic variation, while the recently evolved species diversity results mostly from species-specific and organ-specific use of nutrients and little by early divergence in the phylogeny.
README: Testing the biogeochemical niche hypothesis using leaves, stems and roots of 62 <i>Artemisia</i> species across China
https://doi.org/10.5061/dryad.np5hqc045
Description of the data and file structure
Elemental concentrations in leaves, stems, and roots of 62 Artemisia species across China
Files and variables
File: elemental_concentrations.csv
Description:
Variables
- Organ: plant organs
- Site: site number
- Species: species name
- NO: replicate of each species
- C: carbon concentration
- N: nitrogen concentration
- Ca: calcium concentration
- K: potassium concentration
- Mg: magnesium concentration
- P: phosphorus concentration
Methods
We sampled Artemisia from of natural communities in 81 sites across China in 2018. At each site, we identified all Artemisia species and collected mature individuals of each species but excluding those with damage or herbivore attack. The depth of the holes dug around the base of the plants was based on the plant size and was sufficiently deep to excavate the whole root system. In total, 1,022 individuals of 62 Artemisia species were sampled.
Each plant sample was separated into leaf, stem and root, and oven-dried at 65 °C for a minimum of 48 h. The root systems were cleaned with running water on a fine mesh sieve to remove sand, clay, litter and other matter before drying the samples. For element analysis (C, N, P, K, Ca and Mg, units are all mg/g), all leaves, whole stems, and whole roots were ground into fine powders. Total C and N concentrations were determined with an elemental analyzer (Vario Max CN Elemental Analyzer, Elementar, Hanau, Germany). For determination of the concentrations of P, K, Ca and Mg, samples were pretreated with an acid mixture of 1:4 of HClO4 (60%) and HNO3 (60%), digested in a MARS 5 microwave digestion system (CEM GmbH, Kamp-Lintfort, Germany) and determined using an inductively coupled plasma optical emission spectrometer (iCAP 6300 ICP-OES, Thermo Scientific, USA).