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San Michele all'Adige, Italy

Di Baccio D.,SantAnna School of Advanced Studies | Castagna A.,University of Pisa | Tognetti R.,University of Molise | Tognetti R.,The Project Center on Mountain Forests | And 2 more authors.
Journal of Plant Physiology | Year: 2014

Soil cadmium (Cd) contamination is becoming a matter of great global concern. The identification of plants differentially sensitive to Cd excess is of interest for the selection of genotype adaptive to grow and develop in polluted areas and capable of ameliorating or reducing the negative environmental effects of this toxic metal. The two poplar clones I-214 (Populus×canadensis) and Eridano (Populus deltoides×maximowiczii) are, respectively, tolerant and sensitive to ozone (O3) exposure. Because stress tolerance is mediated by an array of overlapping defence mechanisms, we tested the hypothesis that these two clones differently sensitive to O3 stress factor also exhibit different tolerance to Cd. With this purpose, an outdoor pot experiment was designed to study the responses of I-214 and Eridano to the distribution of different Cd solutions enriched with CdCl2 (0, 50 and 150μM) for 35 days. Changes in leaf area, biomass allocation and Cd uptake, photosynthesis, chlorophyll fluorescence, leaf concentration of nutrients and pigments, hydrogen peroxide (H2O2) and nitric oxide (NO) production and thiol compounds were investigated. The two poplar clones showed similar sensitivity to excess Cd in terms of biomass production, photosynthesis activity and Cd accumulation, though physiological and biochemical traits revealed different defence strategies. In particular, Eridano maintained in any Cd treatment the number of its constitutively wider blade leaves, while the number of I-214 leaves (with lower size) was reduced. H2O2 increased 4.5- and 13-fold in I-214 leaves after the lowest (L) and highest (H) Cd treatments, respectively, revealing the induction of oxidative burst. NO, constitutively higher in I-214 than Eridano, progressively increased in both clones with the enhancement of Cd concentration in the substrate. I-214 showed a more elevated antioxidative capacity (GSH/GSSG) and higher photochemical efficiency of PSII (Fv/Fm) and de-epoxidation degree of xantophylls-cycle (DEPS). The glutathione pool was not affected by Cd treatment in both clones, while non-protein thiols and phytochelatins were reduced at L Cd treatment in I-214. Overall, these two clones presented high adaptability to Cd stress and are both suitable to develop and growth in environments contaminated with this metal, thus being promising for their potential use in phytoremediation programmes. © 2014 Elsevier GmbH.

Castagna A.,University of Pisa | Di Baccio D.,SantAnna School of Advanced Studies | Di Baccio D.,National Research Council Italy | Ranieri A.M.,University of Pisa | And 3 more authors.
Environmental Science and Pollution Research | Year: 2014

Information on plant responses to combined stresses such as ozone (O3) and cadmium (Cd) is scarce in tree species. On the other hand, high O3 concentrations in the atmosphere and heavy metal contaminations in water and soil simultaneously affect forest ecosystems. Toxic metals may exacerbate the consequences of air pollutants. In this research, two poplar clones, differently sensitive to O3 ("I-214" O3-tolerant and "Eridano" O3-sensitive), were grown for 5 weeks in pots supplied with 0 and 150 mg Cd kg-1 soil and then exposed to a 15-day O3 fumigation (60 nl l-1, 5 h a day) or supplied with charcoal-filtered air under the same conditions (referred to as control samples). The effects of the two stressors, alone or in combination, on Cd accumulation, photosynthetic capacity, ethylene emission and oxidative state were investigated in fully expanded leaves. Cadmium accumulation in leaves caused a reduction, but not complete failure, of photosynthesis in Eridano and I-214 poplar clones. The reduction in assimilation rate was more important following O3 fumigation. Stomatal aperture after O3 treatment, instead, increased in I-214 and decreased in Eridano. Overall, Cd treatment was effective in decreasing ethylene emission, whereas O3 fumigation increased it in both clones, although interacting with the metal treatment. Again, O3 fumigation induced a significant increase in ascorbate (ASA) + dehydroascorbate (DHA) content, which was strongly oxidised by O3, thus decreasing the redox state. On the other hand, Cd treatment had a positive effect on ASA content and redox state in I-214, but not in Eridano. Although Cd and O3 are known to share some common toxicity pathways, the combined effects induced distinct clone-specific responses, underlying the complexity of plant reactions to multiple stresses. © 2014 Springer-Verlag Berlin Heidelberg.

Zorer R.,Research and Innovation Center | Eccel E.,Research and Innovation Center | Tognetti R.,University of Molise | Tognetti R.,The Project Center on Mountain Forests | And 2 more authors.
Italian Journal of Agrometeorology | Year: 2014

The Italian cypress (Cupressus sempervirens L.) is widespread in the entire Mediterranean region and reaches in the Province of Trento high latitude (46° 21′ North) and elevation (about 985 m a.s.l.). The human range expansion of this cypress has taken place at the Northern margin of the range in Italy in recent decades, driven by ornamental planting in spite of climatic constraints imposed by low temperature. The aim of the present work was to investigate the effect of low temperature in cypress in a nursery of the Autonomous Province of Trento (North-Eastern Italy). Over a period of two and half years, maximum quantum use efficiency of photosystem II (FV/FM) was monitored in order to study the effects of air temperature on the photosynthetic efficiency of 99 different clones and to derive information about the potential distribution of cypress in this province. A significant positive correlation (r = 0.64, p < 0.001) was found between air temperature and FV/FM over the 29- month period and especially in spring and autumn. Minimum values of FV/FM were observed in winter. Moreover, in order to assess critical environmental factors for cypress, mean values of FV/FM were correlated with daily air temperature and temperature-based indices to identify the driving factors of the physiological changes along the annual cycle. The maximum value of correlation (r = -0.85, p < 0.001) was found with 10-day Cold Degree-Day Running Sums before sampling and with a threshold of 2.0 °C for daily minimum air temperature.

Cocozza C.,University of Molise | Vitullo D.,University of Molise | Lima G.,University of Molise | Maiuro L.,University of Molise | And 3 more authors.
Environmental Science and Pollution Research | Year: 2014

The plant-microorganism combinations may contribute to the success of phytoextraction of heavy metal-polluted soil. The purpose of this study was to investigate the effects of cadmium (Cd) soil concentration on selected physiological parameters of the poplar clone "I-214" inoculated at root level with a strain (BT4) of Pseudomonas fluorescens and a commercial product based on microbial consortia (Micosat F Fito®). Plants were subjected to Cd treatment of 40 mg kg-1 in greenhouse. The effects of plant-microbe interactions, plant growth, leaf physiology, and microbial activity were periodically monitored. Metal concentration and translocation factors in plant tissues proved enhanced Cd uptake in roots of plants inoculated with P. fluorescens and transfer to shoots in plants inoculated with Micosat F Fito®, suggesting a promising strategy for using microbes in support of Cd uptake. Plant-microbe integration increased total removal of Cd, without interfering with plant growth, while improving the photosynthetic capacity. Two major mechanisms of metal phytoextraction inducted by microbial inoculation may be suggested: improved Cd accumulation in roots inoculated with P. fluorescens, implying phytostabilization prospective and high Cd transfer to shoots of inoculated plants, outlining enhanced metal translocation. © 2013 Springer-Verlag Berlin Heidelberg.

Maselli F.,CNR Institute for Biometeorology | Cherubini P.,Swiss Federal Institute of forest | Chiesi M.,CNR Institute for Biometeorology | Gilabert M.A.,University of Valencia | And 5 more authors.
Agricultural and Forest Meteorology | Year: 2014

Recent investigations have highlighted the dependence of Mediterranean forest production on spring rainfall. The current work introduces the concept of the start of the dry season (SDS) and performs a three-step analysis to determine the effect of SDS on Mediterranean forest production. Seven forest zones of Tuscany (Central Italy), which present differently pronounced Mediterranean features, are considered. First, a statistical analysis investigates the influence of spring water budget on forest Normalized Difference Vegetation Index (NDVI) inter-annual variations during July-August. The analysis is then extended to assess the impact of inter-annual SDS variability on forest gross primary production (GPP) simulated by a NDVI driven parametric model, modified C-Fix. These simulations lead to rank the considered forest types according to the relevance of SDS in regulating inter-annual GPP variations. The application of similar statistical analyses to detrended tree ring-width time series of typical Tuscany forests confirms the existence of an eco-climatic gradient in the functional relevance of SDS. The influence of SDS on tree growth is attenuated moving from Mediterranean arid to temperate humid environments. These findings are examined and interpreted from an eco-physiological viewpoint taking into consideration the peculiarity of Mediterranean forest ecosystems. Next, relevant implications are discussed in view of the possible consequences of ongoing climate change. © 2014 Elsevier B.V.

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