Untitled

Funder

Organizational Unit

Publications

Soil and foliar applied boron in olive: Tree crop growth and yield, and boron remobilization within plant tissues

Publication . Ferreira, Isabel Q.; Rodrigues, M.A.; Arrobas, Margarida

Boron (B) has great importance in the fertilizer recommendation programs of olive, since B deficiency is a frequent nutritional disorder. This paper reports results of the olive response to applied B from two 3-year field trials (ExpF1, ExpF2) and two pot experiments (ExpP1, ExpP2). The ExpF1 was installed in a 3-year-old orchard and the ExpF2 consisted of planting young trees with the aboveground biomass yield being recorded. In ExpP1, B was applied to the soil or as a foliar spray to the whole of the canopy. The ExpP2 consisted of the application of B to selected parts of the canopy. The concentration of B in the existing tissues receiving the spray directly and in the new shoots developing after the B application was determined. The performance of the crop, including olive yield, did not increase in ExpF1 with soil-applied B. However, dry matter yield of young plants in ExpF2 significantly increased with B application. The application of B, both as a soil fertilizer and as a foliar spray, significantly increased the B concentration in all tissues and in all experiments. From ExpP1, soil applied B proved to be a more powerful tool of delivering high amounts of B to the plant than foliar spray. From ExpP2, B was shown to be mobile in the tree to some extent, although the mobility appears to be cultivar-dependent. In 'Arbequina' the older leaves that received the foliar spray showed higher B levels than the young leaves that developed thereafter, whereas in 'Cobrançosa' this difference was not observed.

2019Journal article

Open access

Caracterização nutricional e propriedades bioativas de Geranium robertianum L.: da planta à fração mais bioativa

Publication . Graça, Vânia C.; Barros, Lillian; Calhelha, Ricardo C.; Dias, Maria Inês; Carvalho, Ana Maria; Santos-Buelga, Celestino; Santos, Paulo F.; Ferreira, Isabel C.F.R.

Geranium robertianum L., vulgarmente conhecida como Erva de São Roberto, é uma planta pertencente à família Geraniaceae utilizada em medicina popular no tratamento de uma variedade alargada de doenças [1]. Embora as propriedades terapêuticas tornem esta espécie muito apreciada, estudos sistemáticos da sua composição fitoquímica e bioatividade são ainda escassos. No presente trabalho foram caracterizadas amostras silvestres de G. robertianum provenientes de Trásos- Montes, Portugal, quanto à sua composição centesimal - proteínas, gorduras, hidratos de carbono e cinzas - bem como em açúcares livres, ácidos orgânicos, ácidos gordos e tocoferóis. A infusão e a decocção (formas comuns de consumo desta planta) e diferentes frações orgânicas, obtidas por extração sequencial, foram avaliadas e comparadas quanto à sua atividade antioxidante (capacidade de captação de radicais livres, poder redutor e inibição da peroxidação lipídica) e citotoxicidade em várias linhas celulares tumorais humanas (MCF-7, NCI-H460, HeLa e HepG2) e numa cultura de células primárias de fígado de porco (não tumorais). Foi ainda determinado, por HPLC-DAD-ESI/MS, o perfil de compostos fenólicos da fração mais bioativa. G. robertianum demonstrou ser uma planta mais abundante em hidratos de carbono e proteínas e pobre em gordura, proporcionando açúcares, tocoferóis, ácidos orgânicos e ácidos gordos essenciais. A fração de acetona apresentou o maior teor de fenóis e flavonóides totais, bem como as maiores atividades antioxidante e citotóxica. Esta fração mostrou conter taninos hidrolisáveis como principais compostos fenólicos. Este trabalho, detalhado numa publicação recente dos autores [2], visa, juntamente com a presente comunicação, recuperar e valorizar a utilização tradicional desta planta

2016Conference object

Open access

The effects of long-term chaetomellic acid a administration on renal function and oxidative stress in a rat model of renal mass reduction

Publication . Nogueira, António José M.; Peixoto, Francisco P.; Oliveira, Maria Manuel; Pires, Carlos André; Colaço, Bruno Jorge; Oliveira, Paula A.; Pires, Maria João

This study aimed to evaluate the effect of chronic treatment with chaetomellic acid A (CAA) on oxidative stress and renal function in amodel of renalmass reduction. Methods.MaleWistar ratswere subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after surgery, rats have been divided into four experimental groups: RMR: RMR rats without treatment (n = 14); RMR + CAA: RMR rats treated with CAA (n = 13); SO: SO rats without treatment (n = 13); and SO + CAA: SO rats treated with CAA (n = 13). CAA was intraperitoneally administered in a dose of 0.23 μg/Kg three times a week for six months. Results. RMR was accompanied by a significant reduction in catalase and glutathione reductase (GR) activity (p < 0.05) and a decrease in reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio. CAAadministration significantly increased catalase andGR activity (p < 0.05) and increased GSH/GSSG ratio, but no significant difference between the treated and nontreated groups was found in this ratio.No significant differences were found between theRMRgroups in any of the parameters of renal function.However, CAA administration slightly improves some parameters of renal function. Conclusions. These data suggest that CAA could attenuate 5/6 RMR-induced oxidative stress.

2017Journal article

Open access

Ultrasonographic evaluation of the kidney in 5/6 nephrectomized rats: Correlation with biochemical and histopathological findings

Publication . Nogueira, António José M.; Rocha, Ana Isabel Faustino; Ginja, Mário; Oliveira, Paula A.; Pires, Maria João

To characterize the kidney alterations associated with renal mass reduction by two-dimensional ultrasound and assess the correlation of the ultrasonographic parameters with the histological and biochemical findings. Materials and Methods: Rats were divided into two groups: sham-operated animals (n=13), and animals which underwent renal mass reduction (RMR) through 5/6 nephrectomy (n=14). Renal length, renal thickness, cortical thickness, medullary length and echogenicity of the kidneys were evaluated by ultrasonography at 3 and 6 months after the RMR. Results: Except for the renal length, the renal dimensions at 3 and 6 months were significantly higher in the RMR group when compared to the sham-operated group (p < 0.05). Furthermore, the cortical and medullary echogenicity was significantly higher in the RMR group when compared to the sham-operated group (p < 0.05). A significant correlation was observed between the plasma creatinine level and the renal length 3 months after RMR (r=-0.612, p=0.045). Conclusion: These data support future application of ultrasonography for monitoring the progression of renal damage in chronic studies with the 5/6 nephrectomy model.

2016Journal article

Open access

Repulsive effect of stroboscopic light barriers on native salmonid (Salmo trutta) and cyprinid (Pseudochondrostoma duriense and Luciobarbus bocagei) species of iberia

Publication . Jesus, Joaquim; Teixeira, Amílcar; Natário, Silvestre; Cortes, Rui M.V.

A repulsive effect, that some induced primary stimuli, like sound and light, is known to be provoked in fish behavior. In the present study, two strobe light frequencies, 350 flashes/minute and 600 flashes/minute, were tested in laboratorial conditions, using three native freshwater fish species of northern Portugal: Brown trout (Salmo trutta), Northern straight-mouth nase (Pseudochondrostoma duriense) and Iberian barbel (Luciobarbus bocagei). The results showed a differential repulsive behavior of the fish species to light stimulus, and particularly to a frequency of 600 flashes/minute. S. trutta presented the most repulsive behavior, whereas the L. bocagei showed less repulsion to the light stimulus. No relevant differences were found between pre-test and post-assessments, confirming a rapid recovery of natural fish behavior after the deterrent effect. The results highlighted the potential of behavioral barriers, particularly in salmonid streams, based on strobe light stimulus.

2019Journal article

Open access