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The foliar penetration of polar compoundsHill, E. M. H. January 1986 (has links)
No description available.
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Interaction between salinity and nutrients in cottonMemon, Jawed Akhtar January 1999 (has links)
No description available.
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Nutrient alterations in Scots pines (<em>Pinus sylvestris</em> L.) under sulphur and heavy metal pollutionRautio, P. (Pasi) 27 September 2000 (has links)
Abstract
In this study, mineral nutrition and its relation to the vigour of Scots pines growing under the influence of sulphur, copper and nickel stress were investigated. This was done by analysing the nutrient status and needle damage of pines along a pollution transect extending from the proximity of a large S, Cu and Ni emitters on the Kola Peninsula to a background area in Finnish Lapland. Additionally, pine seedlings were exposed to Cu and Ni stress in order to gain more detailed information about the mechanisms behind metal stress.
The total sulphur concentrations of the youngest needles in the vicinity of the largest point source were about double compared to those in the reference area (< 800 mg in kg of dry needles vs. > 1900 mg kg-1). In the case of Cu and Ni, this difference was close to 100-fold (from 2-3 mg kg-1 to over 250 mg kg-1). While the elevated sulphur concentrations were not attributable to particle deposition, the particles on needle surfaces raised the total concentrations of Cu and Ni occasionally over 1.5-fold compared to the inside concentrations. The Mn and Zn concentrations showed a decreasing trend, whereas K and P slightly increased towards the Monchegorsk smelters. Enhanced needle senescence and tip necrosis were related to high total foliar levels of Cu, Ni and S and low levels of Zn and Mn. Stomatal chlorosis and other discolourations showed a distinct relation to high SO2 levels in the air and also to high foliar concentrations of Ca, Fe, Si and Cl. Particles deposited on needle surfaces did not cause directly visible injuries in pines.
In seedlings, Cu and Ni were enriched in roots: the Ni concentration was up to 16-fold and the Cu concentration 6-fold compared to that added into the soil. While Cu was mostly retained in roots, Ni had much easier access to foliage. The effect of metal stress on other nutrients varied between nutrients, plant parts and metals added. Soil analyses from both the field study and the seedling experiment gave mostly a weak estimation about the plant availability of nutrients. Foliar nutrients remained above the deficiency limits in all studies and were hence not the primary cause for the decrease of pine vigour and the consequent growth retardation and forest decline.
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Spéciation, transfert vers les végétaux et approche toxicologique des émissions atmosphériques d'une usine de recyclage de plomb / Speciation, plant transfer and toxicological approach for atmospheric fallout from a lead-recyvling plantUzu, Gaëlle 30 October 2009 (has links)
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 pulmonaires. / Since 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
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