[Show abstract][Hide abstract] ABSTRACT: Poplar is promising for phytoremediation and a large phenotypic variation in response to Cd has been observed among and within Populus species. Scientific knowledge has increased regarding the physiological and molecular mechanisms of Cd response in poplars, however its genetic basis is still poorly understood. This study, investigated the genetic architecture of Cd accumulation and tolerance in Populus nigra L. A F1 progeny, grown in hydroponics under Cd treatment and control conditions, was analyzed by 21 phenotypic traits related to Cd tolerance, Cd accumulation, and chlorophyll fluorescence. These traits present a broad-sense heritability ranging from 0.22 to 0.57. Mapping of quantitative trait loci (QTL) revealed a total of
36 QTL for the female map and 21 QTL for the male map, corresponding to 12 and 11 genomic regions, respectively. The phenotypic variance explained by QTL ranged from 6.2 to 28.7 %, with an average of 14.5 %. Three main QTL cluster regions were defined on chromosomes IV and XIV. The projection of QTL intervals on the Populus trichocarpa Torr. & Gray annotated genome identified positional candidate genes (CGs), functionally related to the regulation of transcription, transport, response to oxidative stress, and the glutathione pathway. It was found that some CGs are directly related to Cd transport and detoxification, whereas other nonmetal-specific CGs could also contribute to explain the phenotypic variation in Cd accumulation and tolerance. The high accumulation of Cd in roots and the relatively low translocation in leaves suggest that P. nigra would be a good candidate for the phytoremediation of metal-polluted sites.
Trees 01/2015; DOI:10.1007/s00468-015-1281-5 · 1.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We estimated water-use efficiency and potential photosynthetic assimilation of Holm oak (Quercus ilex L.) on slopes of NW and SW aspects in a replicated field test examining the effects of intensifying drought in two Mediterranean coppice forests. We used standard techniques for quantifying gas exchange and carbon isotopes in leaves and analyzed total chlorophyll, carotenoids and nitrogen in leaves collected from Mediterranean forests managed under the coppice system. We postulated that responses to drought of coppiced trees would lead to differential responses in physiological traits and that these traits could be used by foresters to adapt to predicted warming and drying in the Mediterranean area. We observed physiological responses of the coppiced trees that suggested acclimation in photosynthetic potential and water-use efficiency: (i) a significant reduction in stomatal conductance (P<0.01) was recorded as the drought increased at the SW site; (ii) foliar 13C increased as drought increased at the SW site (P<0.01); (iii) variations in levels of carotenoids and foliar nitrogen, and differences in foliar morphology were recorded, and were tentatively attributed to variation in photosynthetic assimilation between sites. These findings increase knowledge of the capacity for acclimation of managed forests in the Mediterranean region of Europe.
Journal of Forestry Research 11/2014; 25(4):839-845. DOI:10.1007/s11676-014-0532-4 · 0.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Building research capacity in forest science has been recognized internationally as important in order to produce a sound evidence basis for decision-making in policy and practice, even if there is currently little evidence on how to measure and consequently spread progress and innovations resulting from forest research, especially in a fragmented region such as the Mediterranean.
The paper aims at establishing a framework from 79 institutions undertaking forest research across thirteen Mediterranean countries for measuring their research capacities and the potential they reached to disseminate results and innovations in forest research. The methodology adopted makes use of common indicators thereby allowing comparisons across countries as regards the following: (i) research lines performed in forest research, (ii) budget generated by forest projects, (iii) overall full budget spent for forest research, (iv) number of forest projects implemented, (v) number of total researchers, permanent staff and non-permanent staff deployed in forest research, and (vi) ISI papers published in forest subjects.
Forest research capacities have tentatively been clustered to find similarities or dissimilarities across countries, in order to identify possible partnerships to be reached and to highlight causal indicators that affected the clustering.
The paper findings contribute to address how capacity for forest research in the Mediterranean area is developed and how to measure and evaluate the performances of research and innovation systems. They provided further contributions to existing debates in the literature in order to foster research collaboration in the forest sector, knowledge mobilization, innovation and proposals/policies for a common research framework in the European forest sector.
Forest Policy and Economics 10/2014; DOI:10.1016/j.forpol.2014.08.003 · 1.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ozone flux estimates from the i-Tree model were compared with ozone flux measurements using the Eddy Covariance technique in a periurban Mediterranean forest near Rome (Castelporziano). For the first time i-Tree model outputs were compared with field measurements in relation to dry deposition estimates. Results showed generally a good agreement between predicted and measured ozone fluxes (least sum square = 5.6 e(-4)) especially when cumulative values over the whole measurement campaign are considered. However at daily and hourly time-step some overestimations were observed in estimated values especially in hot dry periods. The use of different m values in the Ball-Berry formula in the different periods, produced the best fit between predicted and measured ozone fluxes. This suggests that a variable value for the coefficient m accounting for water availability may be appropriate to improve model estimates for Mediterranean and drought prone regions.
[Show abstract][Hide abstract] ABSTRACT: The world is shifting to an innovation economy and forest biotechnology can play a major role in the bio-economy by providing farmers, producers, and consumers with tools that can better advance this transition. First-generation or conventional biofuels are primarily produced from food crops and are therefore limited in their ability to meet challenges for petroleum-product substitution and climate change mitigation, and to overcome the food-versus-fuel dilemma. In the longer term, forest lignocellulosic biomass will provide a unique renewable resource for large-scale production of bioenergy, biofuels and bio-products. These second-generation or advanced biofuels and bio-products have also the potential to avoid many of the issues facing the fi rst-generation biofuels, particularly the competition concerning land and water used for food production. To expand the range of natural biological resources the rapidly evolving tools of biotechnology can ameliorate the conversion process, lower the conversion costs and also enhance target yield of forest biomass feedstock and the product of interest. Therefore, linking forest biotechnology with industrial biotechnology presents a promising approach to convert woody lignocellulosic biomass into biofuels and bio-products. Major advances and applications of forest biotechnology that are being achieved to competitively position forest biomass feedstocks with corn and other food crops are outlined. Finally, recommendations for future work are discussed.
Research and innovation in sustainable forestry to advance competitive global bioeconomy, Arezzo; 07/2014
[Show abstract][Hide abstract] ABSTRACT: The countries of the Mediterranean basin, as well as those of other Mediterranean Climate Areas, face similar challenges regarding the sustainability of forest ecosystems and the delivery of crucial goods and services that they provide in a context of rapid global changes. Advancing scientific knowledge and fostering innovation is essential to ensure the sustainable management of Mediterranean forests and maximise the potential role of their unique goods and services in building a knowledge-based bioeconomy in the region. In this context, FORESTERRA project (Enhancing FOrest RESearch in the MediTERRAnean through improved coordination and integration), aims at reinforcing the scientific cooperation on Mediterranean forests through an ambitious transnational framework to reduce the existing research fragmentation and maximise the impact of research activities puts the basis for: i) better coordination between partners’ forest research programmes; ii) in-depth and durable cooperation and integration among FORESTERRA partners (enhancing the scientific links between the northern and southern Mediterranean sub-regions); iii) long term contribution to structuring the European Research Area.
XVI Convegno AIAM 2013 - "Agrometeorologia per la sicurezza ambientale ed alimentare" published by Italian Journal of Agrometeorology, Firenze; 06/2013
[Show abstract][Hide abstract] ABSTRACT: The countries of the Mediterranean basin face several challenges regarding the sustainability of forest ecosystems and the delivery of crucial goods and services that they provide in a context of rapid global changes. Advancing scientific knowledge and foresting innovation is essential to ensure the sustainable management of Mediterranean forests and maximize the potential role of their unique goods and services in building a knowledge-based bioeconomy in the region. In this context, the European project FORESTERRA ("Enhancing FOrest RESearch in the MediTERRAnean through improved coordination and integration”) aims at reinforcing the scientific cooperation on Mediterranean forests through an ambitious transnational framework in order to reduce the existing research fragmentation and maximize the effectiveness of forest research activities. Within the FORESTERRA project framework, this work analyzed the infrastructures equipment of the Mediterranean countries belonging to the project Consortium. According to the European Commission, research infrastructures are facilities, resources and services that are used by the scientific communities to conduct research and foster innovation. To the best of our knowledge, the equipment and availability of infrastructures, in terms of experimental sites, research facilities and databases, have only rarely been explored. The aim of this paper was hence to identify complementarities, gaps and overlaps among the different forest research institutes in order to create a scientific network, optimize the resources and trigger collaborations.
[Show abstract][Hide abstract] ABSTRACT: The Mediterranean Region is defined according to its biogeography and bioclimate. Climate is characterized by mild winters and hot, dry summer. Biodiversity is rich and landscape patterns are complex. Mediterranean forests have historically been subjected to numerous threats (forest fires, over-exploitation, deforestation, degradation), that are today accentuated under climate and land use changes. In this respect, the Mediterranean area appears among the most vulnerable areas to global change. Forest area in the region has increased by 10% between 1990 and 2000. Roundwood nowadays represents 60% and woodfuel 40% of total wood products (125 Mm3). Sometime non-wood forest products and services are more important as they represent 60–70% of total economic value (133 € ha−1) of Mediterranean forests. There are already evidences of impacts of recent climate change on ecophysiology, productivity, dieback and distribution of Mediterranean forests and these impacts will become worse in the future, particularly for increased evaporative demand and repeated extreme events. An interdisciplinary research agenda, integrated with monitoring networks and projection models is needed to provide information at all levels of decision making and to implement a framework of dynamic and adaptive management planning.
Regional Assessment of Climate Change in the Mediterranean, 01/2013: pages 71-100;
[Show abstract][Hide abstract] ABSTRACT: Mediterranean forests close to urban areas are exposed to polluted plumes loaded with tropospheric ozone. This is the case of Castelporziano Estate, a 6000 ha Mediterranean forest 25 km from Rome downtown on the coast of the Mediterranean Sea. In September 2011 we started an intensive field campaign aimed at investigating ozone deposition from a mixed Mediterranean forest, mainly composed by Quercus suber, Quercus ilex, Pinus pinea. Measurements at canopy level with the eddy covariance technique were supported by a vegetation survey and the measurement of all environmental parameters which allowed to calculate stomatal ozone fluxes. Leaf-level measurements were used to parameterize models to calculate stomatal conductance based on a Jarvis-type and Ball-Berry approach. We show changes in magnitude of ozone fluxes from a warm (September) to a cold period (October December). Stomatal component explained almost the totality of ozone fluxes during the cold days, but contributed only up to 50% to total ozone deposition during warm days, suggesting that other sinks (e.g. chemistry in the gas-phase) play a major role. Modeled stomatal ozone fluxes based on a Jarvis-type approach (DO3SE) correlated with measured fluxes better than using a Ball-Berry approach. A third model based on a modified Ball-Berry equation was proposed to account for the non-linear dependency of stomatal conductance on relative humidity. This research will help the development of metrics for ozone-risk assessment and advance our understanding of mixed Mediterranean forests in biosphere atmosphere exchange.
[Show abstract][Hide abstract] ABSTRACT: River systems are subjected to continuous physical changes as a result of their sediment transport. River dynamics is mainly determined by the seasonal variation of weather conditions and, together with the nature of the catchment and land management, affects flow patterns on a local scale. Riparian vegetation is well adapted to this periodical disturbance. It naturally regenerates on the new mineral soil created by the redistribution of river sediments during floods, playing an important role in the maintenance of streams and riverbanks stability. The high level of resilience and productivity of riparian tree species like Populus, contributes to the rapid biomass accumulation of riparian vegetation making these ecosystems of potential interest for biomass production for energy. This paper presents an operational methodology for investigating the biomass potential from riparian forests by coupling airborne laser scanning data and field survey. A case study on assessing and mapping biomass dynamics over a seventeen year period along a tract on the Paglia river, in Central Italy, is presented and discussed. The results highlight that the surface of the poplar-dominated riparian vegetation has significantly changed over the 1989–2006 period. More than 70 ha of new poplar forest were naturally regenerated during the analyzed period. The total amount of aboveground woody biomass of the riparian forest at the second inventory occasion has been estimated in 88 Mg ha−1, evidencing a large amount of technically available resources for bioenergy production (around 80% of the standing woody biomass). The innovative strategy here proposed to assess and map at a very high spatial resolution the aboveground woody biomass of riparian forest meets the monitoring requirements to support energy production based on modern, non-conventional biomass harvest planning options.
Biomass and Bioenergy 01/2012; 54. DOI:10.1016/j.biombioe.2012.10.023 · 3.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In light of impending water and arable land shortages, population growth and climate change, it is more important than ever to examine how forest tree domestication can be accelerated to sustainably meet future demands for wood, biomass, paper, fuel and biomaterials. Because of long breeding cycles, tree domestication cannot be rapidly achieved through traditional genetic improvement methods alone. Integrating modern genetic and genomic techniques with conventional breeding will expedite tree domestication. Breeders will only embrace these technologies if they are cost-effective and readily accessible, and forest landowners will only adopt end-products that meet with regulatory approval and public acceptance. All parties involved must work together to achieve these objectives for the benefit of society.
[Show abstract][Hide abstract] ABSTRACT: Carefully managed tree plantations offer an opportunity for sustainable biomass production. In recent years, the responses of the Salicaceae to environmental constraints have increasingly been investigated at different levels of biological integration, giving rise to a physiological approach to the function of trees in environmental restoration and monitoring. Significant progress has been achieved by the poplar and willow community in understanding targeted characteristics of complex tree stress responses. The Fifth International Poplar Symposium brought together experts in this area, with the main objective being to improve, coordinate and communicate existing national research on the biological and environmental dimension of multifunctional poplar and willow plantations. The secondary objective was to develop a network of research scientists and extension workers to provide scientific support for subjects interested in using fast-growing poplar and willow species for tree-related environmental projects. The ultimate goal was to build up services for the multipurpose tree plantation network on local-level management in order to obtain maximized benefits from tree crops. The purpose was also to maximize the synergy between local knowledge and global-level processes that require information on multipurpose tree crop production.
Tree Physiology 12/2011; 31(12):1289-92. DOI:10.1093/treephys/tpr117 · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Little is known about the variability of response to heavy metal stress within tree species, although it could be a key for a better understanding of tolerance mechanisms and for breeding. The aim of the present study was to characterize the natural variation of response to cadmium (Cd) in Populus nigra L. in order to understand the mechanisms of Cd tolerance. For that, two P. nigra genotypes, originating from contrasting environments in northern (genotype 58-861) and southern (genotype Poli) Italy, were exposed to Cd stress in hydroponics for 3 weeks. The effect of stress was estimated by measuring biomass production, photosynthetic performance and accumulation and translocation of Cd at the end of the experiment. To better understand the mechanisms of Cd tolerance, the expression of some candidate genes involved in the ascorbate-glutathione cycle (ascorbate peroxidase, glutathione reductase, glutathione S-transferase) and in metal sequestration (metallothioneins) was analyzed in leaves. Biomass production and photosynthesis were affected by the treatment in both clones but the southern clone was markedly more tolerant to Cd stress than the other. Nevertheless, the Cd content in leaves was not significantly different between the two clones and was quite low compared to other species. The content of thiols and phytochelatins (PCs), associated with the transcription profile of the glutathione S-transferase gene, indicated relevant differences in the use of the PCs pathway under Cd stress, which could explain the different tolerance to Cd. The northern clone accumulated thiols but down-regulated the GST gene, whereas the southern clone accumulated PCs and up-regulated the GST gene, which can be useful to complex and detoxify Cd. These results suggest that the glutathione pathway is involved in the differential Cd tolerance of the two genotypes. The natural germplasm of P. nigra represents a valuable resource for understanding tolerance to Cd and for selection of plant material for phytoremediation.
Tree Physiology 09/2011; 31(12):1309-18. DOI:10.1093/treephys/tpr088 · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Soil salinity is an important limiting factor to tree growth and productivity. Populus alba L. is a moderately salt-tolerant species and its natural populations are adapted to contrasting environments, thus providing genetic resources to identify key genes for tolerance to abiotic stress, such as salinity. To elucidate the molecular and genetic basis of variation for salinity tolerance in P. alba, we analyzed the short-term ecophysiological and transcriptome response to salinity. Two contrasting genotypes, 6K3, salt sensitive, and 14P11, salt tolerant, originating from North and South Italy, respectively, were challenged with salt stress (200 mM NaCl). Sodium accumulated in the leaves of salt-treated plants and its concentration increased with time. The net photosynthesis was strongly reduced by salinity in both genotypes, with 6K3 being significantly more affected than 14P11. The transcriptional changes in leaves were analyzed using cDNA microarrays containing about 7000 stress-related poplar expressed sequence tags (EST). A microarray experiment based on RNA pooling showed a number of salinity--regulated transcripts that markedly increased from 3 h to 3 days of salinity treatment. Thus, a detailed analysis was performed on replicated plants collected at 3 days, when ~20% of transcripts showed significant change induced by salinity. In 6K3, there were more genes with decreased expression than genes with increased expression, whereas such a difference was not found in 14P11. Most transcripts with decreased expression were shared between the two genotypes, whereas transcripts with increased expression were mostly regulated in a genotype-specific manner. The commonly decreased transcripts (71 genes) were functionally related to carbohydrate metabolism, energy metabolism and photosynthesis. These biological processes were consistent with the strong inhibition of photosynthesis, caused by salinity. The commonly increased transcripts (13 genes) were functionally related to primary metabolism and biosynthesis of proteins and macromolecules. The salinity-increased transcripts discriminated the molecular response of the two genotypes. In 14P11, the 21 genes specifically salinity-induced were related to stress response, cell development, cell death and catabolism. In 6K3, the 15 genes with salinity-increased expression were involved in protein biosynthesis, metabolism of macromolecules and cell organization and biogenesis. The difference in transcriptome response between the two genotypes could address the molecular basis of intra-specific variation of salinity tolerance in P. alba.
Tree Physiology 09/2011; 31(12):1335-55. DOI:10.1093/treephys/tpr083 · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, the genes of the Aux/IAA family were used as functional markers to characterise bud break stages in a white poplar clone. In the first experiment, under greenhouse conditions, the sprouting of repressed sylleptic buds was obtained by pruning the shoot tip during growing season. Buds were collected at 0, 6, 24 and 48 h after pruning for molecular analyses. A decrease in transcript level of IAA4 and IAA8 genes was observed in the first and second bud below the cut after 6 and 24 h, respectively. In the second experiment, bud break of post-dormant proleptic buds was induced by forcing in climatic chamber. The first 6 and the following 6 buds below the apical one were sampled every 48 h during forcing. Anatomical studies were also carried out on buds and plants were equipped with stem and bud radial growth sensors to check their swelling. In both experiments, gene expression patterns showed a decrease and a successive increase in expression of IAA4 and IAA8 genes during bud break. The transient down-regulation of these genes was observed only in buds that formed new branches. Thus, similar molecular mechanisms are involved in bud break of both sylleptic and proleptic buds.
[Show abstract][Hide abstract] ABSTRACT: Rooted cuttings of Populus nigra L. clone Poli and Salix alba L. clone SS5 were treated for three weeks with 50 μM CdSO4 in nutrient solution. The willow showed a far higher Cd tolerance, expressed as tolerance index (Ti), than the poplar in
both roots and leaves. The root Cd content was higher in poplar than in willow, whereas in leaves the opposite was found.
As a consequence, the translocation factor (Tf) revealed a greater ability of Cd transport in willow than in poplar. Cd treatment
enhanced cysteine, γ-glutamylcysteine and reduced glutathione contents in roots of both species, whereas in leaves they were
only enhanced in poplar. Furthermore, only poplar leaves showed an enhanced content of phytochelatins, whereas malic and citric
acids rose in response to Cd only in the willow leaves. Cd treatment increased putrescine, spermidine and spermine contents
in both roots and leaves of the willow, whereas in poplar only the putrescine content was enhanced in roots.
Additional key wordscitric acid–cysteine–malic acid–phytochelatins–polyamines–poplar–thiols–translocation factor–willow
Biologia Plantarum 06/2011; 55(2):383-386. DOI:10.1007/s10535-011-0060-4 · 1.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effect of salt stress on leaf morphology and functionality was studied in three Populus alba genotypes differing in tolerance to salinity: 6K3 (sensitive), 2AS11 (moderately tolerant), and 14P11 (tolerant). Plants were subjected to an intense and progressive salt stress from 50 to 250 mM NaCl by 50 mM steps at 10-day intervals. The micromorphological results highlighted phenotypic variation among the three genotypes already in control plants, with the genotype 14P11 having significantly smaller epidermal cells and higher stomatal density. Salt-treated plants modulated differently the expansion of stomata compared with epidermal cells. Regression analysis showed significant correlations between decrease of stomatal area and stomatal conductance (gs) in genotypes 14P11 and 6K3. So, the common reduction of stomatal area could be an early mechanism to save water in this species. However, only genotype 14P11 showed further significant decrease of this trait under the highest salinity level, combined with a significant reduction in leaf length. In addition, this genotype showed the lowest leaf abscission rate at the end of salt stress period. The genotype 6K3 was severely affected by leaf necrosis and showed the highest leaf abscission rate in salt stress conditions. In the moderately tolerant genotype 2AS11, an intermediate plastic behaviour in both leaf morphology and physiology was observed during the experiment. The phenotypic variation among the three genotypes in terms of micromorphology and stomatal conductance is discussed in relation to plant functionality in salt stress conditions. Overall results suggest that leaf morphological habit contributes to salt tolerance in P. alba.