Cancro bacteriano do kiwi: novas estratégias de mitigação para um velho problema

Este trabalho, realizado no âmbito de uma tese de doutoramento levada a cabo na Faculdade de Ciências da Universidade do Porto, conclui que a fertilização azotada à base de nitrato pode ser uma ferramenta útil para aumentar a tolerância das plantas de kiwi contra a bactéria Pseudomonas syringae pv. Actinidiae (Psa) e que alguns óleos essenciais de plantas têm potencial para inclusão numa estratégia mais sustentável de gestão da doença.info:eu-repo/semantics/publishedVersio

Evaluation of plant elicitation with methyl-jasmonate, salicylic acid and benzo (1,2,3)-thiadiazole-7-carbothioic acid-S-methyl ester for the sustainable management of the pine wilt disease

Treatment with plant elicitors can be a promising method to induce Pinus pinaster tolerance against the pinewood nematode (PWN), Bursaphelenchus xylophilus, by promoting plant antioxidant system, micronutrient accumulation and by modulating plant-associated bacterial populations. To test this hypothesis, plants were sprayed with methyl jasmonate (MeJA), salicylic acid (SA) or benzo (1,2,3)-thiadiazole-7-carbothioic acid-S-methyl ester (BTH), and evaluated until 35 days after-inoculation (dai) for: i) extent of foliar symptoms; ii) nematode density inside stem tissues; iii) proxies for oxidative damage and antioxidant activity, iv) micronutrient concentration and v) bacterial diversity. Compared with non-elicited plants, plant elicitation, particularly with BTH, significantly decreased nematodes density inside stem tissues (by 0.63-fold). Concordantly, without elicitation plant mortality reached 12.5% while no mortality was observed in elicited plants. BTH-elicited plants had significantly higher concentrations of anthocyanins and carotenoids at the end of the assay than SA-elicited and MeJA-elicited plants, which possibly contributed to the lower PWN colonization and degree of foliar symptoms observed. Accordingly, MeJA and SA led to increased lipid peroxidation at 28 dai (by 2.64- and 2.52-fold, respectively) in comparison with BTH (by 1.10-fold), corroborating its higher potential in increasing plant antioxidative response during infection. Moreover, carotenoids showed a negative correlation with nematode migration, whereas polyphenols showed a positive correlation. Elicitors also induced changes in the bacterial community of infected P. pinaster plants, increasing the diversity of specific populations. Finally, elicitors induced significant changes in micronutrients accumulation in plant tissues, namely a decrease in the concentration of B, Mn and Ni in plants treated with BTH compared to those treated with the other elicitors. Altogether, results suggest that elicitation with MeJA, SA and, particularly, BTH, increases tolerance against B. xylophilus by promoting plant antioxidant system, changing the accumulation of essential micronutrients and modulating plant-associated bacterial diversity.info:eu-repo/semantics/publishedVersio

Papel dos ácidos húmicos na mineralização do azoto em solos florestais

Mestrado em Química Analítica e Controlo de QualidadeNeste trabalho extraíram-se ácido húmicos de seis amostras de solos florestais com características distintas. Os ácidos húmicos foram caracterizados por análise elementar, espectroscopia de UV-Vis, espectrometria de FT-IR, espectrometria de fluorescência molecular e espectrometria de RMN de 13C. O estudo dos ácidos húmicos foi efectuado numa tentativa de se encontrarem características que se relacionassem com a taxa de mineralização do azoto nos solos. Verificou-se que a taxa de mineralização do azoto nos solos é superior naqueles que possuem maior teor de ácidos húmicos. Foi também possível averiguar que provavelmente os grupos funcionais dos ácidos húmicos que mais contribuem para a mineralização do azoto são estruturas aromáticas às quais o azoto se encontra acoplado. Estruturas mais humificadas são menos susceptíveis de sofrer degradação, no entanto não se verificou qualquer tipo de relação entre o grau de humificação da matéria e a taxa de mineralização do azoto no solo. ABSTRACT: In this work humic acids were extracted from six samples of forests soils. The humic acids were characterized by elemental analysis, Ultraviolet-Visible spectroscopy, FT-IR spectroscopy, molecular fluorescence spectroscopy and solid state 13C-NMR. The aim of study of humic acids was to found characteristics that could be related with the rate of mineralisation of nitrogen in forests soils. The results showed that the rate of mineralisation of nitrogen in soils is bigger on that ones that have a superior content of humic acids. It was also possible to found that the functional groups that are more relevant to the mineralisation process are aromatic structures were nitrogen is. Older humic compounds are less susceptible to degradation. However it was not found any correlation between humification index of organic matter with the rate of mineralisation of nitrogen in forests soils

Mineral profile and resilience to low water provision of white and black chickpea varieties (Cicer arietinum)

Legumes are of great importance for agriculture and the environment due to their ability to fix atmospheric nitrogen, providing important amounts of minerals, and vitamins, being are an excellent option for a balanced diet (Geraldo et al., 2022). Among the most consumed legumes worldwide, chickpeas (Cicer arietinum) have gained evidence in these past decades, through increased individual production, intercropping with other crops, and formulation of food products, thus improving the resilience of agroecosystems at lower environmental costs (Saget et al., 2020). However, the exploitation of traditional chickpea varieties, such as the black chickpea, has been overlooked, and the recovery of under-exploited traditional varieties could contribute to foster biodiversity, promote environmental sustainability and diversify diets. However, current knowledge on the nutritional profile of commercial and traditional chickpea varieties and their resilience to environmental stresses, such as water scarcity, is very limited, being the focus of this work.info:eu-repo/semantics/publishedVersio

Differential responses of Kabuli and Desi chickpeas (Cicer arietinum) to low water provision and their mineral profiling

Legume grains are of great importance for agriculture and the environment due to their ability to symbiotically fix atmospheric nitrogen and provide protein, minerals, vitamins, and other bioactive nutrients (Geraldo et al., 2022). Chickpea (Cicer arietinum) is one of the most consumed legumes worldwide and it has gained even more importance in recent decades. Production levels have increased, their incorporation as intercrops has been promoted, and they have been used in the formulation of novel food products (Saget et al., 2020). Nonetheless, the exploitation of traditional chickpea varieties, such as the Desi type (black coloured chickpea), has been overlooked, and the recovery of under-exploited traditional varieties could contribute to fostering biodiversity, and promoting environmental sustainability and diversifying diets. However, current knowledge on the nutritional profile of commercial and traditional chickpea varieties and their resilience degree to environmental stresses, such as water scarcity, is limited, thus being the focus of this work.info:eu-repo/semantics/publishedVersio

Para toda a vida ou por uma só noite? Estudo descritivo sobre as diferenças de género nas atitudes sexuais

Dissertação de Mestrado apresentada ao Instituto Superior de Psicologia Aplicada para obtenção de grau de Mestre na especialidade de Psicologia Clínica.As atitudes sexuais têm vindo a ser um tema de estudo abordado por diversos autores. Grande parte dos estudos apontam para uma diferença entre os géneros nas atitudes sexuais. As mulheres tendem a valorizar mais a parte afectiva e relacional, enquanto que os homens tendem a ser mais permissivos e a dar mais ênfase ao envolvimento físico. Este estudo pretendeu analisar quais as diferenças entre os géneros ao nível das atitudes sexuais, focando a sua relação com alguns comportamentos sexuais e outras variáveis sócio-demograficas. Trata-se de um estudo descritivo transversal e comparativo com uma amostra de 510 sujeitos, dos quais 201 são homens e 309 são mulheres. Procedeu-se à recolha de dados através de questionários anónimos de auto-resposta, incluindo um sócio-demográfico, um questionário sobre comportamentos sexuais e a Escala Breve de Atitudes Sexuais de Hendrick & Hendrick (2006). Os resultados confirmaram que existem diferenças nas atitudes sexuais entre os géneros. Factores como a idade, religião e meio habitacional parecem também exercer alguma influência nas atitudes e comportamentos sexuais. Assim, concluímos que as mulheres têm menos parceiros sexuais e dão maior ênfase ao afecto numa relação sexual, ao passo que os homens têm mais relações sexuais ocasionais e atitudes mais permissivas.ABSTRACT: Sexual attitudes have been a subject studied by several authors. Most of the studies say that there are gender differences in sexual attitudes. Women tend to enhance more the sentimental and relational part, while men are more permissive and give more emphasis to physical involvement. This study analysed which are the differences between both genders in sexual attitudes, focusing their relationship with some sexual behaviours and other social and demographic variables. It is a descriptive, transversal and comparative study with a total sample of 510 people, 201 men and 309 women. We used anonymous self-response questionnaires, including a social-demographic, a questionnaire of sexual behaviour and the Brief Sexual Attitudes Scale (Hendrick & Hendrick, 2006). The results confirmed that there are gender differences in sexual attitudes. We also found some influences of age, religion and living place in sexual attitudes and sexual behaviours. Thus, we conclude that women have less sexual partners and give more importance to affective issues in a sexual relationship, while men have more casual sex and more permissive attitudes

Mitigation of emergent bacterial pathogens using pseudomonas syringae pv. Actinidiae as a case study — from orchard to gene and everything in between

Globalization propelled human migration and commercial exchanges at the global level, but woefully led to the introduction of non-indigenous organisms into several agroecological systems. These include pathogenic bacteria with devastating consequences for numerous crops of agronomical importance for food production worldwide. In the last decade, research efforts have focused on these noxious organisms, aiming to understand their evolutionary processes, degree of pathogenicity, and mitigation strategies, which have allowed stakeholders and policymakers to develop evidence-based regulatory norms to improve management practices and minimize production losses. One of these cases is the bacterium Pseudomonas syringae pv. actinidiae (Psa), the causal agent of the kiwifruit bacterial canker, which has been causing drastic production losses and added costs related to orchard management in the kiwifruit industry. Although Psa is presently considered a pandemic pathogen and far from being eradicated, the implementation of strict regulatory norms and the efforts employed by the scientific community allowed the mitigation, to some extent, of its negative impacts through an integrated pest management approach. This included implementing directive guidelines, modifying cultural practices, and searching for sources of plant resistance. However, bacterial pathogens often have high spatial and temporal variability, with new strains constantly arising through mutation, recombination, and gene flow, posing constant pressure to agroecosystems. This review aims to critically appraise the efforts developed to mitigate bacterial pathogens of agronomical impact, from orchard management to genome analysis, using Psa as a case study, which could allow a prompter response against emerging pathogens in agroecosystems worldwide.info:eu-repo/semantics/publishedVersio

Scientific and technological advances in the development of sustainable disease management tools: a case study on kiwifruit bacterial canker

Plant disease outbreaks are increasing in a world facing climate change and globalized markets, representing a serious threat to food security. Kiwifruit Bacterial Canker (KBC), caused by the bacterium Pseudomonas syringae pv. actinidiae (Psa), was selected as a case study for being an example of a pandemic disease that severely impacted crop production, leading to huge economic losses, and for the effort that has been made to control this disease. This review provides an in-depth and critical analysis on the scientific progress made for developing alternative tools for sustainable KBC management. Their status in terms of technological maturity is discussed and a set of opportunities and threats are also presented. The gradual replacement of susceptible kiwifruit cultivars, with more tolerant ones, significantly reduced KBC incidence and was a major milestone for Psa containment – which highlights the importance of plant breeding. Nonetheless, this is a very laborious process. Moreover, the potential threat of Psa evolving to more virulent biovars, or resistant lineages to existing control methods, strengthens the need of keep on exploring effective and more environmentally friendly tools for KBC management. Currently, plant elicitors and beneficial fungi and bacteria are already being used in the field with some degree of success. Precision agriculture technologies, for improving early disease detection and preventing pathogen dispersal, are also being developed and optimized. These include hyperspectral technologies and forecast models for Psa risk assessment, with the latter being slightly more advanced in terms of technological maturity. Additionally, plant protection products based on innovative formulations with molecules with antibacterial activity against Psa (e.g., essential oils, phages and antimicrobial peptides) have been validated primarily in laboratory trials and with few compounds already reaching field application. The lessons learned with this pandemic disease, and the acquired scientific and technological knowledge, can be of importance for sustainably managing other plant diseases and handling future pandemic outbreaks.info:eu-repo/semantics/publishedVersio

A pertinência das tecnologias da informação e comunicação nas experiências de aprendizagem em história e geografia

Orientação: José DuarteNo mundo atual, as Tecnologias da Informação e Comunicação revelam-se o instrumento central de gestão dos conteúdos, auxiliando o trabalho docente e ajudando os alunos a construir o seu conhecimento e, consequentemente, levando-os a compreender criticamente a realidade que os rodeia, a sociedade da informação e do conhecimento. A utilização destas ferramentas possibilita criar/ inovar alternativas didáticas capazes de operar verdadeiros processos de mudança, motivando e estimulando os alunos para aprendizagens mais significativas. Se bem que todas as áreas do saber devem experimentar novos métodos e experiências de aprendizagem, a História e a Geografia são campos profícuos para a utilização de metodologias de recurso às TIC, âmbito ainda pouco desenvolvido no que toca o Currículo Nacional do Ensino Básico. Mais, existe muito ceticismo entre os professores, pelo que o uso destes instrumentos é renegado e subaproveitado, utilizando-se exaustivamente os recursos clássicos, cujos resultados e margem de erro são já amplamente conhecidos e justificados. O presente estudo, desenvolvido no âmbito da dissertação de mestrado em ensino da História e Geografia ao 3º ciclo do ensino básico e secundário, visa ser uma reflexão sobre a forma como as TIC estão atualmente integradas no contexto educativo, alertando para a necessidade de encetar verdadeiras transformações que moldem a escola às exigências da sociedade atual. Num contexto limitado ao cenário do estágio curricular, o objetivo deste trabalho é verificar a utilização das TIC no processo de ensino e aprendizagem, analisando a representação que os alunos e professores têm desta prática. Os resultados deste estudo vão demonstrar que a utilização efetiva das TIC está aquém das suas potencialidades, ilustrando-se alguns dos motivos deste facto.In today's world, the Information and Communication Technologies reveal themselves as a key instrument for managing the programmatic contents, assisting the teaching practice and helping students build their own knowledge and, consequently, causing them to critically understand the surrounding reality, the information society. The use of these tools allows you to create innovating teaching alternatives, operating real changing processes, motivating and encouraging students to a meaningful learning. Although all areas of knowledge should try new methods and learning experiences, history and geography are fruitful fields for the use of methodologies using ICT, an area undeveloped in the Basic Education National Curriculum. More, there is much skepticism among teachers, so the use of these instruments is renegade and underused, exhaustively using classical resources, where the outcomes and margins of error are already widely known and justified. This study, developed in the context of a master’s degree dissertation, aims to be a reflection on how ICTs are currently integrated in the educational system, stressing the need to engage in true transformations that will shape the school to the demands of the contemporary society. In the limited context of the curricular internship, this study’s objective is to assess the use of ICT in the teaching and learning process, analyzing students and teachers representations on this matter. The results of this study will demonstrate that the effective use of ICT is below potential, illustrating a few of the reasons for this fact