V. De Dominicis

The nickel hyperaccumulator plant Alyssum bertolonii as a potential agent for phytoremediation and phytomining of nickel

Abstract Experiments were carried out in Italy on the potential use of the hyperaccumulator Alyssum bertolonii in phytomining of ultramafic soils for Ni. In situ experimental plots at Murlo, Tuscany were fertilized with various regimes during a 2-year period. The best fertilizer treatment (N + K + P) gave a threefold increase of the biomass of reproductive matter to 9.0 t/ha without dilution of the unfertilized Ni content. A Ni content of 0.8% in dry matter (11% in ash), would give a Ni yield of 72 kg/ha without need of resowing for a further crop. There was no correlation between the age of a plant and its Ni content. The long-term cropping sustainability of the soils was simulated by sequential extractions with KH phthalate solutions at pH 2, 4 and 6 that showed a limiting available Ni content of 768 μg/g. Thus just over seven croppings at pH 6 in the rhizosphere would reduce the available Ni pool by 30%. A proposed model for phytomining involves harvesting the crop after 12 months and burning the material to produce a sulphur-free bio-ore with about 11% Ni. Utilising the energy of combustion is also discussed. It is considered that Alyssum bertolonii or other Alyssum species might be used for phytomining throughout the Mediterranean area including Anatolia, as well as in Western Australia and the western United States. The economic limits of phytomining are proposed and at current world prices, the technique would only be feasible for Ni and Co with plants of at least the same biomass as Alyssum . Plants of higher biomass and similar uptake potential as for Ni, could extend the limits to other elements.

Soil contribution to the elemental composition of epiphytic lichens (Tuscany, central Italy)

Total concentrations of Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Sr, Ti, V and Zn in the epiphytic lichen Parmelia sulcata and superficial soils from 60 remote sampling sites in Tuscany (central Italy) were determined to evaluate the contribution of soil to the elemental composition of the lichen. The results showed that in the Mediterranean environment, the trace element content of unwashed lichen samples is greatly affected by soil contamination. However, despite the strong correlations between the concentrations of lithogene elements such as Al, Fe and Ti in P. sulcata, lichen levels of these elements were not at all linearly correlated with their concentrations in the soil, suggesting that dust contamination is highly variable and probably dependent on local site characteristics. All methods evaluated to minimize soil contamination indicated Cu, Pb and Zn as elements of atmospheric origin. However, while levels of Pb were similar to those reported for background areas, moderate pollution by Cu and Zn, probably from fertilizers used in agriculture, was revealed. For elements such as Cd and Mo, identified as atmophile, some uncertainty exists due to the fact that they are essential for lichen metabolism and accumulate intracellularly in lichens; they may therefore occur in soluble form in the lichen thallus.

Accumulation of heavy metals in epiphytic lichens near a municipal solid waste incinerator (central Italy).

The epiphytic lichen Parmelia caperata was usedas biomonitor in the area of a municipal solid wasteincinerator (Poggibonsi, central Italy) to investigatethe levels and the spatial distribution of the heavymetals Al, Cd, Cr, Cu, Fe, Hg, Pb and Zn. Levels ofAl, Cu and Hg were similar to those in unpollutedareas, whereas high values were found for Cr, Zn andespecially Cd. The distribution pattern of the lastthree metals and the exponential relationship of theirconcentrations with distance from the incinerator,showed that the disposal plant is a local source ofatmospheric pollution due to Cd, Cr and Zn. For thesemetals, long-term hazard should be seriously taken into account.

Effects of nutrient addition on species diversity and ground cover of “serpentine” vegetation

ABSTRACT Two nutrient addition experiments were carried out within a program of vegetation ecology of ultramafic soils in Tuscany, Italy. Nitrogen and especially phosphorus induced a slight increase in plant species richness and a significant increase in ground cover, but their interaction was not significant. The addition of nitrogen, phosphorus and potassium together greatly promoted ground cover and showed a partial effect in promoting species richness. The addition of calcium had the same effect on species richness, but did not affect ground cover or have any synergistic effect with nitrogen, phosphorus and potassium. Species composition was not significantly influenced by any of the treatments and the ground cover increases observed concerned species already growing in the plots. Availability of soil elements differed for calcium and potassium in the plots where they were added. The addition of calcium also reduced the availability of manganese, nickel and magnesium, as well as the Mg/Ca ratio, and i...

Periodicity, fluctuations and successions of macrofungi in fir forests (Abies alba Miller) in Tuscany, Italy

Abstract The present study, carried out in natural and planted Abies alba Miller woods, was undertaken as a contribution to knowledge of temporal changes occurring in fungal communities. Moreover, notes on fungal species and fungal communities in this type of wood are given. Correlations between meteorological variables and fungi (number of species and number of carpophores, as total or divided into trophic groups) were tested by Pearson’s product-moment coefficient. On a short time scale, weather parameters clearly play a major role, affecting periodicity and fluctuations; on a long time scale (10 years or more), correspondence analysis (CA) indicate that vegetation parameters and forest evolution affect successions.

Intranuclear crystalloids in leaves and styles of Linaria vulgaris mill

Unusual intranuclear inclusions present in the parenchymatic cells of leaves and styles of Linaria vulgaris are described. These inclusions are composed of layers of tubules spaced 9–10 nm apart. The direction of the tubules in each layer is offset 60° with respect to the tubular direction in the adjacent layers. The diameter of the tubules (23–26 nm) suggests a similarity to the cytoplasmic microtubules. The high degree of molecular order in these structures allows discrete optical diffraction to 7 nm. These intranuclear microtubular crystalloids, as already reported for other such crystalloids, have close associations with the nucleoli.

Relating spectral and species diversity through rarefaction curves

Rarefaction represents a powerful analytical approach in ecology for estimating the expected number of species within a given study area from local (α‐diversity) to regional (γ‐diversity) scales. From a landscape perspective, rarefaction curves are directly related to the environmental heterogeneity of the area sampled. The greater the landscape heterogeneity, the greater the expected species diversity. Therefore, remotely sensed images may potentially be used for predicting species diversity through the indirect method of analysing local spectral variation. The aim of this study was to test whether spectral variability can be used as a proxy for species diversity, from local to regional spatial scales. A total of 977 sampling units, each 50 m×50 m, were selected within the Asciano district (Central Italy) following a stratified random sampling. Each sampling unit was manually classified according to the first level of the Corine Land Cover classification legend. Data on plant species composition were collected in 10 m×10 m plots located within 98 random sampling units. The normalized difference vegetation index (NDVI) was calculated from a QuickBird image, and quantized into 8‐bit data (256 digital numbers, DNs) for building spectral rarefaction curves. Only those plots falling within the QuickBird image were used, which had the effect of reducing the thematic legend to two classes: crops and seminatural vegetation. Species and spectral rarefaction curves were then constructed for each land cover class. Rarefaction curves based on species and spectral properties showed similar results, that is a significantly different number of accumulated values given the same sampling effort for the two classes considered. The results of this study suggest that the shape of the spectral rarefaction curves may be an indirect indicator of environmental diversity, and thus may have potential for predicting biodiversity from local to landscape scales.

Pollen concentrations in central italy (ascoli piceno and siena)

Abstract Burkard volumetric samplers were used to carry out research on airborne pollen in the Ascoli Piceno and Siena atmosphere in the period April-September 1981. Total production in the period in question was quantitatively similar, with a prevalence of non-arboreal pollen in both stations. The overall trend has shown a positive correlation between the two stations. Differences were recorded with regard to the period of pollination and the quantity of pollen produced by Quercus, Poaceae, Oleaceae, Castanea, Plantaginaceae and Compositae.

Short-Term Changes of Response Indicators of Ecosystem Status in Broadleaved Forests in Tuscany (Central Italy)

The status of different response indicators of forest condition were measured and assessed between 1995 and 1997 at 6 Permanent Monitoring Plots (PMPs) in Tuscany (central Italy), where beech, holm oak and Turkey oak are the most frequent tree species. Foliage transparency, leaf damage and crown dieback have changed significantly over the monitoring period. Leaf area, length of the current year shoots, and total leaf area changed as well, but only for Turkey oak. Changes were consistent between and within the plots. Different indices of plant diversity showed marked changes, apparently linked to natural dynamics within individual ecosystems. These rapid and contrasting fluctuations in the various indicators of forest ecosystem make it difficult to derive a synthesis about the general condition of ecosystems and - especially - about the effects of air pollution.

INFLUENCE OF SALT CONTENT OF PLIOCENE CLAY SOIL ON THE EMERGENCE OF SIX GRASSES

ABSTRACT The effects of three soil salinity levels (450, 925, and 1150 μS/cm) on the emergence of six grasses from a clay badland area of central western Italy were investigated. The species were five annuals (Aegilops geniculata, Brachypodium distachyum, Hordeum maritimum, Parapholis incurva, and Parapholis strigosa) growing in the pioneer association Parapholido- Artemisietum cretaceae, and the perennial Bromus erectus, the dominant species of perennial grasslands. The tests were made in plastic pots filled with soils having different salt contents. A control, conducted in Petri dishes with distilled water, showed a high germination percentage for all species but different germination rates. In the soil tests, the emergence rate of all the species decreased with increasing soil salinity. Final emergence percentages were higher than 70% for all species and all salinities, except for P. incurva and P. strigosa (60 and 46.7%, respectively) at the highest salinity level. B. erectus showed the lowest emergen...