Serpentine and Nonserpentine Achillea millefolium Accessions Differ in Serpentine Substrate Tolerance and Response to Organic and Inorganic Amendments

Abstract

Subgrade serpentine substrates are exceptionally difficult to revegetate due to multiple limitations including low N, P, and K, low Ca:Mg molar ratios, high levels of heavy metals including Ni, Cr, and Co, low organic matter, low CEC, and low water holding capacity. To examine the influence of plant origin on the success of the revegetation of serpentine substrates, granite and serpentine accessions of Achillea millefolium were grown on subgrade serpentine substrate amended with yard waste compost, slow-release NPK fertilizer, and/or CaSO 4 AE 2H 2 O (gypsum). The goals of this study were to: (1) identify the substrate amendment combination that maximized establishment of A. millefolium on serpentine substrate, (2) compare seedling establishment, survival, and growth of the serpentine and granite A. millefolium accessions in order to determine if a serpentine edaphic ecotype of A. millefolium exists and if this ecotype is superior to the granite accession for the establishment of vegetation on serpentine substrate and (3) if a serpentine edaphic ecotype of A. millefolium does exist, what physiological features with respect to mineral nutrition convey a higher tolerance of serpentine for this ecotype than the nonserpentine ecotype. Seedling establishment, survival, and growth were greatest for A. millefolium when the subgrade serpentine substrate was amended with 30% (v/v) compost and 220 mg kg substrate )1 each of N, P, and K. The serpentine A. millefolium accession displayed a greater tolerance of the subgrade serpentine substrate, serpentine topsoil, and the amended subgrade serpentine substrate than the granite accession. Higher capacity of the serpentine A. millefolium accession for selective Ca translocation from roots to the shoot resulted in a significantly higher shoot Ca:Mg molar ratio than the granite accession and appeared to be the most important physiological feature conveying greater tolerance of the serpentine accession for serpentine substrates.

Species specific plant-soil interactions influence plant distribution on serpentine soils

“…Our results have some important implications for restoration of vegetation or establishing shrub and tree islands on serpentine soil areas degraded by logging, (Halstead 1968;Fernandez et al 1999;O'Dell and Claassen 2006). Indeed, some of the most promising results to date in serpentine restoration/revegetation have been obtained using organic amendments (O'Dell and Claassen 2006).…”

“…Interestingly, we measured higher Fe, Mn, and Ni concentrations on vegetated than barren soils, but found the opposite pattern in foliage and roots of Achillea and Bromus grown on these soils. Vegetated soils were also significantly higher in organic matter, which has been shown to chelate heavy metals, reducing their uptake by plants (Halstead 1968;O'Dell and Claassen 2006). Fernandez et al (1999) measured increased available Mn and Ni with organic matter (peat moss) addition to a serpentine soil (perhaps because of a reduction in pH that made these metals more soluble) but decreased concentrations in plant tissue and increased biomass relative to plants on untreated serpentine soil.…”

“…Indeed, some of the most promising results to date in serpentine restoration/revegetation have been obtained using organic amendments (O'Dell and Claassen 2006). Although care should always be taken to minimize the distribution of weed seeds, it appears that the weed of greatest concern for this area, Bromus madritensis ssp.…”

“…Many bodenvag species have serpentine edaphic ecotypes that perform better on serpentine soils than nonserpentine ecotypes (Kruckeberg 1951;O'Dell and Claassen 2006;O'Dell and Rajakaruna 2011). Different species growing together on the same soils often have different foliar elemental concentrations, indicating different nutrient selectivities (Lyon et al 1971;Johnston and Proctor 1977;Koenigs et al 1982;Alexander et al 1989;Pope et al 2010).…”

Rock-type control of Ni, Cr, and Co phytoavailability in ultramafic soils

“…Other minerals such as magnetite are minor in both above mentioned rocks. Ultramafic soils are characterized by several specific traits: (a) low Ca/Mg ratio; (b) deficiency of nutrients such as: N, P and K and (c) high contents of Ni, Cr, and Co (Whittaker 1954;Kruckeberg 2004;O'Dell and Claassen 2006;Kazakou et al 2008;Oze et al 2008). All these characteristics cause ultramafic soils to be low productivity soils.…”