Search

The exposure of plants to weak magnetic fields (MFs) of various intensities and for different times is increasingly adopted to sustainably enhance plant growth in plant-based applications such as modern agriculture, phytoremediation and biogas production. However, little is known about the effects of MF exposure on plant chemical composition, and in turn on related ecosystem processes, such as the transfer of potentially toxic elements along food chains and the decomposition of organic matter. To fill this gap, the present research, through the study of the chemical composition of four edible crops (leaves of lettuce, parsley and basil, and fruits of tomato) differently exposed to weak MFs (75 Hz; 1.5 mT), aimed at evaluating the overall effects of the exposure on ecosystem processes. In particular, several essential (B, C, Ca, Cu, K, Fe, Mg, Mn, Mo, N, Ni, P, S, Zn), beneficial (Co, Na, Se, Si) and non-useful (Al, As, Ba, Cd, Cr, Li, Pb, Sr, Ti, V) elements, together with chemical compounds and derived parameters (soluble sugars, starch, chlorophylls, flavonoids, anthocyanins, nitrogen balance index), indicators of plant metabolism and health, and litter decomposability traits (C/N, C/P), were analyzed. Notwithstanding the expected variations in the observed effects among species and MF exposure conditions, the obtained results highlight a general decrease in most of the studied parameters (with the exception of those related to litter decomposability), attributable to a lower absorption/accumulation of the studied chemical elements and to a reduced synthesis of metabolites. The largest average reduction was observed for the non-useful elements, which outweighs the reduction in essential and beneficial elements and provides for an important MFinduced effect, considering their toxic, persistent and biomagnificable characteristics. Similarly, the induced increases in C/N and C/P ratios indicate the production of litter more recalcitrant to the decomposition process, suggesting that weak MF treatments may be useful to enhance soil C storage and reduce CO2 emissions.

With a view of shedding light on the accumulation capability of the epigeous organs of common reed (Phragmites australis), employed worldwide in metal biomonitoring, an accumulation study of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was performed, focusing on leaves belonging to different whorls and culms. To this end, in five sampling sites on the littoral zone of the volcanic Lake Averno (Italy), and in one occasion (autumn) before plant senescence, leaves of different ages and culms were collected and analyzed for metal concentrations. In terms of the suitability for biomonitoring, culms demonstrated poor performances in relation to the low metal accumulation and the difficulties in sampling and processing, whereas leaves proved their effectiveness in highlighting whole plant exposure. Since the accumulation degree of Cr, Cu, Fe and Zn is unaffected by leaf age, the pooling of leaves from different whorls is advisable to improve the representativeness of samplings. This strategy becomes mandatory in the case of Ni, the non-monotonic age-dependent variations of which would affect the derivation of contamination gradients otherwise. For Mn, Cd and Pb, the accumulation patterns strictly dependent on age can instead be exploited in selecting the sensitivity of biomonitoring by focusing on the organs where they are preferentially accumulated: old leaves for Mn and young leaves for Cd and Pb.

Anthropogenic pressures can affect the distribution of species and elicit the appearance of spatial patterns that provide insights into the species’ responses to environmental filtering, mediated by their functional traits. Due to the functional redundancy in ecological communities, the spatial variations of species and functional traits can occur at different scales, but little is known on this topic, especially for soil arthropods with limited dispersion capabilities and highly dependent on environmental characteristics. The present research aims at shedding light on the spatial ecology of both the taxonomic and functional biodiversity of collembolan communities colonizing urban parks, adopted as model taxa for their functional traits, diversity and sensitivity to environmental drivers. To this end, the spatial patterns and scales of collembolan communities from 8 parks in Naples (Italy) and 14 in Montpellier (France) were investigated through an approach based on Moran eigenvector maps, modified to allow for evaluating the community spatial connectivity and the scales underpinning the spatial variation of each species and functional trait. The obtained findings demonstrate a limited spatial connectivity of collembolan communities in terms of both taxonomic and functional diversity, with mostly species-specific micro-scale variations that may be shaped by environmental constraints.

Evaluating the relative weight of the choice of cultivar and soil fertilization on potentially toxic elements (PTEs) accumulation is crucial in promoting informed decisions in the framework of regenerative agriculture. To this end, 11 PTEs (Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Zn) were determined in both leaves and roots of six cultivars (Stylist, Xanadu, Aljeva, Bacio, Analena, Vincenzo) of lettuce (Lactuca sativa L.) grown side by side on mineral fertilized or biowaste compost amended soils, under greenhouse conditions. The use of multivariate and linear modelling approaches indicated that the organ and cultivar primarily account for the variability in PTE concentrations. In terms of PTE partitioning between organs, Cd and Mg were preferentially accumulated in leaves, whereas Cu, Pb, K and Zn in roots. As for the cultivar, Xanadu showed the highest concentrations of several PTEs, with Cd reaching concerning levels. Fertilization had a detectable contribution only on Cd accumulation, slightly increased in leaves by compost. Findings highlight the key role of cultivar choice in guaranteeing food safety and grant the possibility to adopt biowaste compost in regenerative agriculture without concerns about PTE accumulation enhancements in lettuce, but demand a cautionary approach in the case of Cd.

Environmental monitoring in sensitive areas is crucial to develop and adapt governance policies. In this context, biomonitoring provides information not only on environmental contamination gradients, but also on the actual pollutant bioavailabilities and, using bioaccumulators, on their possible transfer through the food webs. The spatial distribution of suitable bioaccumulators, however, may limit the effectiveness of biomonitoring. To relieve this constraint, we investigated the usefulness of Mentha aquatica as a novel cosmopolitan biomonitor of potentially toxic elements (PTEs) in freshwater ecosystems, using Helosciadium nodiflorum, a widely recognized biomonitor, as a reference for environmental concentration gradients. The biomonitors were then employed in deriving spatial gradients of macronutrient (Ca, K, Mg, P, S), micronutrient (Co, Cr, Cu, Fe, Mn, Na, Ni, Si, V, Zn) and non-essential element (Al, As, Cd, Pb) concentrations in the area of one of the largest Italian national parks. Over two years and a large number of sites, M. aquatica roots provided PTE concentration gradients comparable to those obtained using H. nodiflorum roots, demonstrating their usefulness in PTE biomonitoring and widening the range of suitable biomonitors for freshwater ecosystems. At the same time, the joint use of M. aquatica and H. nodiflorum enhanced the accuracy of concentration gradients measured in two of the main freshwater ecosystems within the “Cilento, Vallo di Diano e Alburni” National Park (southern Italy). The study, performed for two consecutive years over 43 sites along the Bussento and Calore Salernitano rivers, pointed out several criticalities, attributable either to natural or anthropogenic sources. High natural concentrations of Al, As, Na, Si and V were mainly related to local characteristics (proximity to sea, sediment texture) or generalized lithological background (pyroclastic deposits on carbonates), whereas local high concentrations of Co, Fe and Mn were mainly related to direct or indirect anthropogenic sources (proximity to urban centers, wastewater treatment plants). Moreover, unusual high concentrations of Cd, Cr, Ni and Zn were observed at three spring mouths, suggesting changes in their bioavailability due to spring water physico-chemistry.

In statistics, the identification of environmental criticalities, one of the primary goals of environmental monitoring and management, translates into the detection of spatial outliers. Detected in relation to purposely defined sets of indicators, both global and local outliers are pivotal in the identification not only of the severity and spread of criticalities, but also of their nature and causes. The present research exemplifies a procedural framework to identify environmental criticalities, using two different approaches for the detection of spatial outliers in river ecosystems related to several sets of parameters (organic C, inorganic C, Ca, Co, Cr, Fe, K, Mg, Mn, N, Na, P, S, Si, V, Zn, Cl-, F-, NO3-, SO42-, chlorophyll a, chlorophyll b, pheophytin a, pheophytin b, total carotenoids, pH, and electrical conductivity), including emerging contaminants. To this end, indicator sets diagnostic for specific criticalities, derived from an empirical dataset of water quality parameters, were employed, using detection techniques based on geographically weighted principal component analysis and a modified pairwise Mahalanobis distance-based algorithm. Clear and accurate criticality scenarios were derived, highlighting both the strengths and the limitations of the proposed approach, especially in relation to the classic threshold-based methods.

The Sarno River is considered the most polluted river in Europe and one of the ten most polluted rivers in the world. So far, its quality has been usually evaluated by water and sediment analyses of either inorganic or organic pollutants. However, a biomonitoring approach would be of paramount importance in the evaluation of river quality, since it integrates pollutant temporal fluctuations, as in the case of discontinuous inputs from urban, industrial and agricultural activities. To this end, a passive biomonitoring study of the Sarno River was carried out, using two native aquatic plants accumulators of inorganic pollutants. The spring area was monitored analysing the roots of the semi-submerged Apium nodiflorum, whereas the whole river course was monitored analysing the shoots of the submerged Potamogeton pectinatus. The information on the four macronutrient (Ca, K, Mg, P), the six micronutrient (Cu, Fe, Mn, Na, Ni, Zn) and the four toxic element (Cd, Cr, Pb, V) concentrations were separately combined in the Nemerow Pollution Index. Results evidenced a severe pollution degree of the Sarno River, attributable to toxic elements > micronutrients > macronutrients. In particular, the spring area showed high K concentrations, as well as high concentrations of several micronutrients and toxic elements. A generalized Zn contamination and a progressive macronutrient (above all Ca and P), micronutrient (above all Ni, Cu and Fe) and toxic element (above all Cr and Pb) accumulation toward the mouth was related to pollution from agricultural and urban activities. Industrial sources, especially tanneries along the Solofrana tributary, accounted for high Mn concentrations, whereas the volcanic origin of the substrate accounted for a generalized V contamination.

Antibiotics are emerging pollutants released into the environment through wastewater and manure or effluents from livestock plants. Compared to the wide literature on the effects of antibiotics on the development of drugresistant bacteria and on the adverse effects on animals and human beings, the effects on plants are less investigated. Here we evaluated the effects of four antibiotics (cloramphenicol: CAP, spiramycin: SPR, spectinomycin: SPT, vancomycin: VAN) belonging to different chemical groups, on seed germination and root development of tomato (Solanum lycopersicum L. cv. San Marzano). Specifically, seed germination and root elongation kinetics, as well as the number of mithotic figures in root apical meristem, were studied in relation to different concentrations of each antibiotic (0, 0.1, 1, 10, 100, 1000 mg L−1) for 10 and 7 days, respectively. Results showed that seed germination was not affected, but root development (root elongation kinetics and cell division) was impaired at concentrations from 10 mg L−1 (SPT) and 100 mg L−1 (CAP) to 1000 mg L−1 (SPR and VAN).

Aim: Understanding and quantifying the seasonal patterns in biodiversity of phyto- benthos, macro-zoobenthos and fishes in Mediterranean coastal lagoons, and the species dependence upon environmental factors. Location: The study was carried out in the “Stagnone di Marsala e Saline di Trapani e Paceco,” the largest coastal lagoon system in the central Mediterranean Sea (Sicily, Italy), a Special Protection Area located along one of the central ecological corridors joining Africa and Europe. Methods: The coastal lagoon system was selected as a model ecosystem to investi- gate the seasonal variations in biodiversity indices and dominance–diversity relation- ships in phytobenthos, macro-zoobenthos and fishes, and how seasonal variations in temperature, salinity, depth, inorganic and organic suspended matter affect the abundance of the species constituting these communities. Models of ecosystem structure, describing the interactions among functional groups and environmental variables, were also developed using confirmatory path analysis and artificial neural networks to exemplify their application in predicting temperature-driven alterations. Results: Wide seasonal variations in biodiversity indices and dominance–diversity relationships across the communities of the coastal lagoon system were observed, driven by the dynamics in climate and resource availability. The effects of the envi- ronmental variables on taxon abundances varied in relation to the community, with the widest responses elicited in phytobenthos and fishes. Temperature was the main variable affecting taxon abundances in macro-zoobenthos and was also the major driver of shallow water ecosystem structure. Main conclusions: This research shed light on the seasonal variations in biodiversity of Mediterranean coastal lagoons, elucidating also the tight dependence of phytob- enthos, macro-zoobenthos and fish diversity upon environmental factors. The find- ings and the methodological approach proposed may be crucial in developing models able to predict future climate-driven alterations in communities inhabiting these im- portant and threatened ecosystems.

Copper is an essential element for all living organisms; however, it becomes toxic at high concentrations due to its ability to participate in many redox reactions. This vital micronutrient balance plays an important role in the battle between host and pathogen, due to its use by the host to intoxicate pathogens. In this study, we explore the effects of copper deprivation on Helicobacter infection in mice using the copper chelator tetrathiomolybdate. Our results reveal that Helicobacter infection significantly reduces copper concentration in mice stomachs without affecting its circulating levels. Moreover, in copper-deprived mice, bacteria hardly colonize the epithelium and mice show less gastric damage in comparison with the infected ones. However, when the copper chelator is administered after infection, the condition of the mouse stomachs declines. This could be explained by the lower copper availability in tetrathiomolybdate-treated mice, which would reduce macrophages' action against the pathogen. In this scenario, we observe that the protective factor trefoil factor 1 is induced upon copper-deprived conditions, probably contributing to the inefficacy of infection, whereas, when the chelator is administered after infection, the gene is already silenced by bacteria and cannot be restored. In conclusion, our data suggest that Helicobacter takes advantage of gastric copper reducing its availability for the host and that copper levels have an impact on the outcome of infection.

Unlike the spectacular speleothems that can often be found in numerous caves, vermiculations are rather unassuming formations, whose origin and evolution still subject of several heated debates. In order to provide a quantitative basis for the understanding of the nature and evolution of vermiculations in karst environments, the geochemical properties of one of the most important karst systems of southern Italy, the Pertosa-Auletta Cave, were studied through a comprehensive approach which included elemental, mineralogical and microscopy analyses. The chemical element abundances, mineral composition and microstructure of the vermiculations covering the entire range of morphologies and colours observed in the case-study cave were investigated, thus providing the first quantitative record of these traits. The vermiculations presented exceptional diversity in their morphology, colour, chemical and mineral composition, with it being due to exogenous determinants such as the deposition of stream sediments or organic matter as well as the development of photoautotrophic communities. They were invariably composed of calcite, associated to quartz as well as clays and other secondary minerals, the formation of which may be biologically mediated. This occurrence, and the evidences of microbial activity observed through dissolution traces, support the possible involvement of biogenic processes in vermiculation development.

Microbial degradation is the main responsible for polycyclic aromatic hydrocarbons (PAHs) removal from contaminated soils, and the understanding of this process is pivotal to define effective bioremediation approaches. To evaluate the contribution of several microbial groups in soil anthracene and benzo[a]pyrene degradation, the analysis of phospholipid fatty acid (PLFA) profiles and machine learning techniques were employed. To this end, PLFAs and PAH concentrations were analysed, along 274 days of incubation in mesocosms, in soils artificially contaminated with anthracene and benzo[a]pyrene, subjected to different treatments: untreated soil and soils treated with biowaste compost or fungal consortium. Random forest models, figuring anthracene or benzo[a]pyrene concentrations as dependent variables and PLFAs as predictors, were then built to evaluate the contribution of each variable in PAH degradation. PLFA profiles varied substantially among soil treatments and along time, with the increase of Actinomycetes in soils added with fungi and other Gram+ bacteria in compost amended soils. The former, together with fungi, are primarily responsible for anthracene and benzo[a]pyrene degradation in both treated soils, a process in which also metanotrophs and other Gram+ and Gram- bacteria participate. In untreated soil, the cooperation of a multitude of different microorganisms was, instead, responsible for PAH removal, a process with lower efficiency in respect to treated soils.

BACKGROUND Tomato (Solanum lycopersicum L.) is one of the most important crops in the world and represents a key crop in southern Italy. With the aim to evaluate the nutritional characteristics of tomato fruits in relation to NPK and compost fertilisation, the concentrations of the main nutrients, toxic elements, primary metabolites and total phenols were determined in two varieties (Lido and San Marzano). Each variety was cultivated in a different experimental field, subjected to different agronomic techniques. RESULTS Concentrations of toxic elements (Cd and Pb) were below the limits indicated by the EU Regulation (2011) in all the fruits analysed. Moreover, fruits obtained from San Marzano plants grown on organic amended soils showed a better overall quality than those obtained on mineral fertilised soil, being characterised by lower N (attributed to lower nitrate and nitrite concentrations), lower Cd, and higher soluble sugar concentrations. Higher concentrations of soluble sugars in fruits from organic amended soils were also observed in the Lido variety. CONCLUSIONS The agricultural use of quality compost represents an effective strategy to obtain high quality products in an economically and environmentally sustainable way. © 2016 Society of Chemical Industry.

DOI of original article:https://doi.org/10.1016/j.catena.2019.104178 .- Rosangela Addesso, Alessandro Bellino, Ilenia Maria D'Angeli, Jo De Waele, Ana Zelia Miller, Cristina Carbone, Daniela Baldantoni: Vermiculations from karst caves: The case of Pertosa-Auletta system (Italy) CATENA, Volume 182, November 2019, Pages 104178

In order to validate the use of compost in soil PAH bioremediation, the degradation of anthracene and benzo(a)pyrene was monitored in soils artificially contaminated and incubated in mesocosms under controlled conditions. The dynamics observed in compost amended soil were compared to those observed in soil added with a fungal consortium and untreated soil. At the same time, three microbial enzyme activities usually involved in PAH degradation (laccase, o-diphenol oxidase and peroxidase activities) were monitored. Both PAHs decreased along the time in the three mesocosms, with anthracene, with lower molecular weight, degrading with a higher rate and reaching lower residual values than benzo(a)pyrene. Although at the end of incubation, the residual values of investigated PAHs are similar in the three mesocosm types, PAH dynamics showed a higher degradation rate in the early stage in mesocosms added with the fungal mycelium and amended with compost. Among the three enzyme activities, only peroxidase showed higher values in treated than untreated mesocosms. Considering the ameliorating effects of compost on degraded soils, its use can be suggested in PAH bioremediation.

Post-fire reproductive niche of Aleppo pine (Pinus halepensis) is deeply interlaced with fire products. Indeed, the high pH and low osmotic potentials of ash beds under burnt crowns constitute the main constraints to seed germination. In this study, we aim to investigate whether fire recurrence, through the physico-chemical constraints imposed by the ash beds, affects the reproduction ability of P. halepensis at the germination stage. To this aim, Aleppo pine seeds were collected in neighboring even-aged stands subjected to 0, 1, or 2 fires (namely fire cohorts), and seed morphology and germination performance, in terms of cumulative germination and germination kinetics, were studied under increasing osmotic potentials (from 0.0 to −1.2 MPa) and pH (from 6 to 11). Besides fire history, the role of ontogenetic age of mother plants on seed morphology and germination was also investigated. Differences in seed morphology among the three cohorts have been highlighted in a multivariate context, with anisotropic enlargement of the seeds produced by pine stands experiencing repeated fires. The patterns of seed germination varied primarily in relation to the fire cohort, with seeds from the pine stand experiencing repeated fires exhibiting enhanced tolerance to pH stress. Conversely, germination performances under osmotic constraints mainly depends on tree ontogenetic stage, with an involvement of fire history especially in the timing of seed germination. Our results suggest that, at least in the short term, fire recurrence does not constrain the reproduction ability of Aleppo pine. These results highlight the need for further research to elucidate the mechanisms behind these responses to recurrent fires.

Urban parks provide esthetic and recreational services and improve the quality of life in cities. Sometimes considered as biodiversity hot-spots in cities, they are subjected to different management practices which may affect soil biological quality. This is the first study – performed in urban parks of Naples (southern Italy) – aiming to evaluate the effects of park history (age, previous land use of the area and soil origin), urbanization (sealed surface density of park neighborhood), current management (land cover type and litter presence/absence) or soil physico-chemical properties on collembolan communities diversity, as indicators of soil biological quality. Our results showed that the maintenance of specific land cover types and the presence of a litter layer were crucial factors in favoring high collembolan richness in urban parks, likely by ensuring adequate trophic resources and spatial niches. In addition, park age, urban density and previous land use of areas may be involved in shaping collembolan communities. Indeed, the most diverse and structured communities inhabit soils of the oldest urban park, with the lowest surrounding urban density and mild land use change.

Partially mycoheterotrophic (mixotrophic) plants gain carbon from both photosynthesis and their mycorrhizal fungi. This is considered an ancestral state in the evolution of full mycoheterotrophy, but little is known about this nutrition, and especially about the physiological balance between photosynthesis and fungal C gain. To investigate possible compensation between photosynthesis and mycoheterotrophy in the Mediterranean mixotrophic orchid Limodorum abortivum, fungal colonization was experimentally reduced in situ by fungicide treatment. We measured photosynthetic pigments of leaves, stems, and ovaries, as well as the stable C isotope compositions (a proxy for photosynthetic C gain) of seeds and the sizes of ovaries and seeds. We demonstrate that (1) in natural conditions, photosynthetic pigments are most concentrated in ovaries; (2) pigments and photosynthetic C increase in ovaries when fungal C supply is impaired, buffering C limitations and allowing the same development of ovaries and seeds as in natural conditions; and (3) responses to light of pigment and (13)C contents in ovaries shift from null responses in natural conditions to responses typical of autotrophic plants in treated L. abortivum, demonstrating photoadaptation and enhanced use of light in the latter. L. abortivum thus preferentially feeds on fungi in natural conditions, but employs compensatory photosynthesis to buffer fungal C limitations and allow seed development.

SUMMARYCompost use is increasingly proposed as a sustainable strategy to restore the fertility of degraded agricultural soils and to reduce landfill disposal or incineration of organic wastes. The effects of compost application on many soil physico-chemical and biological properties, as well as on soil contamination, have been investigated widely, but a model for the ecological interactions among them has never been developed. The aim of the present paper was to provide an integrated view of the causal processes induced by repeated compost amendments on agricultural soil properties. For this purpose, a confirmatory path analysis was performed to enable inferences to be drawn about the causal processes involving compost amendment, soil organic matter content, nutrient concentrations, microbial activity and soil contamination. The path analysis was performed on a dataset derived from a 3-year field trial carried out by the current authors in a Mediterranean intensive agricultural system, where 0, 15, 30 or 45 t/ha of certified compost from municipal solid wastes were annually applied. A script (‘cpa’) was developed using the R programming language and used to test 13 hypothetical models, expressed as directed acyclic graphs, against the observed data. Within the above-mentioned dataset, potassium and zinc available concentrations, microbial respiration and total polycyclic aromatic hydrocarbon (PAH) concentrations were selected as indicative of soil nutrient availability, microbial activity and organic contamination. The applied approach highlights that compost amendment directly influences all the other variables considered in the study and is the main determinant of the observed trends. Other important relationships are those among organic matter, nutrient availabilities, respiration and PAHs, as well as their temporal dynamics.

Tomato (Solanum lycopersicum L.) is one of the most important crops in the world and represents a key crop in southern Italy. With the aim to evaluate the nutritional characteristics of tomato fruits in relation to NPK and compost fertilisation, the concentrations of the main nutrients, toxic elements, primary metabolites and total phenols were determined in two varieties (Lido and San Marzano). Each variety was cultivated in a different experimental field, subjected to different agronomic techniques.Concentrations of toxic elements (Cd and Pb) were below the limits indicated by the EU Regulation (2011) in all the fruits analysed. Moreover, fruits obtained from San Marzano plants grown on organic amended soils showed a better overall quality than those obtained on mineral fertilised soil, being characterised by lower N (attributed to lower nitrate and nitrite concentrations), lower Cd, and higher soluble sugar concentrations. Higher concentrations of soluble sugars in fruits from organic amended soils were also observed in the Lido variety.The agricultural use of quality compost represents an effective strategy to obtain high quality products in an economically and environmentally sustainable way. © 2016 Society of Chemical Industry.

Chemometric analysis applied to diffuse reflectance spectroscopy is increasingly proposed as an effective and accurate methodology to predict soil physical, chemical and biological properties. Its effectiveness, however, largely varies in relation to the calibration techniques and the specific soil properties. In addition, the calibration of UV-Vis-NIR spectra usually requires large datasets, and the identification of techniques suitable to deal with small sample sizes and high dimensionality problems is a primary challenge. In order to investigate the predictability of many soil chemical and biological properties from a small dataset and to identify the most suitable techniques to deal with this type of problems, we analysed 20 top soil samples of three different forests (Fagus sylvatica, Quercus cerris and Quercus ilex) in southern Apennines (Italy). Diffuse reflectance spectra were recorded in the UV-Vis-NIR range (200-2500 nm) and 22 chemical and biological properties were analysed. Three different calibration techniques were tested, namely the Partial Least Square Regression (PLSR), the combinations wavelet transformation/Elastic net and wavelet transformation/Supervised Principal Component (SPC) regression/ Least Absolute Shrinkage and Selection Operator (LASSO), a kind of preconditioned LASSO. Calibration techniques were applied to both raw spectra and spectra subjected to wavelet shrinkage filtering, in order to evaluate the influence on predictions of spectra denoising. Overall, SPC/LASSO outperformed the other techniques with both raw and denoised spectra. Elastic net produced heterogeneous results, but outperformed SPC/LASSO for total organic carbon, whereas PLSR produced the worst results. Spectra denoising improved the prediction accuracy of many parameters, but worsen the predictions in some cases. Our approach highlighted that: (i) SPC/LASSO (and Elastic net in the case of total organic carbon) is especially suitable to calibrate spectra in the case of small, high dimensional datasets; and (ii) spectra denoising could be an effective technique to improve calibration results.

In this study, the phytoextraction capacity of a heavy metal tolerant white poplar clone, grown in the presence of high iron availability and/or mycorrhizas was evaluated. A large amount of iron in available form was determined in initial high concentrations in leaf, which declined along time and affected Cd, Cu, Pb and Zn accumulation. Natural and artificial mycorrhization did not influence these dynamics.

Background The populations of Soldanella (Primulaceae) of the southern Apennines (Italy) are unique within the genus for their distribution and ecology. Their highly fragmented distribution range, with three main metapopulations on some of the highest mountains (Gelbison, Sila and Aspromonte massifs) of the area, poses intriguing questions about their evolutionary history and biogeography, and about the possibility of local endemisms. Aims and methods In order to clarify the phylogeny and biogeography of the three metapopulations of Soldanella in the southern Apennines, attributed to S. calabrella to date, and to identify possible local endemisms, a comparative approach based on the study of molecular, morphological and ecological characteristics of the populations was employed. Specifically, one nuclear (total ITS) and two plastid (rbcL and trnL) markers were used for the phylogenetic analyses, performed through both maximum likelihood and Bayesian techniques. Among the morphological features, the glandular hair and leaf biometric traits were analysed, and the environment in which the populations grew was characterised for altitude, forest canopy composition and soil pH, C, N and organic matter. Results and conclusions Our findings demonstrate that the lineage of Soldanella of southern Italy diverged from the Carpathians lineage during the Middle Pleistocene, and underwent an evolutionary radiation during the Late Pleistocene. The populations of the Sila and Aspromonte massifs diverged from the populations of the Gelbison massif around 380000 years ago and are probably undergoing a progressive differentiation due to their isolation. The populations on the Gelbison massif, moreover, have different morphological features from those of the Sila and Aspromonte massifs and a different ecological niche. The molecular, morphological and ecological data clearly demonstrate that the metapopulation of Soldanella on the Gelbison massif belongs to a new taxonomic unit at the species level, which we name Soldanella sacra A. & L. Bellino from the name of the massif on which it was discovered, the “Holy Mountain”. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0433-y) contains supplementary material, which is available to authorized users.

A vegetation analysis was carried out on a degraded agricultural soil of the Mediterranean area (Campania region, southern Italy) in order to study the effects of different fertilization practices (quality compost, mineral fertilizers, mixed fertilization, and no fertilization) on the whole spontaneous vegetation community. The study was performed for two consecutive years at three different scales (species level, community structure, and community properties), using three different units of abundance (number of individuals, biomass, and cover of each species). The observations were carried out in spring, after 5 and 6 years of soil treatments, on a total area of 4 m(2) for each soil treatment and in each year. The different fertilization practices did not determine changes in species composition; however, the relative abundance of dominant species increased in compost and mixed fertilized soils, particularly in the second year of observation. Although the dominance and diversity were unaffected by the different fertilization practices, the total biomass and total number of individuals increased in compost-amended soils. These results indicate the effectiveness of soil quality compost amendments to enhance natural revegetation, a key step in the recovery of degraded areas.

Plant biodiversity and intra-population genetic variability have not yet been properly exploited in the framework of phytoremediation and soil reclamation. For this reason, iron and other metal accumulation capacity of two Cu and Zn tolerant poplar clones, namely AL22 (Populus alba L.) and N12 (Populus nigra L.), was investigated in a pot experiment. Cuttings of the two clones were planted in iron rich soil collected from an urban-industrial area. Concentrations of Cd, Cu, Fe, Pb and Zn were analysed in leaves (at different times), as well as in stems and in roots (at the end of the experiment), both in control plants and in plants grown on a soil whose Fe availability was artificially enhanced. Results showed that Cd and Zn were preferentially accumulated in leaves, whereas Cu, Fe and Pb were mainly accumulated in roots. The main differences in metal accumulation between clones were related to Cd (about tenfold higher concentrations in N12) and Cu (higher concentrations in AL22). Once soil Fe availability was enhanced, the uptake and accumulation of all metals declined, with the exception of Fe at the first sampling time in AL22 leaves. The different behaviour of the two poplar clones suggests that a thoughtful choice should be made for their use in relation to soil heavy metal remediation.

The evaluation of changes in litter decomposition rate due to increasing trend in tropospheric ozone is an emerging field of investigation, providing relevant information on long-term forest ecosystem sustainability. This research aims to clarify the effects of ozone exposure on Quercus ilex leaf chemical composition and decomposition slow down. Young plants were fumigated in growth chambers at a cumulative dose of 17.15 ppm h. To assess the fumigation effectiveness, stomatal conductance and net photosynthesis were monitored. Leaves were analysed for C, N, S, Ca, Mg, K, Fe, Zn, Mn, total soluble sugars, starch, acid-detergent fibre (ADF), lignin and cellulose prior to the incubation in litter bags in mesocosms, and during decomposition along 395 days. Ozone-exposed leaves showed a significant reduction in net photosynthesis and stomatal conductance but did not differ from control leaves in all the chemical parameters analysed. Nevertheless, leaf decomposition rate was lower in treated leaves. The main differences between the models describing the mass loss in exposed and control leaves were played by ADF for exposed leaves and by lignin for control leaves, as well as by N, that showed a greater contribution in the model for the exposed leaves. Ozone fumigation of Q. ilex results in leaf litter decomposition slowing down, mainly due to ADF joint dynamics with the other variables describing mass decay, even if no detectable changes in initial leaf composition occur.