Percorrer por autor "Vasconcelos, Marta W."
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- A água e a nutrição-veículo deinteracção com o HomemPublication . Vasconcelos, Marta W.; Malcata, F. Xavier
- Alimentos transgénicosPublication . Vasconcelos, Marta W.
- Anti-inflammatory and metabolic effects of lentil phenolic compoundsPublication . Geraldo, Rafaela; Gouveia, Alexandra; Neves, Delminda; Freitas, Victor; Pinto, Elisabete; Vasconcelos, Marta W.
- Antimicrobial potential of six plant essential oils against Pseudomonas syringae pv. actinidiae: in vitro activity and in planta efficacy do not always alignPublication . Silva, Marta Nunes da; Santos, Miguel G.; Vasconcelos, Marta W.; Carvalho, Susana M. P.Plant essential oils (EOs) are attracting interest as ecofriendly alternatives to antibiotics and copper-based control of kiwifruit bacterial canker (KBC), caused by Pseudomonas syringae pv. actinidiae (Psa). This study chemically profiled six EOs (anise, basil, cardamom, cumin, fennel, and laurel) and evaluated their antimicrobial activity both in vitro and in planta. The in vitro assay targeted four strains, two of Psa and two of the low-virulent P. syringae pv. actinidifoliorum (Pfm), whereas the in planta assay focused on the highly virulent Psa7286 strain, assessed under preventive and curative application regimes (i.e., 14 days pre- or post-inoculation, respectively). Cumin, with cuminaldehyde as its major component (48%), was the most effective EO in vitro, significantly inhibiting growth at 5–10% concentration, whereas anise, rich in anethole (89%), was consistently the least effective one. However, the in planta application of the EOs produced antimicrobial effects that differed markedly from in vitro results and showed strong dependence on the timing of application. Preventive treatment significantly reduced Psa endophytic populations in basil (70%), anise (54%), laurel (42%), and cumin (35%) compared to untreated plants. In contrast, when the EOs were applied post-inoculation (curative treatment), a significant decrease in Psa colonization was observed in laurel (81%), cardamon (70%), cumin (31%) and fennel (29%). Although plant EOs are gaining momentum in the control of Psa and other diseases, translation from in vitro to in planta efficacy is not direct and is strongly timing-dependent, which underscores the need to perform validation trials in planta and to fine-tune application schedules for the integrated management of KBC.
- Are there any Pinus pinaster trees resistant to Bursaphelenchus xylophilus? Studies implemented in Portugal to address this questionPublication . Costa, R.; Ribeiro, P.; Evaristo, I.; Ribeiro, B.; Aguiar, A.; Carrasquinho, I.; Santos, C.; Vasconcelos, Marta W.
- Assessing the effectiveness of different Pseudomonas syringae pv. actinidiae pre-inoculation procedures to promoting disease visual symptoms in adult kiwifruit plantsPublication . Santos, Miguel G.; Silva, Marta Nunes da; Gallego, Pedro P.; Vasconcelos, Marta W.; Carvalho, Susana M. P.
- Assessing the potential of a sustainable bean leaf extract with abscisic acid in pear ripening restorationPublication . Dias, Cindy; Sousa, Clara; Ferrante, António; Pintado, Manuela; Vasconcelos, Marta W.Introduction: Rocha pear (Pyrus communis L. cv Rocha) is a Portuguese cultivar stored with 1-MCP in controlled atmosphere to extend storage life and prevent postharvest issues. However, 1-MCP obstructs the normal ripening, impacting pear quality for consumers. Several strategies have been applied to reboot the ripening of pear under 1-MCP effect, such as the application of higher temperatures, exogenous ethylene or a combination of both. However, these treatments demand high energy consumption. Some phytohormones, like abscisic acid (ABA), have been shown to accelerate ripening by stimulating ethylene production, firmness loss, coloring, among other ripening markers. Objective: In this study, leaves from bean plants derived from agri-food wastes were explored to extract phytohormones with focus on ABA, using a sustainable approach. Further the study aimed to investigate the potential of this green extract as a ripening inducer for pears under the 1-MCP effect. Time course physiological and biochemical analysis comparison with ‘Rocha’ pear treated with synthetic ABA was performed. Conclusions: The extraction approach developed in this study extracted ABA from bean leaves using only water under cold conditions. This suggests a sustainable approach by repurposing agricultural by-products; Bean leaves extract and synthetic ABA treatment of pears, under the influence of 1-MCP, resulted in increased respiration and ethylene production after 15 days. This was accompanied by higher SSC, color and firmness loss suggesting that ABA may be inducing the ripening process; Evaluating natural and synthetic ABA on pear ripening is essential to determine the effectiveness of the natural source relative to the conventional synthetic version. Despite lower ABA concentration in the natural extract, similar responses to synthetic ABA suggest the involvement of not only ABA but other bioactive compounds; The results of this study could have implications for the development of eco-friendly and sustainable practices in agri-food waste utilization and fruit post-harvest management.
- Avaliação da susceptibilidade da flora autóctone Portuguesa ao nemátode da madeira do pinheiro (Bursaphelechus xylophilus)Publication . Silva, Marta A. N.; Lima, Marta R. M.; Vasconcelos, Marta W.
- Avaliação dos efeitos da aplicação de micorrizas ericóides no crescimento de mirtilo (Vaccinium corymbosum L.)Publication . Gonçalves, Patrícia A. F.; Silva, M. A. Nunes da; Machado, Joana; Carvalho, Susana M.P.; Vasconcelos, Marta W.O mirtilo (Vaccinium corymbosum L.) apresenta um sistema radicular muito superficial e compacto, sem pêlos radiculares. Como tal, estas plantas tendem a estabelecer simbiose com fungos ericóides micorrízicos (FEM), o que lhes permite aumentar a absorção de nutrientes e água. Como a colonização natural é frequentemente reduzida e dependente da cultivar e das práticas agronómicas, a inoculação externa com fungos micorrízicos tem vindo a ser utilizada pelos viveiristas para aumentar a taxa de fungos simbiontes. Contudo, a relação planta/fungos ericóides está ainda pouco estudada e o modo como estes microsimbiontes melhoram o crescimento e a nutrição do mirtilo necessita de ser elucidado. Neste estudo, foram inoculadas duas cultivares de mirtilo (‘Aurora’ e ‘Duke’) com uma mistura comercial de FEM. Cerca de 14 meses após inoculação foi avaliada a taxa de colonização das raízes e foram registados vários parâmetros biométricos (peso seco, altura da planta, diâmetro do caule e comprimento da raíz), fisiológicos (teor de clorofila das folhas) e nutricionais (concentração de minerais inorgânicos) em plantas submetidas a tratamento com inóculo e plantas controlo. Os resultados obtidos demonstraram que a percentagem de peso fresco das raízes naturalmente colonizada por fungos ericóides foi aproximadamente 30 % para ambas as cultivares (plantas controlo), aumentando para 56 % na ‘Aurora’ e para 44 % na ‘Duke’ em plantas inoculadas com mistura de FEM. Nas plantas inoculadas da cv. ‘Aurora’, observou-se um aumento significativo do peso seco total das raízes (48 %) e dos caules (31 %) comparativamente às plantas controlo. Paralelamente, também se verificou um aumento significativo da altura das plantas e do comprimento das raízes. Já na cv. ‘Duke’ o efeito da inoculação não foi significativo em nenhum dos parâmetros biométricos estudados. A inoculação induziu a acumulação de Mo nas raízes e de K nos caules e folhas na cv. ‘Aurora’, e aumentou a concentração de Mn, Fe e Cu nas raízes e caules (em alguns casos por 280 %) na cv. ‘Duke’. A inoculação de plantas de mirtilo com fungos ericóides tem um potencial evidente no estímulo do crescimento das plantas e absorção de nutrientes; no entanto, a sua eficácia parece estar dependente da cultivar.
- Biochemical basis of CO2-related internal browning disorders in pears (Pyrus communisL. cv. Rocha) during long-term storagePublication . Deuchande, Teresa; Larrigaudière, Christian; Giné-Bordonaba, Jordi; Carvalho, Susana; Vasconcelos, Marta W.This study aimed at understanding the biochemical basis of internal browning disorders (IBDs) in 'Rocha' pear. For this purpose, the effects of storage under normal controlled atmosphere (CA) (3 kPa of O2 + 0.5 kPa of CO2) and IBD-inducing CA (1 kPa of O2 + 10 kPa of CO2) on the antioxidant and fermentative metabolisms and polyphenol oxidase (PPO) activity and phenolics concentration were studied. The higher IBD incidence in high CO2-stored fruits was positively correlated with fermentative metabolites and negatively with ascorbate and H2O2 concentrations, and it was linked to PPO activation. These results indicate that both the antioxidant and fermentative metabolisms are involved in the occurrence of IBD in 'Rocha' pear. From the integration of the biochemical and enzymatic data, a schematic model illustrating the effects of high CO2 and low O2 in 'Rocha' pears during long-term storage was constructed.