Plant Soil (2014) 379:93–107 DOI 10.1007/s11104-014-2038-4
REGULAR ARTICLE
Elemental and stable isotope composition of Pinus halepensis foliage along a metal(loid) polluted gradient: implications for phytomanagement of mine tailings in semiarid areas Isabel Parraga-Aguado & Jose-Ignacio Querejeta & María Nazaret González-Alcaraz & Francisco J. Jiménez-Cárceles & Hector M. Conesa Received: 11 October 2013 / Accepted: 13 January 2014 / Published online: 12 February 2014 # Springer International Publishing Switzerland 2014
Abstract Background and aims Aleppo pine (Pinus halepensis Mill.) is a widely used species for restoring degraded semiarid areas, but its use for the revegetation of metal(loid) polluted soils has not been thoroughly investigated. The main goal of this research was to study the ecophysiological status and elemental composition of spontaneous populations of Pinus halepensis growing on mine tailings to assess their use in phytomanagement of mine spoils in semiarid climates.
Methods Edaphic characteristics and the physiological (by stable isotopes) and nutritional status of pine trees were determined on mine tailings, in the metalloidpolluted surroundings and a non-polluted control area. Results Low soil phosphorus availability at the tailings was found to be a more important limiting factor for pine physiological performance than high soil metal(lloid)s concentrations. Foliar phosphorus concentrations showed a strong negative correlation with foliar sulphur concentrations along the studied transect. The
Responsible Editor: Henk Schat. Electronic supplementary material The online version of this article (doi:10.1007/s11104-014-2038-4) contains supplementary material, which is available to authorized users. I. Parraga-Aguado : M. N. González-Alcaraz : H. M. Conesa (*) Departamento de Ciencia y Tecnología Agraria, Universidad Politecnica de Cartagena, Paseo Alfonso XIII, 48 30203 Cartagena, Spain e-mail:
[email protected]
F. J. Jiménez-Cárceles BIOCYMA. Consultora en Medio Ambiente y Calidad, S.L. C/Acisclo Díaz, N°9 4°K., 30005 Murcia, Spain e-mail:
[email protected]
I. Parraga-Aguado e-mail:
[email protected] M. N. González-Alcaraz e-mail:
[email protected] J.1 km
Control
Bulk Soil
(Bulk-T)
Fig. 1 Scheme of sampling transect
(USDA 1996); and 5) Organic Carbon (OC), by the oxidation of organic carbon using potassium dichromate. To determine total element composition, soil sub-samples were ground and analysed by X-ray fluorescence (Bruker S4 Pioneer). Water extractable ions (including metal(loid)s) and Dissolved Organic Carbon (DOC) were determined using the previous 1:5 soil/water mixture (Ernst 1996). The resulting extracts were filtered through nylon membrane 0.45 μm syringe filters (WICOM). DOC was measured by a TOC-automatic analyzer (TOC-VCSH Shimadzu). Major ions (cations: Na+, Ca2+, Mg2+, K+; anions: Cl-, SO42-) were analyzed using an ion chromatograph (Metrohm). Water extractable metal(loid)s (As, Cd, Cu, Mn, Pb, Zn) were analysed using an ICPMS (Agilent 7500A). Available phosphorus (AvailableP) was measured following the Olsen method (Olsen et al. 1954) after using 0.5 M NaHCO3 solution at pH 8.5 as extractant and measuring the extracted PO43- by a Lambda 25 UV/VIS spectrometer (Perkinelmer) at λ= 820 nm Soil microbiology was assessed by quantifying soil microbial biomass and two enzymatic activities: dehydrogenase and β-glucosidase. Unaltered portions of soil samples were stored at −20 °C for this purpose. Dehydrogenase activity was determined according to García et al. (1993) by measurement of INTF (iodonitrotetrazolium formazan) by spectrophotometry at 490 nm (Thermo Fisher Scientifc Multiskan GO) and reported as μg INTF g dry wt−1 h−1. β-glucosidase activity was determined according to the modification of Ravit et al. (2003) proposed by Reboreda and Caçador (2008) by measurement of pNP (pNitrophenol) by spectrophotometry at 410 nm and
reported as μmol pNP g dry wt−1 h−1. Soil Microbial Biomass Carbon (MBC) was estimated by the measurement of the extractable organic C by 0.5 M K2SO4 after a 24 h CHCl3-fumigation (Vance et al. 1987; Wu et al. 1990). Carbon in the resulting extracts was measured employing a TOC-automatic analyzer (TOC-VCSH Shimadzu). Plant samples were carefully washed with distilled water and dried at 65 °C for 72 h prior to grinding. For each sample, 0.1–0.5 g was incinerated prior to a suspension of the ash using concentrated nitric acid. The resulting extracts were filled to 25 ml and filtered through CHM F2041-110 ashless filter papers (20– 25 μm pore diameter). Then, metal(loid)s (As, Cd, Cu, Mn, Ni, Pb, Zn) were analysed using a ICP-MS (Agilent 7500A) and Cl, P and S were analysed using an ion chromatograph (Metrohm) while Ca, K, Mg and Na were analysed using a flame atomic absorption spectrometer (UNICAM 969 AA). Plant analyses were referenced using a CTA-VTL-2 certified material (Virginia tobacco leaves). The percentage of recoveries were 110 % for As, 89 % for Cd, 119 % for Cu, 104 % for Mn, 96 % for Pb and 100 % for Zn. Finely ground plant material was used for stable isotope measurements at the University of CaliforniaDavis Stable Isotope Facility. Leaf C, N, δ13C and δ15N analyses were conducted using a PDZ Europa ANCAGSL elemental analyzer interfaced to a PDZ Europa 20– 20 isotope ratio mass spectrometer (Sercon Ltd., Cheshire, UK). δ13C and δ15N data are expressed relative to international standards V-PDB (Vienna PeeDee Belemnite). Leaf δ18O analyses were performed using an elemental PyroCube (Elementar Analysensysteme GmbH, Hanau, Germany) interfaced to a PDZ Europa
Plant Soil (2014) 379:93–107
20–20 isotope ratio mass spectrometer (Sercon Ltd., Cheshire, UK). The final delta values are expressed relative to the international standard V-SMOW (Vienna Standard Mean Ocean Water). The long term standard deviation is 0.2 permil for 13C and 0.3 permil for 15N. Statistics Analysis of variance (one way ANOVA) with Tukey’s Test (p
