Letteratura scientifica selezionata sul tema "Foliage emissions"
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Articoli di riviste sul tema "Foliage emissions"
1
Bunce, Hubert W. F. "Empirical estimates of loss of value in a second growth coniferous forest related to changes in fluoride emissions". Forestry Chronicle 69, n. 1 (1 febbraio 1993): 71–74. http://dx.doi.org/10.5558/tfc69071-1.
Testo completoAbstract (sommario):
Empirical values for western hemlock in a forest surrounding an aluminum smelter are given. A reduced rate of growth loss is suggested to relate to a reduction in the level of emission of fluoride from the smelter. From 1971 to 1980, the trees showed reduced growth when emissions were 3.7 tonnes per day and the foliage fluoride content was 74 parts per million (ppm). An emission level of 1.4 tonnes/day produced foliage containing 19 ppm fluoride and no height growth reduction. From 1972 to 1981, 2.6 years of growth on 895 hectares were estimated to be lost which were equal to 26 993 cubic metres (m3) with a value of $18,000/yr. (1986 dollars). Key words: Growth reduction, value loss, second growth, western hemlock, air emissions, fluoride, aluminum smelter, British Columbia
2
Aalto, J., P. Kolari, P. Hari, V. M. Kerminen, P. Schiestl-Aalto, H. Aaltonen, J. Levula, E. Siivola, M. Kulmala e J. Bäck. "New foliage growth is a significant, unaccounted source for volatiles in boreal evergreen forests". Biogeosciences Discussions 10, n. 11 (21 novembre 2013): 18121–50. http://dx.doi.org/10.5194/bgd-10-18121-2013.
Testo completoAbstract (sommario):
Abstract. Estimates of volatile organic compound (VOC) emissions from forests are based on the assumption that foliage has a steady emission potential over its lifetime, and that emissions are mainly modified by short term variations in light and temperature. However, in many field studies this has been challenged, and high emissions and atmospheric concentrations have been measured during periods of low biological activity such as in springtime. We conducted measurements during three years, using an online gas-exchange monitoring system to observe volatile organic emissions from a mature (1 yr old) and a growing Scots pine shoot. The emission rates of organic vapours (monoterpenes, methyl butenol (MBO), acetone and methanol) from vegetative buds of Scots pine during the dehardening and rapid shoot growth stages were one to two orders of magnitude higher than those from mature foliage. The normally assumed temperature dependency was not sufficient to explain the variations in emission rates during spring. The diurnal emission pattern of growing shoots differed from the diurnal cycle in temperature as well as from the diurnal emission pattern of mature shoots, which may be related to processes involved in shoot or needle elongation. Our findings imply that global estimations of monoterpene emission rates from forests are in need of revision, and that the physiological state of the plants should be taken into account when emissions of the reactive gases such as monoterpenes are estimated. The significant interannual variation in emission rates, related to changes in plant metabolic activity, has important implications to the aerosol precursor concentrations and chemical reactions in atmosphere, and potentially offers an explanation for the frequent aerosol formation events in spring.
3
Aalto, J., P. Kolari, P. Hari, V. M. Kerminen, P. Schiestl-Aalto, H. Aaltonen, J. Levula, E. Siivola, M. Kulmala e J. Bäck. "New foliage growth is a significant, unaccounted source for volatiles in boreal evergreen forests". Biogeosciences 11, n. 5 (6 marzo 2014): 1331–44. http://dx.doi.org/10.5194/bg-11-1331-2014.
Testo completoAbstract (sommario):
Abstract. Estimates of volatile organic compound (VOC) emissions from forests are based on the assumption that foliage has a steady emission potential over its lifetime, and that emissions are mainly modified by short-term variations in light and temperature. However, in many field studies this has been challenged, and high emissions and atmospheric concentrations have been measured during periods of low biological activity, such as in springtime. We conducted measurements during three years, using an online gas-exchange monitoring system to observe volatile organic emissions from a mature (1 year-old) and a growing Scots pine shoot. The emission rates of organic vapors from vegetative buds of Scots pine during the dehardening and rapid shoot growth stages were one to two orders of magnitude higher than those from mature foliage; this difference decreased and finally disappeared when the new shoot was maturing in late summer. On average, the springtime monoterpene emission rate of the bud was about 500 times higher than that of the mature needles; during the most intensive needle elongation period, the monoterpene emission rate of the growing needles was 3.5 higher than that of the mature needles, and in September the monoterpene emission rate of the same years' needles was even lower (50%) than that of the previous years' needles. For other measured compounds (methanol, acetone and methylbutenol) the values were of the same order of magnitude, except before bud break in spring, when the emission rates of buds for those compounds were on average about 20–30 times higher than that of mature needles. During spring and early summer the buds and growing shoots are a strong source of several VOCs, and if they are not accounted for in emission modeling a significant proportion of the emissions – from a few percent to even half of the annual cumulative emissions – will remain concealed. The diurnal emission pattern of growing shoots differed from the diurnal cycle in temperature as well as from the diurnal emission pattern of mature shoots, which may be related to processes involved in shoot or needle elongation. Our findings imply that global estimations of monoterpene emission rates from forests are in need of revision, and that the physiological state of the plants should be taken into account when emissions of the reactive gases such as monoterpenes are estimated.
4
Vanhatalo, A., T. Chan, J. Aalto, J. F. Korhonen, P. Kolari, T. Hölttä, E. Nikinmaa e J. Bäck. "Tree water relations trigger monoterpene emissions from Scots pine stem during spring recovery". Biogeosciences Discussions 12, n. 10 (22 maggio 2015): 7783–814. http://dx.doi.org/10.5194/bgd-12-7783-2015.
Testo completoAbstract (sommario):
Abstract. Tree canopies are known to emit large amounts of VOCs (volatile organic compounds) such as monoterpenes to the surrounding air. The main source for these is considered to be the green biomass, i.e. foliage, but emissions from the woody compartments have not been quantified. A VOC emission anomaly has been observed during transition from winter to summer activity. We analyzed if non-foliar components could partially explain the anomaly. We measured the VOC emissions from Scots pine (Pinus sylvestris L.) stems and shoots during the dehardening phase of trees in field conditions in two consecutive springs. We observed a large, transient monoterpene burst from stems, while the shoot monoterpene emissions and transpiration remained low. The burst lasted about 12 h. Simultaneously, an unusual night-time sap flow and an anomalous diurnal pattern of tree diameter were detected. Hence, we suggest that the monoterpene burst was a consequence of the recovery of the stem from winter-time. This indicates that the dominant processes and environmental drivers triggering the monoterpene emissions are different between stems and foliage.
5
Dehimeche, Nafissa, Bruno Buatois, Nadia Bertin e Michael Staudt. "Insights into the Intraspecific Variability of the above and Belowground Emissions of Volatile Organic Compounds in Tomato". Molecules 26, n. 1 (5 gennaio 2021): 237. http://dx.doi.org/10.3390/molecules26010237.
Testo completoAbstract (sommario):
The in-vivo monitoring of volatile organic compound (VOC) emissions is a potential non-invasive tool in plant protection, especially in greenhouse cultivation. We studied VOC production from above and belowground organs of the eight parents of the Multi-Parent Advanced Generation Intercross population (MAGIC) tomato population, which exhibits a high genetic variability, in order to obtain more insight into the variability of constitutive VOC emissions from tomato plants under stress-free conditions. Foliage emissions were composed of terpenes, the majority of which were also stored in the leaves. Foliage emissions were very low, partly light-dependent, and differed significantly among genotypes, both in quantity and quality. Soil with roots emitted VOCs at similar, though more variable, rates than foliage. Soil emissions were characterized by terpenes, oxygenated alkanes, and alkenes and phenolic compounds, only a few of which were found in root extracts at low concentrations. Correlation analyses revealed that several VOCs emitted from foliage or soil are jointly regulated and that above and belowground sources are partially interconnected. With respect to VOC monitoring in tomato crops, our results underline that genetic variability, light-dependent de-novo synthesis, and belowground sources are factors to be considered for successful use in crop monitoring.
6
Vanhatalo, A., T. Chan, J. Aalto, J. F. Korhonen, P. Kolari, T. Hölttä, E. Nikinmaa e J. Bäck. "Tree water relations can trigger monoterpene emissions from Scots pine stems during spring recovery". Biogeosciences 12, n. 18 (17 settembre 2015): 5353–63. http://dx.doi.org/10.5194/bg-12-5353-2015.
Testo completoAbstract (sommario):
Abstract. Tree canopies are known to emit large amounts of VOCs (volatile organic compounds) such as monoterpenes into the surrounding air. High VOC emission rates from boreal forests have been observed during the transition from winter to summer activity. The most important sources of these are considered to be the green foliage, understory vegetation and soil organisms, but emissions from the living stand woody compartments have so far not been quantified. We analyzed whether the non-foliar components could partially explain the springtime high emission rates. We measured the monoterpene emissions from Scots pine (Pinus sylvestris L.) stem and shoots during the dehardening phase of trees in field conditions in two consecutive springs. We observed a large, transient monoterpene burst from the stem, while the shoot monoterpene emissions remained low. The burst lasted about 12 h. Simultaneously, an unusual nighttime sap flow and a non-systematic diurnal pattern of tree diameter were detected. Hence, we suggest that the monoterpene burst was a consequence of the recovery of the stem from wintertime, and likely related to the refilling of embolized tracheids and/or phenological changes in the living cells of the stem. This indicates that the dominant processes and environmental drivers triggering the monoterpene emissions are different between the stem and the foliage.
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Rochester, I., C. Wood e B. Macdonald. "Quantifying nitrous oxide emissions from the foliage of cotton, maize and soybean crops". Crop and Pasture Science 66, n. 7 (2015): 689. http://dx.doi.org/10.1071/cp14301.
Testo completoAbstract (sommario):
Nitrous oxide (N2O) is a potent greenhouse gas, contributing to global warming. Most of the N2O emitted from cropping systems is derived from the soil and is closely related to the use of nitrogen (N) fertiliser. However, several reports have shown that small, yet significant, portions of the N2O flux from cropping systems are emitted from the crop foliage. This research aimed to quantify N2O emissions from the foliage of field-grown cotton (Gossypium hirsutum L.), and included maize (Zea mays L.) and soybean (Glycine max L.) for comparison. We also aimed to identify differences in the timing of N2O emissions from foliage during the day and over an irrigation cycle. Individual plants were isolated from the soil, and the atmosphere surrounding the encapsulated plants was sampled over a 30-min period. Subplots that were previously fertilised with urea at 0, 80, 160, 240 and 320 kg N ha–1 and then sown to cotton were used to measure N2O flux from plants on three occasions. N2O flux from cotton foliage was also measured on five occasions during an 11-day irrigation cycle and at five times throughout one day. N2O flux from foliage accounted for a small but significant portion (13–17%) of the soil–crop N2O flux. N2O flux from foliage varied with plant species, and the time of day the flux was measured. N2O flux from cotton plants was closely related to soil water content. Importantly, the application of N fertiliser was not related to the N2O flux from cotton plants. The most plausible explanation of our results is that a proportion of the N2O that was evolved in the soil was transported through the plant via evapotranspiration, rather than being evolved within the plant. Studies that exclude N2O emissions from crop foliage will significantly underestimate the N2O flux from the system.
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Canul-Solis, Jorge, María Campos-Navarrete, Angel Piñeiro-Vázquez, Fernando Casanova-Lugo, Marcos Barros-Rodríguez, Alfonso Chay-Canul, José Cárdenas-Medina e Luis Castillo-Sánchez. "Mitigation of Rumen Methane Emissions with Foliage and Pods of Tropical Trees". Animals 10, n. 5 (13 maggio 2020): 843. http://dx.doi.org/10.3390/ani10050843.
Testo completoAbstract (sommario):
Methane produced by enteric fermentation contributes to the emission of greenhouse gases (GHG) into the atmosphere. Methane is one of the GHG resulting from anthropogenic activities with the greater global warming contribution. Ruminant production systems contribute between 18% and 33% of methane emissions. Due to this, there has been growing interest in finding feed alternatives which may help to mitigate methane production in the rumen. The presence of a vast range of secondary metabolites in tropical trees (coumarins, phenols, tannins, and saponins, among others) may be a valuable alternative to manipulate rumen fermentation and partially defaunate the rumen, and thus reduce enteric methane production. Recent reports suggest that it is possible to decrease methane emissions in sheep by up to 27% by feeding them saponins from the tea leaves of Camellia sinensis; partial defaunation (54%) of the rumen has been achieved using saponins from Sapindus saponaria. The aim of this review was to collect, analyze, and interpret scientific information on the potential of tropical trees and their secondary metabolites to mitigate methane emissions from ruminants.
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Purser, Gemma, Julia Drewer, Mathew R. Heal, Robert A. S. Sircus, Lara K. Dunn e James I. L. Morison. "Isoprene and monoterpene emissions from alder, aspen and spruce short-rotation forest plantations in the United Kingdom". Biogeosciences 18, n. 8 (20 aprile 2021): 2487–510. http://dx.doi.org/10.5194/bg-18-2487-2021.
Testo completoAbstract (sommario):
Abstract. An expansion of bioenergy has been proposed to help reduce fossil-fuel greenhouse gas emissions, and short-rotation forestry (SRF) can contribute to this expansion. However, SRF plantations could also be sources of biogenic volatile organic compound (BVOC) emissions, which can impact atmospheric air quality. In this study, emissions of isoprene and 11 monoterpenes from the branches and forest floor of hybrid aspen, Italian alder and Sitka spruce stands in an SRF field trial in central Scotland were measured during two years (2018–2019) and used to derive emission potentials for different seasons. Sitka spruce was included as a comparison as it is the most extensive plantation species in the UK. Winter and spring emissions of isoprene and monoterpenes were small compared to those in summer. Sitka spruce had a standardised mean emission rate of 15 µgCg-1h-1 for isoprene in the dry and warm summer of 2018 – more than double the emissions in 2019. However, standardised mean isoprene emissions from hybrid aspen were similar across both years, approximately 23 µgCg-1h-1, and standardised mean isoprene emissions from Italian alder were very low. Mean standardised total monoterpene emissions for these species followed a similar pattern of higher standardised emissions in the warmer year: Sitka spruce emitting 4.5 and 2.3 µgCg-1h-1 for 2018 and 2019, aspen emitting 0.3 and 0.09 µgCg-1h-1, and Italian alder emitting 1.5 and 0.2 µgCg-1h-1, respectively. In contrast to these foliage emissions, the forest floor was only a small source of monoterpenes, typically 1 or 2 orders of magnitude lower than foliage emissions on a unit of ground area basis. Estimates of total annual emissions from each plantation type per hectare were derived using the MEGAN 2.1 model. The modelled total BVOC (isoprene and monoterpenes) emissions of SRF hybrid aspen plantations were approximately half those of Sitka spruce for plantations of the same age. Italian alder SRF emissions were 20 times smaller than from Sitka spruce. The expansion of bioenergy plantations to 0.7 Mha has been suggested for the UK to help achieve net-zero greenhouse gas emissions by 2050. The model estimates show that, with such an expansion, total UK BVOC emissions would increase between <1 % and 35 %, depending on the tree species planted. Whereas increases might be small on a national scale, regional increases might have a larger impact on local air quality.
10
Ashworth, Kirsti, Serena H. Chung, Karena A. McKinney, Ying Liu, J. William Munger, Scot T. Martin e Allison L. Steiner. "Modelling bidirectional fluxes of methanol and acetaldehyde with the FORCAsT canopy exchange model". Atmospheric Chemistry and Physics 16, n. 24 (15 dicembre 2016): 15461–84. http://dx.doi.org/10.5194/acp-16-15461-2016.
Testo completoAbstract (sommario):
Abstract. The FORCAsT canopy exchange model was used to investigate the underlying mechanisms governing foliage emissions of methanol and acetaldehyde, two short chain oxygenated volatile organic compounds ubiquitous in the troposphere and known to have strong biogenic sources, at a northern mid-latitude forest site. The explicit representation of the vegetation canopy within the model allowed us to test the hypothesis that stomatal conductance regulates emissions of these compounds to an extent that its influence is observable at the ecosystem scale, a process not currently considered in regional- or global-scale atmospheric chemistry models.We found that FORCAsT could only reproduce the magnitude and diurnal profiles of methanol and acetaldehyde fluxes measured at the top of the forest canopy at Harvard Forest if light-dependent emissions were introduced to the model. With the inclusion of such emissions, FORCAsT was able to successfully simulate the observed bidirectional exchange of methanol and acetaldehyde. Although we found evidence that stomatal conductance influences methanol fluxes and concentrations at scales beyond the leaf level, particularly at dawn and dusk, we were able to adequately capture ecosystem exchange without the addition of stomatal control to the standard parameterisations of foliage emissions, suggesting that ecosystem fluxes can be well enough represented by the emissions models currently used.
Tesi sul tema "Foliage emissions"
1
Zabaras, Dimitrios, University of Western Sydney, of Science Technology and Environment College e of Science Food and Horticulture School. "Determination of induced changes in foliar emissions of terpene-accumulating plants". THESIS_CSTE_SFH_Zabaras_D.xml, 2003. http://handle.uws.edu.au:8081/1959.7/809.
Testo completoAbstract (sommario):
Stress-induced changes in the emissions of volatiles from many economically-important plants have been demonstrated in studies over the past decade. Plants such as cotton and corn change both the composition and concentration of their emissions when subjected to wounding, herbivory and pathogen attack. Terpene-accumulating plants have been overlooked as potential objects of such studies although work on conifers has shown that species rich in constitutive defences can also exhibit induced responses. The aim of this study was to investigate whether terpene-accumulating plants respond to stress by altering their foliar emissions qualitatively and/or quantitatively. Species examined included Salvia officinalis (common sage), Melaleuca alternifolia (Australian tea tree) and Ocimum minimum (Bush basil). An experimental design was developed to eliminate factors such as leaf ontogeny that can affect the obtained results and complicate their interpretation. Small-scale solvent extraction and HS-SPME-based techniques were also developed; they enabled the quantitative determination of treatment-induced changes over periods ranging from 10 minutes to 6 months. Treatment of plants included mechanical wounding, herbivory, pathogen attack and chemical elicitation. Overall, statistically significant induced-changes were observed for both leaf-oil composition and concentration. The response of the different species used varied. O. minimum exhibited the greatest compositional changes whilst M. alternifolia was the only species for which oil-concentration changes were observed. The demonstrated changes were not as great as those reported in similar studies with non-terpene producing plants. The results indicate that the high metabolic costs associated with the production and storage of constitutive defences may be responsible for the limited induction of further defensive responsesDoctor of Philosophy (PhD)
2
Messenger, David James. "Impact of UV light on the plant cell wall, methane emissions and ROS production". Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4347.
Testo completoAbstract (sommario):
This study presents the first attempt to combine the fields of ultraviolet (UV) photobiology, plant cell wall biochemistry, aerobic methane production and reactive oxygen species (ROS) mechanisms to investigate the effect of UV radiation on vegetation foliage. Following reports of a 17% increase in decomposition rates in oak (Quercus robur) due to increased UV, which were later ascribed to changes in cell wall carbohydrate extractability, this study investigated the effects of decreased UV levels on ash (Fraxinus excelsior), a fast-growing deciduous tree species. A field experiment was set up in Surrey, UK, with ash seedlings growing under polytunnels made of plastics chosen for the selective transmission of either all UV wavelengths, UV-A only, or no UV. In a subsequent field decomposition experiment on end-of-season leaves, a significant increase of 10% in decomposition rate was found after one year due to removal of UV-B. However, no significant changes in cell wall composition were found, and a sequential extraction of carbohydrate with different extractants suggested no effects of the UV treatments on cell wall structure. Meanwhile, the first observations of aerobic production of methane from vegetation were reported. Pectin, a key cell wall polysaccharide, was identified as a putative source of methane, but no mechanism was suggested for this production. This study therefore tested the effect of UV irradiation on methane emissions from pectin. A linear response of methane emissions against UV irradiation was found. UV-irradiation of de-esterified pectin produced no methane, demonstrating esters (probably methyl esters) to be the source of the observed methane. Addition of ROS-scavengers significantly decreased emissions from pectin, while addition of ROS without UV produced large quantities of methane. Therefore, this study proposes that UV light is generating ROS which are then attacking methyl esters to create methane. The study also demonstrates that this mechanism has the potential to generate several types of methyl halides. These findings may have implications for the global methane budget. In an attempt to demonstrate ROS generation in vivo by UV irradiation, radio-labelling techniques were developed to detect the presence of oxo groups, a product of carbohydrate attack by ROS. Using NaB3H4, the polysaccharides of ash leaflets from the field experiment were radio-labelled, but did not show any significant decrease in oxo groups due to UV treatments. However, UV-irradiation of lettuce leaves showed a significant increase in radio-labelling, suggesting increased UV irradiation caused an increase in the production of ROS. The study shows that the use of this radio-labelling technique has the potential to detect changes in ROS production due to changes in UV levels and could be used to demonstrate a link between ROS levels and methane emissions.
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Zabaras, Dimitrios. "Determination of induced changes in foliar emissions of terpene-inducing plants /". View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030923.145135/index.html.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Western Sydney, 2003.A thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy, College of Science, Technology and Environment, University of Western Sydney, May, 2003. Includes bibliographical references.
4
Uzu, Gaëlle. "Spéciation, transfert vers les végétaux et approche toxicologique des émissions atmosphériques d'une usine de recyclage de plomb". Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT008A/document.
Testo completoAbstract (sommario):
Depuis la révolution industrielle en Europe (XIXe siècle), les nombreuses activités anthropiques ont provoqué des changements environnementaux globaux considérables. La composition de l'atmosphère terrestre en particulier, a été fortement modifiée par l'émission de polluants gazeux et particulaires. Actuellement, l'industrie métallurgique de seconde fusion contribue de façon significative aux émissions atmosphériques de métaux. C'est pourquoi ce travail de thèse s'est focalisé sur l'étude des transferts et impacts sur les sols, les végétaux et l'homme, des particules émises par le procédé de recyclage du plomb en relation avec leurs propriétés physico-chimiques. Trois sources principales d'émissions de particules ont été identifiées dans le procédé du recyclage du plomb et caractérisées en vue d'étudier les impacts potentiels sur les cibles végétales et humaines. Les particules échantillonnées (postes de travail et émissions canalisées) et ségréguées en fonction de leur taille (PMtot, PM10 et PM2,5) sont principalement composées de métaux (jusqu'à 50% en masse de la composition totale en métaux de transition, alcalins et alcalino-terreux), avec une majeur partie de plomb (25-45 %). Les spéciations majoritaires du plomb sont la galène (PbS), le sulfate du plomb (PbSO4) ou dérivés (xPbO.PbSO4 x=1,2 ou 3). L'étude du transfert des particules dans le sytème sol-plante a montré que, lorsque la taille des particules de process présentes dans le sol diminue (de 10µm à 2.5µm), le tranfert du plomb vers les parties aériennes des salades augmente de 20%. Le transfert foliaire de plomb issu des particules de process a été mis en évidence et des mécanismes d'absorption.ont été proposés. Enfin, l'étude exploratoire des particules riches en plomb sur la santé humaine a permis de montrer que la diminition de la taille des particules ingérées augmentait la bioaccessibilité gastrique du plomb. Dans le cas de l'inhalation, il a été démontré que les particules n'induisaient pas de cytotoxicité jusqu'à 50µg/cm2, mais provoquaient une réponse inflammatoire dose-dépendante des cellules épithéliales pulmonairesSince the Industrial Revolution in Europe (XIXe century), human activities have caused significant global environmental changes. The composition of the atmosphere in particular, has been extensively modified by the emission of gaseous and particulate pollutants. Currently, the secondary (or recycling) metallurgical industry contributes significantly to air emissions of metals. Therefore, this thesis focused on the study of transfers and impacts on soils, plants and humans, of particles from the recycling process of lead in relation to their physicochemical properties. Three main sources of particulate emissions have been identified in the process of recycling lead and characterized, to study the potential impacts on plant and human targets. The particles sampled (workstations and channelled emissions), and segregated according to their size (PMtot, PM10 and PM2, 5), are mainly composed of metals (up to 50% by weight of the total composition in transition metals alkaline and alkaline), with a major part of lead (25-45%). The major speciations of lead are galena (PbS), lead sulfate (PbSO4) or derivatives (xPbO.PbSO4 x = 1,2 or 3). The study of transfer of particles in the soil-plant system has shown that when the particle size of processes in the soil decreases (from 2.5µm to 10µm), the transfer of lead into the aerial parts of lettuce growing at 20 %. The uptake of lead from particles process by leaves has been demonstrated and mechanisms of absorption have been proposed. Finally, exploratory study of lead-rich particles on human health has shown that diminution of the size of particles ingested increased gastric bioaccessibility of lead. In the case of inhalation, it was shown that the particles did not induce cytotoxicity up 50µg/cm2, but caused a dose-dependent inflammatory response of lung epithelial cells
5
Zabaras, Dimitrios. "Determination of induced changes in foliar emissions of terpene-accumulating plants". Thesis, 2003. http://handle.uws.edu.au:8081/1959.7/809.
Testo completoAbstract (sommario):
Stress-induced changes in the emissions of volatiles from many economically-important plants have been demonstrated in studies over the past decade. Plants such as cotton and corn change both the composition and concentration of their emissions when subjected to wounding, herbivory and pathogen attack. Terpene-accumulating plants have been overlooked as potential objects of such studies although work on conifers has shown that species rich in constitutive defences can also exhibit induced responses. The aim of this study was to investigate whether terpene-accumulating plants respond to stress by altering their foliar emissions qualitatively and/or quantitatively. Species examined included Salvia officinalis (common sage), Melaleuca alternifolia (Australian tea tree) and Ocimum minimum (Bush basil). An experimental design was developed to eliminate factors such as leaf ontogeny that can affect the obtained results and complicate their interpretation. Small-scale solvent extraction and HS-SPME-based techniques were also developed; they enabled the quantitative determination of treatment-induced changes over periods ranging from 10 minutes to 6 months. Treatment of plants included mechanical wounding, herbivory, pathogen attack and chemical elicitation. Overall, statistically significant induced-changes were observed for both leaf-oil composition and concentration. The response of the different species used varied. O. minimum exhibited the greatest compositional changes whilst M. alternifolia was the only species for which oil-concentration changes were observed. The demonstrated changes were not as great as those reported in similar studies with non-terpene producing plants. The results indicate that the high metabolic costs associated with the production and storage of constitutive defences may be responsible for the limited induction of further defensive responses
6
Scarr, Mark J. "The use of stomatal frequency from three Australian evergreen tree species as a proxy indicator of atmospheric carbon dioxide concentration". Thesis, 2011. https://vuir.vu.edu.au/16044/.
Testo completoAbstract (sommario):
Increasing atmospheric carbon dioxide concentration ([CO2]) is the main contributing factor to anthropogenically derived global climate change. The impact of climate change upon terrestrial ecosystems is still uncertain. If information can be obtained on how past fluctuations in [CO2] and temperature has affected terrestrial communities this knowledge can increase our understanding as to how future climate change may impact upon modern-day ecosystems.
Foliar stomatal frequency analysis is a proxy-CO2 measure that may provide estimates of atmospheric [CO2] from subfossil or fossil leaf material. Currently, the majority of the research in this field has been conducted on deciduous Northern Hemisphere species including extant and fossil material. Southern Hemisphere fossil species are
currently under-represented in the fossil proxy-CO2 database. The rate of climate change in the Southern Hemisphere is less than that experienced in the Northern
Hemisphere, so using Northern Hemisphere derived training sets to provide Southern Hemisphere CO2 estimates may introduce confounding errors. Therefore, the use of
Southern Hemisphere training sets on Southern Hemisphere fossil material will provide more accurate atmospheric CO2 estimations. This thesis will contribute to the field of knowledge by determining the applicability of three Southern Hemisphere evergreen tree species to be used as potential proxy-CO2 indicator species.
Capitoli di libri sul tema "Foliage emissions"
1
Schjøerring, Jan K. "Ammonia Emission from the Foliage of Growing Plants". In Trace Gas Emissions by Plants, 267–92. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-12-639010-0.50017-0.
Testo completo
2
Jamaladdeen, Rawaa, Bruno Coudour, Fabienne Dédaldéchamp, Laurent Lemée, Jean-Pierre Garo e Hui-Ying Wang. "Influence of combined hydric and thermal stresses on Rosmarinus officinalis and Cistus albidus". In Advances in Forest Fire Research 2022, 1665–70. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_255.
Testo completoAbstract (sommario):
Wildfires are a growing threat, especially in Mediterranean climate areas during periods of drought. Wildfire research community continues to investigate propagation mechanisms on a large scale considering the thermal and fluid mechanics effects, or the main fire emissions (CO, CO2, H2O, H2, CH4). However, research on the effect of abiotic stresses on the plant emission during wildfires remains lacking, despite the fact that Mediterranean are considered important BVOC emitting and storing species. This article addresses the effect of combined hydric and thermal stresses on the volatile’s emission behaviours of two important Mediterranean shrub species; Rosmarinus officinalis and Cistus albidus that are largely consumed in wildfires. Different levels of hydric stress were applied on plants of the two species in a greenhouse of the EBI laboratories of the University of Poitiers. Thermal stress was executed by placing the water stressed plants inside a hermetic enclosure equipped with a radiant panel of maximal radiant heat flux of 84kW.m-2 and a fire-resistant glazed window for visualisation. The gaseous emissions of the plants under thermal stresses were collected and analysed by two complementary devices: an instantaneous gas analyser for CO, CO2, H2 and CH4, and adsorbent tubes by using the techniques of adsorption and desorption (by pyrolysis) for emission collection and analyses, respectively. Simultaneous Py/GC-MS experiments were realised at IC2MP on a foliar scale of the water stressed plants in order to gain more control and precision in emission analyses. The heating tests showed a good reproducibility for pyrolyses of leaf samples and interesting variations between the monoterpene emissions of stressed and unstressed plants. At plant scale, number of tests for each plant species at a given hydric stress level were insufficient to give trends and strong results because of some imposed technical problems and the constraints of public health crisis. However, these tests allowed us to adapt experimental protocols and devices for further testing such as: plant location and fixation, heat flux ramp, sampling location, use of adsorbent tubes, hydric stress duration and normalisation of measured concentrations according to the plant size.
Atti di convegni sul tema "Foliage emissions"
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Patt, Joseph. "Effects of exogenous application of methyl jasmonate on foliar volatile emission in sweet orange (Citrussinensis) and aggregation behavior of Asian citrus psyllid (Diaphorina citri)". In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.109161.
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