Conserved histidine of metal transporter AtNRAMP1 is crucial for optimal plant growth under manganese deficiency at chilling temperatures

Manganese (Mn) is an essential nutrient required for plant growth, in particular in the process of photosynthesis. Plant performance is influenced by various environmental stresses including contrasting temperatures, light or nutrient deficiencies. The molecular responses of plants exposed to such stress factors in combination are largely unknown. 

Screening of 108 Arabidopsis thaliana (Arabidopsis) accessions for reduced photosynthetic performance at chilling temperatures was performed and one accession (Hog) was isolated. Using genetic and molecular approaches, the molecular basis of this particular response to temperature (GxE interaction) was identified. 

Hog showed an induction of a severe leaf chlorosis and impaired growth after transfer to lower temperatures. We demonstrated that this response was dependent on the nutrient content of the soil. Genetic mapping and complementation identified NRAMP1 as the causal gene. Chlorotic phenotype was associated with a histidine to tyrosine (H239Y) substitution in the allele of Hog NRAMP1. This led to lethality when Hog seedlings were directly grown at 4 degrees C. 

Chemical complementation and hydroponic culture experiments showed that Mn deficiency was the major cause of this GxE interaction. For the first time, the NRAMP-specific highly conserved histidine was shown to be crucial for plant performance.

The extended phenotype of Scots pine Pinus sylvestris structures the understorey assemblage

Heritable variation in plant secondary compounds in dominant species has been hypothesised to effect ecosystem function and the structure of associated assemblages of plants, microbes and animals. The functioning of this extended phenotype in relation to the understorey vegetation composition was tested within a boreal forest system dominated by Pinus sylvestris which contains a range of monoterpenes, the composition of which is largely under genetic control. A variance partitioning approach was adopted to identify the relative importance of tree chemistry, environment, spatial location and tree architecture in controlling the distribution of species in the ground flora under individual trees. The monoterpene composition of the pine needles appeared to contribute significantly to controlling understorey vegetation composition, but was less important than environmental factors, though similar to spatial factors. Thus there appears to be a link between variation in the chemical composition of the single, dominant tree species within this system and the pattern of occurrence and abundance in other species at the same trophic level.

A techno-economic feasibility study of high altitude wind power in Northern Ireland

Globally the amount of installed terrestrial wind power both onshore and offshore has grown rapidly over the last twenty years. Most large onshore and offshore wind turbines are designed to harvest winds within the atmospheric boundary layer, which can be vary variable due to terrain and weather effects. The height of the neutral atmospheric boundary layer is estimated at above 1300m. A relatively new concept is to harvest more consistent wind conditions above the atmospheric boundary layer using high altitude wind harvesting devices such as tethered kites, air foils and dirigible rotors. This paper presents a techno-economic feasibility study of high altitude wind power in Northern Ireland. First this research involved a state of the art review of the resource and the technologies proposed for high altitude wind power. Next the techno-economic analysis involving four steps is presented. In step one, the potential of high altitude wind power in Northern Ireland using online datasets (e.g. Earth System Research Laboratory) is estimated. In step two a map for easier visualisation of geographical limitations (e.g. airports, areas of scenic beauty, flight paths, military training areas, settlements etc.) that could impact on high altitude wind power is developed. In step three the actual feasible resource available is recalculated using the visualisation map to determine the ‘optimal’ high altitude wind power locations in Northern Ireland. In the last step four the list of equipment, resources and budget needed to build a demonstrator is provided in the form of a concise techno-economic appraisal using the findings of the previous three steps.

The health profile of football/soccer players in Northern Ireland - a review of the uefa pre-participation medical screening procedure.

BACKGROUND:
It is compulsory that domestic football/soccer teams in UEFA competitions organise players' pre-participation medicals. Although screening guidelines have been established, these remain controversial. The findings of medical examinations can have lasting consequences for athletes and doctors. No previous studies have reported UEFA pre-participation screening results in semi-professional footballers. This study aims to further knowledge regarding 'normal' data in this population.

METHOD:
Retrospective audit and analysis of records of pre-season medicals for all male first-team players at one semi-professional Northern Ireland Premiership team between 2009-2012. Medicals were conducted by the club doctor following the UEFA proforma. Height, weight, blood pressure (BP), full blood count (FBC), dipstick urinalysis and resting electrocardiogram (ECG) were conducted by an independent nurse. Only one ECG must be documented during a player's career; other tests are repeated yearly.

RESULTS:
89 medicals from 47 players (6 goalkeepers, 11 defenders, 22 midfielders and 8 attackers; mean age 25.0 years (SD 4.86)) were reviewed. Mean height of the players was 179.3 cm (SD 5.90) with a mean weight of 77.6 kg (SD 10.5). Of 89 urine dipsticks, 7 were positive for protein; all 7 were normal on repeat testing following 48 hours of rest. Of 40 ECGs (mean ventricular rate 61.2 bpm (SD 11.6)), one was referred to cardiology (right bundle branch block; prolonged Q-T interval). No players were excluded from participation.

CONCLUSIONS:
This study provides important information about 'normal' values in a population of semi-professional footballers. Urinalysis showing protein is not uncommon but is likely to be normal on repeat testing.

Influence of rheology on the quality of surface finish of cement-based mortars

Aesthetics of concrete structures is directly related to the quality of their surface finish. The objective of this investigation was to examine the effect of rheological properties of cement-based mortars on the quality of their surface finish. The study was divided into two phases. Firstly, the influence of the mix composition of mortars, viz. the water to cement (w/c) ratio, the sand content and the superplasticiser (SP) dosage on their rheology was evaluated. Secondly, the surface finish quality was characterised and related to the rheology of the studied systems. Rheology of these materials, i.e. the yield value, was measured using a vane viscometer. The quality of the surface finish was assessed by quantification of the surface air voids by analysing digital photographs of the mould finished sample surfaces. It was found that an increase in the w/c ratio and the SP content decreased the yield value, whilst the increase in the sand content had an opposite effect. When the surface quality is concerned, an increase in the yield value was found to increase the total content of the surface air voids and especially those with size smaller than 1 mm in diameter. Moreover, the analysis of the location of the surface air voids along the height of the sample revealed that with the increase in the yield value their concentration was higher in the bottom section of the analysed samples.

Genetically Determined Height and Coronary Artery Disease

Background: The nature and underlying mechanisms of an inverse association between adult height and the risk of coronary artery disease (CAD) are unclear. 
Methods: We used a genetic approach to investigate the association between height and CAD, using 180 height-associated genetic variants. We tested the association between a change in genetically determined height of 1 SD (6.5 cm) with the risk of CAD in 65,066 cases and 128,383 controls. Using individual-level genotype data from 18,249 persons, we also examined the risk of CAD associated with the presence of various numbers of height-associated alleles. To identify putative mechanisms, we analyzed whether genetically determined height was associated with known cardiovascular risk factors and performed a pathway analysis of the height-associated genes. 
Results: We observed a relative increase of 13.5% (95% confidence interval [CI], 5.4 to 22.1; P<0.001) in the risk of CAD per 1-SD decrease in genetically determined height. There was a graded relationship between the presence of an increased number of height-raising variants and a reduced risk of CAD (odds ratio for height quartile 4 versus quartile 1, 0.74; 95% CI, 0.68 to 0.84; P<0.001). Of the 12 risk factors that we studied, we observed significant associations only with levels of low-density lipoprotein cholesterol and triglycerides (accounting for approximately 30% of the association). We identified several overlapping pathways involving genes associated with both development and atherosclerosis. 
Conclusions: There is a primary association between a genetically determined shorter height and an increased risk of CAD, a link that is partly explained by the association between shorter height and an adverse lipid profile. Shared biologic processes that determine achieved height and the development of atherosclerosis may explain some of the association. (Funded by the British Heart Foundation and others.)

Identification of Road Irregularities via Vehicle Accelerations

A periodic monitoring of the pavement condition facilitates a cost-effective distribution of the resources available for maintenance of the road infrastructure network. The task can be accurately carried out using profilometers, but such an approach is generally expensive. This paper presents a method to collect information on the road profile via accelerometers mounted in a fleet of non-specialist vehicles, such as police cars, that are in use for other purposes. It proposes an optimisation algorithm, based on Cross Entropy theory, to predict road irregularities. The Cross Entropy algorithm estimates the height of the road irregularities from vehicle accelerations at each point in time. To test the algorithm, the crossing of a half-car roll model is simulated over a range of road profiles to obtain accelerations of the vehicle sprung and unsprung masses. Then, the simulated vehicle accelerations are used as input in an iterative procedure that searches for the best solution to the inverse problem of finding road irregularities. In each iteration, a sample of road profiles is generated and an objective function defined as the sum of squares of differences between the ‘measured’ and predicted accelerations is minimized until convergence is reached. The reconstructed profile is classified according to ISO and IRI recommendations and compared to its original class. Results demonstrate that the approach is feasible and that a good estimate of the short-wavelength features of the road profile can be detected, despite the variability between the vehicles used to collect the data.

Electron-impact ionization of Al2+

We report on a nonperturbative R-matrix with PseudoStates (RMPS) calculation for the electron-impact ionization cross section of the ground state of Al2+. We include both the direct ionization of the 3s and 2p subshells and the indirect ionization from the 2p subshell. This calculation, thus, includes extra decay channels for the indirect-ionization process not included in previous RMPS calculations. This lowers the total-ionization cross section, resulting in closer agreement with the most recent experimental measurements. This calculation also shows better agreement with the position and height of the resonant-excitation double autoionization features seen in the experiment.

Genotoxicity and cytotoxicity of Cr(VI) and Pb²+ in Pisum sativum

A toxicidade dos metais é uma problemática que envolve a saúde humana e o ambiente, sendo necessária uma vigilância constante e uma avaliação dos danos precisa e robusta. As plantas, como principal fonte alimentar e de produtos, são de vital importância à sociedade humana. Devido a serem seres sesseis, este grupo é um dos mais afectados por poluentes, tornandoos objectos de estudo extremamente interessantes. O objectivo desta tese foi avaliar os efeitos genotóxicos e citotóxicos do Cr(VI) e Pb2+ na espécie modelo Pisum sativum L. No capitulo I é introduzida a problemática da toxicidade de ambos os metais, com especial relevo nas plantas, bem como as abordagens mais actuais no estudo da geno e citotoxicidade. No capitulo II são apresentados os resultados dos estudos da genotoxicidade do Pb2+ (II-1) e Cr(VI) (II-2 e II-3), tendo sido realizados analises de dano ao DNA a vários níveis e alterações do ciclo celular (II-1 e II-2), bem como a detecção de instabilidade de microssatelites (II-1 e II-3), que é um indicador do estado funcional do mecanismo de reparação do DNA. O capítulo III aborda o efeito de stresses abióticos na capacidade fotossintética da espécie modelo. No capítulo III-1, realizou-se um estudo pioneiro de avaliação da aplicabilidade da citometria de fluxo no estudo da fotossíntese, mais concretamente no estado funcional e estrutural dos cloroplastos, quando expostos a um inibidor da fotossíntese (Paraquat). Os dados obtidos neste estudo encorajaram a aplicação da técnica nos capítulos III-2 e III-3, nos quais se analisaram os efeitos dos metais Pb2+ (III- 2) e Cr(VI) (III-3) na capacidade fotossintética de plantas expostas a este metal; em estudos que envolveram vários marcadores clássicos, para alem dos da citometria de fluxo. Finalmente, no capítulo IV são apresentadas as conclusões finais do trabalho, uma comparativa entre os efeitos e níveis de toxicidade dos dois metais em estudo e são apontadas algumas perspectivas para futuros estudos, levantadas pelos dados obtidos.

Indoor air quality in elementary schools of Lisbon and Aveiro

Tem havido uma preocupação crescente com a qualidade do ar interior (QAI) nas escolas em muitos países. Muitos estudos epidemiológicos têm encontrado diferenças regionais entre ambientes interiores. Apesar da elevada incidência de asma e rinite na população infantil, praticamente nada se sabia sobre a QAI em escolas portuguesas. A percepção dos problemas de QAI é crucial para avaliar os riscos para a saúde e rendimento dos estudantes, e para sugerir meios de reduzir a exposição a poluentes indesejáveis. Neste estudo procurou-se obter as concentrações de poluentes de interesse em estabelecimentos de ensino do 1º ciclo de Lisboa e Aveiro, estimar o estado atual de casos de asma e rinite em escolas primárias da capital, avaliar a influência de diferentes materiais das salas de aula/construção e hábitos escolares na QAI, identificar potenciais fontes de poluentes nos interiores e exteriores das salas de aula e propor medidas mitigadoras. Catorze escolas de Lisboa foram visitadas para obter a caracterização física das construções em termos de estrutura, ventilação, materiais de acabamento, produtos de limpeza, densidade de ocupação e potenciais fontes interiores de poluição. Os estudantes foram questionados sobre os seus hábitos e sintomas respiratórios através de inquéritos do modelo ISAAC (International Study of Asthma and Allergies in Childhood). Durante a primavera, outono e inverno (2008-2010), nas salas de aula e pátios, foram monitorizados, por amostragem passiva, compostos orgânicos voláteis (COVs), carbonilos e dióxido de azoto (NO2). Foram também medidos parâmetros de conforto e níveis de microrganismos. Duas escolas localizadas, uma no centro da cidade e outra na região suburbana, em Aveiro foram estudadas em 2010. Parâmetros de conforto, microrganismos, COVs, NO2, material particulado (PM10) foram medidos no interior e no exterior de ambas escolas. Os iões solúveis, carbono orgânico e elementar (OC e EC), e compostos orgânicos presentes no material particulado foram subsequentemente analisados em laboratório. Uma medida mitigadora - fitoremediação - foi avaliada na escola do centro da cidade de Aveiro em 2011. Os resultados do estudo mostraram que a QAI é pior do que a do ar exterior. Em geral, os níveis de CO2 e dos bioaerosóis excederam os níveis máximos aceitáveis para o conforto dos ocupantes estipulado pelas regulamentações portuguesas. Quase todos os COVs e carbonilos identificados mostraram razões interior/exterior (I/E) maiores que uma unidade, o que demonstra a importante contribuição de fontes interiores em todas as escolas. As razões I/E das concentrações de NO2 nunca excederam a unidade. Os níveis interiores diários de PM10 foram sempre maiores que os exteriores, exceto nos fins de semana. Após a colocação de plantas numa das salas de aula, observou-se uma redução estatisticamente significativa nos níveis de CO2, COVs, carbonilos, PM10, OC, e dos iões nitrato, sulfato, amónia, cálcio e carbonato. A possível redução dos níveis de poluentes no interior após a colocação de plantas pode representar uma solução de baixo custo para reduzir a exposição a muitos compostos, melhorar o rendimento e aumentar o bem estar dos alunos e professores em sala de aula.

Synthesis and biological activities of polyphenolic hybrids - evaluation of anti-cancer, anti-inflammatory and antioxidant activities

Os compostos polifenólicos constituem uma classe de metabolitos secundários de plantas, mas existe também uma enorme quantidade de derivados sintéticos ou semi-sintéticos contendo múltiplas unidades fenólicas. Estes compostos apresentam importantes características biológicas, que dependem das suas estruturas básicas. Certos derivados desta família de compostos, tais como flavonoides, cromonas e cumarinas contribuem para os benefícios da dieta humana, e partilham o núcleo de benzopiran-(2 e 4)-ona ou benzofuran-3-ona. A presente dissertação inclui uma introdução geral e três capítulos que descrevem as novas rotas sintéticas estabelecidas para a preparação de novos híbridos de diversos compostos polifenólicos, assim como a sua elucidação estrutural e termina com a presentação dos resultados da avaliação biológica desses mesmos compostos. No segundo capítulo discute-se a preparação de híbridos de pirimidina- e imidazolidina-polifenóis, especialmente a síntese diastereoseletiva de novos híbridos benzofuran-3-ona-hidantoína e derivados de uracilo. A rota sintética envolve a ação de carbodiimidas sobre os ácidos cromona-(2- e 3)-carboxílicos num só passo ou em dois passos sequenciais, catalisada por uma base orgânica ou inorgânica. O terceiro capítulo descreve reações do tipo adições conjugadas 1,4 - hetero-ciclisações em cascata de compostos 1,3-dicarbonílicos em ácido cromona-3-carboxílico catalisadas por uma base orgânica, que originaram novas cromonas, cromanonas e flavonas polissubstituídas. As bispiranonas [bispiran-2 e 4)-onas] foram elaboradas numa reacção de acoplamento da 4-hidroxicumarina ou da lactona do ácido triacético com o ácido cromona-3-carboxílico ou precursores formil-funcionalizados (ω-formil-2’-hydroxy acetofenonas e cromona-3-carbaldeídos) utilizando organocatálise básica. Finalmente, alargou-se o estudo das adições conjugadas 1,4 para uma variedade de 4-hidroxipiran-2-onas e cetonas α,β-insaturadas para originar novos análogos de warfarina. Obteve-se uma variedade de estruturas complexas por hibridação das unidades de 4-hidroxicumarina ou da lactona do ácido triacético com os novos derivados de cromonas polissubstituídas. Todos as reações foram executadas em condições suaves e ambientalmente favoráveis, utilizando a 4-pirrolidinopiridina como organocatalisador básico. As estruturas dos novos híbridos polifenólicos foram caracterizados por técnicas espectroscópicas de alta resolução, incluindo espectroscopia de ressonância magnética nuclear (1D e 2D) e por difractometria de raios-X, que nos permitiram resolver o complexidade estrutural dos compostos sintetizados. O quarto capítulo apresenta os resultados da avaliação biológica obtidos com os híbridos polifenólicos sintetizados neste trabalho, mostrando a possibilidade de seu envolvimento na terapia do cancro. A maioria dos compostos foram avaliados quanto ao seu efeito sobre a citotoxicidade e proliferação de células leucémicas e ao seu envolvimento na regulação de via pró-inflamatória NF-kB, na qual, os híbridos de biscumarinas exibiram actividades elevadas (IC50 = 6-19 μM para inibição de NF-kB depois de 8 horas de incubação e IC50 = 15-39 μM para efeitos citotóxicos em células cancerosas, após 24 horas de incubação). Uma inibição moderada das enzimas HDAC e Cdc25 foi induzida pelos derivados de benzofuran-3-ona-hidantoína. Catorze dos novos derivados polifenólicos polissubstituídos, tendo como estrutura básica a benzopiran-4-ona, foram avaliados pela sua actividade quimiopreventiva do cancro mediada pela indução de sinalização citoprotectora Nrf2 (fator 2 relacionado com o fator nuclear da proteína E2) e capacidade para inibir a proliferação das células de cancro da mama. Os derivados da classe das cromanonas foram identificados como os indutores mais potentes da actividade Nrf2. As concentrações necessárias para aumentar a actividade de luciferase em 10 vezes (C10) foram de 2,8-21,3 μM. Todos os novos híbridos polifenólicos que apresentam atividade citotóxica e anti-proliferativa não afectam o crescimento de células saudáveis periféricas do sangue (PBMC) (IC50 > 50 μM), indicando a sua seletividade para as células cancerosas e sugerindo que alguns deles são estruturalmente interessantes para posteriores análises. A avaliação da atividade antioxidante utilizando os testes do radical livre DPPH e o poder redutor do ião férrico FRAP foram realizados em algumas estruturas híbridas polifenólicas.

Structural characterization and biological activity of polysaccharides from infusions used in the popular tradition

The use of plants with medicinal purposes is an ancient practice still very common in developing regions, and is rapidly spreading in industrialized countries. This fact is evidenced by the large number of ethnobotanical studies found in the literature referring that these plants are often used as decoctions and infusions. In most studies the reported biological activities are attributed to the presence of phenolic compounds, due to their antioxidant properties, and to polysaccharides, with its anti-tumoral properties. In “Trás-os-Montes” region, some of the most popular infusions used by the popular medicine are prepared with the dried leaves of Fraxinus angustifolia, the dried shoots of Mentha suaveolens, and the dried inflorescences of Pterospartum tridentatum. However, there are no studies about the polysaccharides present in these infusions. Thus, through the structural characterization of the polysaccharides present in the infusions of F. angustifolia, M. suaveolens, and P. tridentatum, the present PhD thesis intends to evaluate the possible relation between polysaccharides and the immunostimulatory activity that these infusions might present. In a preliminary phase, infusions of F. angustifolia were prepared according to the popular tradition, and it was observed that the obtained water soluble material contained approximately 85% of material non-retained in C18 cartridges, with hydrophilic characteristics, with the remaining 15% comprising retained-material with hydrophobic characteristics. It was also shown that the infusions only contained between 2 and 4% of high molecular weight material (HMWM), which comprised approximately 30% of carbohydrate material. Sugar and methylation analysis of the HMWM suggested the presence of pectic polysaccharides, together with type II arabinogalactans, mannans, and xyloglucans. However, the amount of material obtained is to low for the fractionation, and structural analysis of the polysaccharides present. The 4 h decoction, divided in two periods of 2 h, with water renewal, allowed to increase the HMWM yield, relatively to the infusions traditional infusions. It was also observed that the decoction also allowed to increase the HMWM proportion of carbohydrate material, due to an increase in the proportion of uronic acid present, although the neutral sugar residues seemed to be detected in similar proportions. Therefore, in all the experiments subsequently performed, the HMWM used was obtained through the decoction of F. angustifolia dried leaves, M. suaveolens dried shoots, and P. tridentatum dried inflorescences. x After the fractionation, through ethanol precipitation, and anion exchange chromatography, of the polysaccharides from the HMWM obtained by the decoction of the vegetable material of the distinct studied plants, it was observed the presence of high proportions of pectic polysaccharides, containing type I arabinogalactans, together with minor proportions of type II arabinogalactans, mannans, and xyloglucans. The presence of pectic polysaccharides in the extracts from F. angustifolia was also evidenced through endo-polygalacturonase treatment, and ESI-MS and ESI-MS/MS experiments. The detection of linked pentose and uronic acid residues, also seemed to suggest the presence of xylogalacturonan domains in the pectic polysaccharides from F. angustifolia. The extracts from F. angustifolia dried leaves also contained type II arabinogalactans that exhibited a higher structural diversity than those detected in the M. suaveolens, and P. tridentatum extracts, particularly in the substitution degree of the galactan backbone, and in the extension of the (1→5)-Araf side chains. Moreover, for all the plants studied, it was also observed that the type II arabinogalactans, extracted during the 2nd 2h of the extraction process, exhibited a substitution degree of the galactan backbone higher than those extracted during the 1st 2h. The extracts from P. tridentatum dried inflorescences contained higher proportions of mannans, and also of xyloglucans, both presenting a substitution degree higher than those, which were detected in lower proportion in the extracts of F. angustifolia and M. suaveolens. Through ESI-MS and ESI-MS/MS it was possible to evidence that the mannans present in the extracts of P. tridentatum presented acetyl groups on the O-2 of the mannosyl residues. It was also evidenced that the P. tridentatum mannans were more extensively acetylated than the mannans detected in the coffee infusion, LBG, and other non-conventional mannan sources. Moreover, it was detected the presence of oligosaccharides comprising hexose residues linked to non acetylated pentose residues, suggesting the possible presence of arabinose residues in the mannans from P. tridentatum extracts. The immunostimulatory activity of three fractions isolated from the extracts of F. angustifolia, M. suaveolens, and P. tridentatum, was tested and an increase in the NO production by macrophages, without compromising their cellular viability, was observed. The type I, and type II arabinogalactans detected in the extracts from F. angustifolia, and M. suaveolens seem to have contributed for the observed immunostimulatory activity. For the fraction from P. tridentatum, the mannans acetylation, and the presence of type I, and type II arabinogalactans seemed to contribute for the macrophage immunostimulatory activity observed. The possible presence of storage xyloglucans from the inflorescences seeds, also seems to have contributed for the immunostimulatory activity registered when the macrophages were stimulated with higher extract concentrations. The results obtained allow to conclude that the extracts of F. angustifolia dried leaves, M. suaveolens dried shoots, and P. tridentatum dried inflorescences contained high proportions of pectic polysaccharides, exhibiting type I arabinogalactans, together with other polysaccharides, such as type II arabinogalactans, mannans, and xyloglucans. This polysaccharide mixture seems to have contributed to the immunostimulatory activity of fractions isolated from the extracts of the studied plants. Therefore, as the same type of polysaccharides seem to be present in the decoctions and in the infusions, it seems possible that the polysaccharides might contribute for the therapeutic properties frequently associated by the popular tradition to the infusions of these plants.

Tolerance of young (Ceratonia siliqua L.) carob rootstock to NaCl

One-year-old carob (Ceratonia siliqua L.) rootstock was grown in fertilised substrate to evaluate the effects of NaCl salinity stress. The experiment consisted of seven treatments with different concentrations of NaCl in the irrigation water: 0 (control), 15, 30, 40, 80, 120 and 240 (mmol L(-1)), equivalent to electrical conductivities of 0.0, 1.5, 2.9, 3.9, 7.5, 10.9 and 20.6 dS m(-1), respectively. Several growth parameters were measured throughout the experimental period. At the end of the experiment, pH, extractable P and K, and the electrical conductivity of the substrate were assessed in each salinity level. On the same date, the mineral composition of the leaves was compared. The carob rootstock tolerated 13.4 dS m(-1) for a period of 30 days but after 60 days the limit of tolerance was only 6.8 dS m(-1). Salt tolerance indexes were 12.8 and 4.5 for 30 and 60 days, respectively. This tolerance to salinity resulted from the ability to function with concentrations of Cl(-) and Na(+) in leaves up to 24.0 and 8.5 g kg(-1), respectively. Biomass allocation to shoots and roots was similar in all treatments, but after 40 days the number of leaves was reduced, particularly at the larger concentrations (120 and 240 mmol NaCl L(-1)). Leaves of plants irrigated with 240 mmol NaCl L(-1) became chlorotic after 30 days exposure. However, concentrations of N, P. Mg and Zn in leaves were not affected significantly (P > 0.05) by salinity. Apparently, K(+) and Ca(2+) were the key nutrients affected in the response of carob rootstocks to salinity. Plants grown with 80 and 120 mmol L(-1) of NaCl contained the greatest K. concentration. Na(+)/K(+) increased with salinity, due to an elevated Na(+) content but K(+) uptake was also enhanced, which alleviated some Na. stress. Ca(2+) concentration in leaves was not reduced under salinity. Salinization of irrigation water and subsequent impacts on agricultural soils are now common problems in the Mediterranean region. Under such conditions, carob seems to be a salt as well as a drought tolerant species. (C) 2010 Elsevier B.V. All rights reserved.

The effect of stress on egg quality in farmed Atlantic Cod (Gadus morhua L.)

Dissertação de mestrado, Aquacultura, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2011