326 research outputs found
Effetti di stress ambientali sui processi fotochimici in Pinus halepensis Mill. analizzati mediante fluorescenza fogliare.
No full textEnvironmental parameters in relation to the response of Trifolium repens L. cv. Menna to ambient ozone
No full textEcophysiological characterization of Citrus sinensis (L.) Osbeck and relationships with type and amount of biogenic emissions
No full textIn this paper are shown the results obtained on Citrus sinensis (L.) Osbeck during the sampling campaigns performed in Burriana (Spain) in the frame of B.E.M.A. project. The daily trends of photosynthesis (A) showed higher values at morning and a decrement during the hottest hours of the day; for leaf transpiration (E) we observed a slight increment during the day. During different months (May '96, June '97 and July '95) we noted a progressive reduction in gas exchange of the leaves in relation to build-up of summer stress condition (-49% and -60% for June and July respect to May). In particular, net photosynthesis and leaf transpiration measured on Citrus leaves were, in general, characterised by low average values (2.7 +/- 0.06 (s.e.) mu mol CO2 m(-2)s(-1) and 0.665 +/- 0.021 (s.e.) mmol H2O m(-2)s(-1) for current leaves, respectively). The relationship between biogenic volatile organic compound (BVOC) emission rates normalised by assimilation (A) and gas exchange parameters as E/A ratio is reported. This latter is considered as an useful functional index to determine different vegetation types on a functional basis. We also found a good correlation between BVOC normalised emissions with air temperature. This behaviour has been reported for other species having monoterpene compounds in storage structures as Pinus species. Moreover, it is evident an uncoupling between BVOC emissions and photosynthesis. (C) 1999 Elsevier Science Ltd. All rights reserved
Annual estimations of ecophysiological parameters and biogenic volatile compounds (BVOCs) emissions in Citrus sinensis (L.) Osbeck
No full textChemical and physical interactions among trace gases (CH4, N2O, VOCs) contribute towards greenhouse effects. This paper by using a original simulation model analyses the annual trends of net photosynthesis, transpiration, and water use efficiency, the total primary production and finally the emission of monoterpenes from orange groves located in the Burriana plain (Spain). The net photosynthetic rate showed a bell-shaped trend with maximum average values of 3.5 mu molCO(2) m(-2) s(-1) calculated for the months of June and July. The canopy transpiration rate reached maximum values of approximately 2.5 mmolH(2)O m(-2) s(-1). Monoterpene emissions displayed a relevant increase during spring time reaching the highest values ol approximately 70 ng monoterpene m(-2) s(-1) during the summer period and a progressive decrease during the successive months. The loss of carbon by monoterpene emissions for the different plant organs is evaluated at approximately 0.404% of the total carbon fixed by photosynthesis (559.77 gC m(-2) y(-1)). On a fractionated basis the contribution of the leaves is 0.083% those of the fruits is 0.243% (for a period lasting from July to December), and only for the May period 0.079% for the flowers
René de Maulde, v.1880
No full textPortrait de René de Maulde (1852-?). Photographie Silli (13 quai Saint-Jean-Baptiste, Nice / boulevard National, Vichy), v.1880. Archives de Laprée, Quiestède, 5.P0103.16. Article révisé le 19/11/2019
Report on the preliminary B.E.M.A. measuring campaign at Castelporziano, Rome (Italy), June 1993.
No full textServizi Ecosistemici e ruolo del verde nella rimozione del particolato atmosferico in aree metropolitane
No full textLa vegetazione urbana fornisce importanti servizi ambientali di natura ricreativa, estetico-paesaggistica e non ultimo funzionale, migliorando il microclima e contribuendo a ridurre l’inquinamento atmosferico. Il particolato (PM) rappresenta uno degli inquinanti maggiormente diffusi e ad elevato impatto ambientale e sanitario con particolare riguardo in ambito metropolitano (Direttiva 2008/50/CE, e Rapporto WHO 2011). Numerosi studi hanno confermato l’effetto di mitigazione da parte della vegetazione sulle concentrazioni di inquinanti atmosferici, con sensibile miglioramento della qualità ambientale. I risultati presentati fanno parte di ricerche condotte sia in contesto urbano che periurbano, all’interno di una villa storica di Roma, Villa Ada, nei giardini del Museo di Storia Naturale della città di Milano e nell’ambito della foresta mediterranea nella Tenuta Presidenziale di Castelporziano (Roma). Obiettivo della ricerca è stato quello di quantificare in aree urbane e periurbane la rimozione di PM atmosferico, da parte del verde presente in differenti aree campione, caratterizzate da vegetazione arborea o erbacea e a differenti altezze lungo la chioma degli alberi nella foresta urbana mediterranea. I risultati hanno evidenziato un abbattimento delle concentrazioni di PM all’aumentare della densità della vegetazione presente, confermando l’effetto sinergico esercitato dalla copertura arborea e da quella arbustiva, le cosiddette green barrier. Gli studi in corso contribuiranno a chiarire il ruolo effettivo del verde, nelle differenti tipologie e strutture, nel mitigare l’inquinamento atmosferico in aree metropolitane
Urban ecosystem services: tree diversity and stability of PM10 removal in the metropolitan area of Rome
No full textUrban vegetation, and particularly urban forests, are known to provide important ecosystem services, such as urban air quality improvement by removing gaseous and particulate pollutants. The amount of PM10 removed by urban and periurban trees of the metropolitan area of Rome (evergreen broadleaves, deciduous broadleaves and conifers) was estimated by considering the minimum and maximum PM10 concentration values recorded in the Municipality of Rome during the years 2003 and 2004. The results of these simulations have been used to map the Ecosystem Service of PM10 removal by the three functional groups in the five Sanitary Districts of the Municipality. Given the spatial uniformity of PM10 levels in the urban area, the highest amount of PM10 deposition rates, during the whole period, are those of the Sanitary District with the largest vegetation cover (RMD). It is also interesting to highlight that the highest deposition fluxes, for the three functional groups, were estimated for the 2004 summer period, in concurrence with the highest mean values of Leaf Area Index. Our results confirm the crucial role of vegetation in supporting significant Ecosystem Services as air quality improvement, highlighting the importance of biodiversity and green infrastructures of sustain and enhance benefits provided by trees
Valutazione dell'effetto combinato di stress ossidativi in un ecosistema costiero: efficienza funzionale e mantenimento dei servizi ecosistemici.
No full textGli ecosistemi costieri a macchia mediterranea sono soggetti a numerosi fattori di stress ossidativi che costitutivamente insistono in queste aree come la salinità al suolo che può aumentare a causa dell’eccessivo emungimento della falda e del conseguente avanzamento del cuneo salino. La crescente espansione dei centri urbani in prossimità delle aree di costa, largamente sfruttate per motivi economici e ricreativi, sta determinando un aumento dell’esposizione della vegetazione a inquinanti ad azione fitotossica come l’ozono troposferico, soprattutto nel periodo estivo in cui le condizioni ambientali sono già limitanti. L’attività di ricerca è stata svolta in due siti a diversa distanza dalla linea di costa, in un’area protetta del litorale laziale (Tenuta Presidenziale di Castelporziano) integrando misure eco-fisiologiche a livello fogliare, studi strutturali (rapporto area fogliare e area conduttrice) ed elementari (contenuto in azoto e cloro all’interno delle foglie). Descrivere come tratti funzionali e strutturali cambiano in un ecosistema costiero e come l’interazione tra stress ossidativi può condizionare le strategie di adattamento di specie della macchia mediterranea, può contribuire ad individuare eventuali marcatori precoci di stress. Inoltre l’integrazione di dati relativi a differenti caratteri morfo-funzionali può contribuire a mettere in risalto quanto l’efficienza funzionale della vegetazione costiera e l’integrità dei servizi ecosistemici che essa garantisce, siano legate
A chamber fumigation study to evaluate the performance of the snap bean biomonitoring system under simulated Mediterranean climatic conditions.
No full textThe O3 biomonitoring system based on sensitive (S156) and resistant (R123) genotypes of
snap bean (Phaseolus vulgaris L.) (Burkey et al. 2005), is being field-tested under the ICP
Vegetation since 2008. Although OTCs studies have found clear relationships between O3
exposure, physiological parameters, leaf injury, and yield of the S156/R123 system (Flowers
et al., 2007), some biased results have emerged during field campaigns carried out in southern
Europe. In a chamber fumigation experiment, we have tested the performance of the snap bean
system under simulated Mediterranean microclimatic conditions. Sixteen seeds per genotype
were grown in 12 l pots inside a walk-in chamber (mean day/night T: 28.2/24.0 °C; RH: 60%;
leaf-level PAR: 350 E m-2s-1; Photoperiod: 8:00-19:00 h; daily irrigation at field capacity);
after the development of the 2nd trifoliate leaf, eight plants per genotype were transferred in a
twin chamber under the same conditions, and fumigated 7 hours per day with 80 ppb of O3 for
20 days, for a POD6 of 4.7 mmol m-2 and 3.0 mmol m-2 for S and R, respectively. In the
fumigated chamber, both genotypes showed visual O3 symptoms (ICP Vegetation
Experimental Protocol 2011). However, symptoms appeared earlier on the S plants, and were
more severe at the end of the experiment than in the R plants (Fig. 1). Net photosynthesis (Pn)
and stomatal conductance (gs) were significantly reduced in both cultivars (Pn: -43.4% and -
54.1%; gs: -42.8% and -31.6% than the control for S and R, respectively), with no difference
between S and R at the end of the fumigation. Interestingly, despite the Pn reduction, the total
photosynthetic Performance Index (PItot, Strasser et al., 2010) increased significantly in the
fumigated S plants since the onset of flowering, suggesting the triggering of detoxification
processes (Bussotti et al., 2011; Mereu et al., 2011). The final pod harvest showed that,
although a significant O3-induced reduction of pod yield was evident in both genotypes, the
S/R total pod weight ratio was lower than 1 both in the control and in the fumigated sets (0.63
and 0.57, respectively). In conclusion, our data suggests that, although prudence is needed in
generalizing the results obtained in
closed chambers, further studies are
required to clarify the O3 response of
the S156/R123 system before its
application in the field, particularly
under Mediterranean climatic
conditions
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