Data from: Density and root exudates mediate Arabidopsis response to copper
Data files
Nov 27, 2023 version files 10.88 KB
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Plant_Density_Experimental_Data_AJB_csv.csv
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README.md
Abstract
Premise of the study: Plants grown at high densities show increased tolerance to heavy metals for reasons that are not clear. A potential explanation is the release of citrate by plant roots, which binds metals and prevents uptake. Thus, pooled exudates at high plant densities could increase tolerance. We tested this exclusion facilitation hypothesis using mutants of Arabidopsis thaliana defective in citrate exudation.
Methods: Wild type Arabidopsis and two allelic mutants for the Ferric Reductase Defective 3 (FRD3) gene were grown at four densities and watered with copper sulfate at four concentrations. Plants were harvested before bolting and dried. Shoot biomass was measured, and shoot material and soil were digested in nitric acid. Copper contents were determined by atomic absorption.
Key results: In the highest copper treatment, density-dependent reduction in toxicity was observed in the wild type but not in FRD3 mutants. For both mutants, copper concentrations per gram biomass were up to seven times higher thanwild type plants, depending on density and copper treatment. In all genotypes, total copper accumulation was greater at higher plant densities. Plant size variation increased with density and copper treatment because of heterogeneous distribution of copper throughout the soil.
Conclusions: These results support the hypothesis that citrate exudation is responsible for density-dependent reductions in toxicity of metals. Density-dependent copper uptake and growth in contaminated soils underscores the importance of density in ecotoxicological testing. In soils with a heterogenous distribution of contaminants, competition for non-toxic soil regions may drive size hierarchies and determine competitive outcomes.
README: Data from: Density and root exudates mediate Arabidopsis response to copper
https://doi.org/10.5061/dryad.f1vhhmh1x
Data provides the biomass of individual Arabidopsis thaliana plants from three varieties grown at four densities in the presence of various concentrations of copper in soil.
Description of the data and file structure
Column A is the label of plant genotype: A = wild-type; B = frd3-3 mutant; C = frd3-1 mutant
Column B is pot number
Column C is replicate (1-4)
Column D is density (no. of plants per pot = 1, 3, 5 or 7)
Column E is the copper treatment level (micrograms per g in potting mix)
Columns F-L are the dry mass of individual plants
Column M is total micrograms of copper found after digestion of plant material (recovered from shoot mass)
"." indicates values that were not collected. For example, at a plant density of 1, dry mass values for plants 2-7 will be absent (".").
Methods
Biomass is for dry weight at harvest; copper concentrations were determined by atomic absorption following acid digestion of shoots.