http://hdl.handle.net/10174/1019 2026-07-31T20:50:25Z http://hdl.handle.net/10174/41736 Title: Walnut Shells to Enhance Substrate Sustainability: Effects on Lettuce Yield, Nitrate Accumulation, and Phytochemical Content. Authors: Machado, Rui; Alves-Pereira, Isabel; Grilo, Ana; Esteves, Pedro; Rui, Ferreira Abstract: Coir is widely used as a soilless substrate yet partially replacing it with walnut shells in coir-based mixes may improve the sustainability of lettuce production and quality. This study evaluated the effect of incorporating walnut shells, with or without biochar, into coir-based substrates on lettuce yield and quality. Lettuce was grown in five substrates: coir (C), three coir–walnut mixes (1:1, 1:0.5, and 1:0.25 v/v), and one coir–walnut–biochar mix (C:W:B, 10:1.5:1 v/v). Increasing the walnut-shell proportion increased the cumulative leaching fraction, likely because of the coarse walnut particles, and reduced head fresh weight. However, shoot dry weight in the 1:0.5 and 1:0.25 mixes was similar to that in coir alone and reduced leaf nitrate content. In contrast, the C:W:B mix maintained head fresh weight (7.1 kg m→2) and shoot dry weight comparable to coir, while markedly lowering leaf nitrate concentration from 4130 to below 200 mg NO3→ kg→1 fresh weight. Leaf nitrate content increased linearly with shoot Zn uptake, suggesting a Zn-mediated control of nitrate accumulation. The coir–walnut–biochar mix emerges as a suitable alternative to pure coir, as it maintains lettuce productivity, reduces leaf nitrate accumulation, enhances anthocyanin content, and reflects more favorable physiological conditions by not requiring a strong activation of antioxidant defenses. 2026-01-07T00:00:00Z http://hdl.handle.net/10174/41674 Title: First Report on the Synergistic Interaction between Essential Oils against the Pinewood Nematode Bursaphelenchus xylophilus Authors: Jorge M. S. Faria, Tomás Cavaco; Pedro Barbosa, Dora Martins Teixeira; Maria L. Inácio Abstract: Control of the pinewood nematode (PWN), the causal agent of pine wilt disease, can be achieved through the trunk injection of nematicides; however, many pesticides have been linked to environmental and human health concerns. Essential oils (EOs) are suitable alternatives due to their biodegradability and low toxicity to mammals. These complex mixtures of plant volatiles often display multiple biological activities and synergistic interactions between their compounds. The present work profiled the toxicity of eight EOs against the PWN in comparison to their 1:1 mixtures, to screen for successful synergistic interactions. Additionally, the main compounds of the most synergistic mixtures were characterized for their predicted environmental fate and toxicity to mammals in comparison to emamectin benzoate, a commercial nematicide used against PWN. The mixtures of Cymbopogon citratus with Mentha piperita and of Foeniculum vulgare with Satureja montana EOs showed the highest activities, with half-maximal effective concentrations (EC50) of 0.09 and 0.05 L/mL, respectively. For these, complete PWN mortality was reached after only ca. 15 min or 2 h of direct contact, respectively. Their major compounds had a higher predicted affinity to air and water environmental compartments and are reported to have very low toxicity to mammals, with low acute oral and dermal toxicities. In comparison, emamectin benzoate showed lower nematicidal activity, a higher affinity to the soil and sediments environmental compartments and higher reported oral and dermal toxicity to mammals. Overall, uncovering synergistic activities in combinations of EOs from plants of different families may prove to be a source of biopesticides with optimized toxicity against PWNs. 2023-01-01T00:00:00Z http://hdl.handle.net/10174/41672 Title: Infection of In Vivo and In Vitro Pines with the Pinewood Nematode Bursaphelenchus xylophilus and Isolation of Induced Volatiles Authors: Faria, Jorge M. S.; Figueiredo, A. Cristina; Teixeira, Dora M.; Inácio, Maria L. Abstract: The pinewood nematode (PWN) is a phytoparasite that causes pine wilt disease (PWD) in conifer species. This plant parasitic nematode has heavily contributed to pine deforestation in Asian countries, e.g., Japan, China, and Korea. Over the last two decades, in Europe, Portugal and Spain have been greatly affected. Research on the mechanisms of PWN infection and/or PWD progression in susceptible host species relies on the controlled infection of pine seedlings under greenhouse conditions. This technique is laborious and mobilizes substantial economic and human resources. Additionally, it can be prone to variability that results from the genetic diversity associated with some pine species but also from the interference of external factors. As an alternative, in vitro co-cultures of pine with PWNs offer a more advantageous system for studying biochemical changes since they a) allow controlling single environmental or nutritional variables, b) occupy less space, c) require less time to obtain, and d) are free from contamination or from host genetic variation. The following protocol details the standard in vivo PWN infection of Pinus pinaster, the maritime pine, and the establishment of the novel in vitro co-cultures of pine shoots with the PWN as an improved methodology to study this phytoparasite influence on pine volatiles. PWN-induced volatiles are extracted from in vivo and in vitro infected pines by hydrodistillation and distillation-extraction, and the emitted volatiles are captured by solid phase microextraction (SPME), using fiber or packed column techniques. © 2024 JoVE Journal of Visualized Experiments. 2024-08-31T23:00:00Z http://hdl.handle.net/10174/40736 Title: From Ink to Mockup: An Integrated Study of Historical Gall Ink Formulations and Their Impact on Paper Authors: Nunes, Margarida; Vieira, Joana C.; Costa, Ana Paula; Cabral, Maria Emilia A.; Vieira, Bruno J.C.; Waerenborgh, João Carlos; Nogueira, Isabel I.S.; Mitchell, Scott G.; Claro, Ana; Ferreira, Teresa Abstract: Iron gall inks (IGIs) played a central role as a writing medium in Western countries, leaving behind a vast legacy and significant conservation challenges. This study presents a twofold methodological approach to investigate the physicochemical behaviour of IGI-based formulations found in historical Portuguese sources. Fresh and 6-month naturally aged precipitates and supernatant solutions (dried inks) were characterised, and the impact of IGIs on Whatman paper over ageing was studied using attenuated total reflectance Fourier-transform infrared (ATR-FT-IR) spectroscopy, Raman and Mössbauer spectroscopies and X-ray diffraction (XRD). Iron(II) sulphates comprised the primary crystalline phase in the precipitates, while the dried inks consisted of distinct Fe(III)-polyphenol (PPh) complexes. Over time, Fe(III) Mössbauer parameters supported complex structural alterations. IGI-induced degradation on aged mockups was attested by Fe(II) oxalate formation until total depletion of the Fe(III)-PPh fraction. pH, ATR-FT-IR and degree of polymerisation analyses suggested that cellulose oxidation is the primary degradation mechanism, and the physical properties and XRD corroborated that the cellulose structure became disordered over ageing. The ink with the higher weight ratio of Fe(II) sulphate:gallnuts (unbalanced) exhibited the most aggressive action on the support. The results confirm that the more unbalanced the ink composition, the more severe its impact, with ink concentration per surface area also being a critical factor in paper decay. 2026-01-30T00:00:00Z