Browsing by Author "Correia, Pedro José"
Now showing 1 - 10 of 24
Results Per Page
Sort Options
- Brief characterisation of Fe chlorosis in chia (Salvia hispanica L.) plants grown in nutrient solutionPublication . Vieira, João; Džidić Uzelac, Luna; Thais Fidelis Alves, Izabela; Patrício, Marco; Gama, Florinda; Saavedra, Teresa; Correia, Pedro José; Pestana, MaribelaChia (Salvia hispanica L.) plant is a well-known plant due to the nutraceutical value of its seeds. The aim of this preliminary study was to assess the response of Chia plants to Fe deficiency. Chia plants were grown for 12 days in Hoagland's nutrient solutions without Fe (Fe0) and with Fe (Fe10-10 mu M Fe). Biomass parameters and root ferric chelate-reductase activity (FC-R; EC 1.16.1.17) were determined at the end of the experiment. Chlorophyll estimations (expressed as SPAD readings) decreased progressively, showing the typical symptoms of iron chlorosis. In addition, iron-deficient chia plants exhibit smaller biomass (number of leaves, root, and shoot growth reduction) compared to control plants. These plants also showed morphological changes in roots. Furthermore, root FC-R activity was significantly lower in Fe0 plants.
- Can bicarbonate enhance the performance of carob seedlings grown in nutrient solutions with different Fe concentrations?Publication . Gama, Florinda; Correia, Pedro José; Saavedra, T.; Dandlen, Susana; de Varennes, Amarilis; Nolasco, Gustavo; Pestana, MaribelaThe aim of this work was to assess the effect of bicarbonate (Bic) ion on the nutritional status and performance of carob-tree seedlings, a species that normally grows in calcareous soil without exhibiting iron chlorosis symptoms. Seedlings were previously grown in nutrient solution with a small concentration of Fe (0.5-1 mu M) to induce a moderate chlorosis. Afterwards, two experiments were established: in experiment 1, plants were grown for 21 days in the following treatments: Fe deficiency (Fe0), 0.5 mu M Fe, 5 mu M Fe, and 5 mu M Fe plus calcium carbonate (CaCO3). After assessing these results, a second experiment was conducted for 91 days, with the following treatments: Fe0, 1 mu M Fe, 40 mu M Fe and 40 mu M Fe plus CaCO3 and sodium bicarbonate (NaHCO3). Chlorophyll of young leaves, biomass and mineral composition of leaves, stems and roots were assessed in both experiments. The ferric chelate reductase root activity (FC-R) and the genetic expression of calmodulin-regulated Ca2+-ATPase pump (ACA gene) were evaluated in experiment 2. Fe-deficient plants exhibited reduced growth and enhanced macronutrients in leaves. Root micronutrient homeostasis changed as an adaptive mechanism in carob. The addition of bicarbonate did not aggravate Fe chlorosis, as leaf chlorophyll increased significantly. Root FC-R activity and ACA gene expression was not enhanced under Fe deficiency induced by bicarbonate (Fe40 + BicNa) which suggest a positive effect of bicarbonate in the metabolism of this crop. Nevertheless, small Fe concentrations (Fe1) induced a higher ACA gene expression thus indicating some stress response signalling.
- Carob: A mediterranean resource for the futurePublication . Martins-Loução, Maria Amélia; Correia, Pedro José; Romano, AnabelaFor centuries, the carob tree (Ceratonia siliqua L.) has contributed to the economy of the Mediterranean basin, mainly as food for livestock. Nowadays, the value of the carob tree extends far beyond its traditional uses, encompassing a wide range of industries and applications that take advantage of its unique properties and nutritional benefits. Despite its high industrial demand and European indications, there has been a 65% reduction in the area cultivated throughout the Mediterranean area in the 21st century. Given the threats posed by climate change, including reduced water availability and nutrient-depleted soils, there is a growing need to focus on this crop, which is well placed to cope with unpredictable weather. In this review, we use a bibliographic search approach to emphasise the prioritisation of research needs for effective carob tree exploitation. We found enormous gaps in the scientific knowledge of this under-utilised crop species with fruit pulp and seeds of high industrial value. Insufficient understanding of the biology of the species, as well as inadequate agronomic practices, compromise the quantity and the quality of fruits available to the industry. In addition to industrial applications, carob can also be used in reforestation or restoration programmes, providing a valuable crop while promoting biodiversity conservation and soil restoration. The carbon sequestration potential of the trees should be taken into account as a promising alternative in fighting climate change. This bibliographic search has highlighted clusters with different knowledge gaps that require further research and investment. The carob tree has untapped potential for innovation, economic development, and environmental sustainability.
- Changes in nutritional homeostasis of Poncirus trifoliata and Ceratonia siliquaas a response to different iron levels in nutrient solutionPublication . Correia, Pedro José; de Varennes, Amarilis; Gama, Florinda; Saavedra, Teresa; Pestana, MaribelaIron (Fe) deficiency is a nutritional disorder in plants. Poncirus trifoliata is susceptible to Fe deficiency, but symptoms of Fe deficiency are rare in Ceratonia siliqua, a slow-growing species. Specimens of the two species were grown in nutrient solutions containing three Fe concentrations: without Fe (0 mM), 1 mM Fe, and either 10 mM Fe (for Ceratonia) or 40 mM Fe (for P. trifoliata). Growth, the degree of chlorosis, the plant mineral composition, and the activity of the root ferric chelate-reductase (FCR) were assessed. Ceratonia plants exposed to 1 mM Fe were efficient at using Fe in the synthesis of chlorophyll. The activity of FCR was enhanced in the total absence of Fe. In Poncirus a low activity of the FCR was observed in plants with no Fe. The balance between micronutrients in the Ceratonia roots was not affected with 1 mM Fe compared with the higher Fe concentration treatments.
- Effects of foliar application of organic acids on strawberry plantsPublication . Saavedra, Teresa; Gama, Florinda; Rodrigues, Maria Joao; Abadía, Javier; de Varennes, Amarilis; Pestana, Maribela; Da Silva, José Paulo; Correia, Pedro JoséThe large economic costs and environmental impacts of iron-chelate treatments has led to the search for alter-native methods and compounds to control iron (Fe) deficiency chlorosis. Strawberry plants (Fragaria x ananassa) were grown in Hoagland's nutrient solution in a greenhouse with two levels of Fe: 0 and 10 mu M Fe(III)-EDDHA. After 20 days, plants growing without Fe showed typical symptoms of Fe deficiency chlorosis in young leaves. Then, the adaxial and abaxial sides of one mature or one young leaf in each plant were brushed with 10 mM malic (MA), citric (CA) or succinic (SA) acids. Eight applications were done over a two-week period. At the end of the experiment, the newly emerged (therefore untreated), young and mature leaves were sampled for nutritional and metabolomic analysis, to assess the effectiveness of treatments. Leaf regreening was monitored using a SPAD-502 apparatus, and the activity of the ferric chelate-reductase activity (FCR) was measured using root tips. Iron deficiency negatively affected biomass and leaf chlorophyll but did not increase FCR activity. Application of succinic acid alleviated the decrease in chlorophyll observed in other treatments, and the overall nutritional balance in the plant was also changed. The concentrations of two quinic acid derivatives increased under Fe deficiency and decreased in plants treated with succinic acid, and thus they are proposed as Fe stress markers. Data suggest that foliage treatments with carboxylates may be, in some cases, environmentally friendly alter-natives to Fe(III)-chelates. The importance of Fe mobilization pathways in the formulation of new fertilizers is also discussed.
- Enhancing growth, nutrient uptake and flowering of Tagetes patula plants through the application of suspensions of Chlorella vulgarisPublication . Vieira, João; Saque, Moisés; Viana, Catarina; Rodrigues, Maria Helena; Guerreiro David Coelho, Luísa Isabel; Gama, Florinda; Varela, João; Pereira, Hugo; Reis, Mário; Pestana, Maribela; Correia, Pedro JoséTagetes patula L. is a prominent plant that is frequently used for its ornamental value. Marigolds are sources of various compounds of great interest to agricultural, pharmaceutical, and nutritional industries. Microalgae can be applied as a biostimulant as they have multifunctional properties in agriculture, namely facilitating nutrient uptake, improving crop performance and physiological status, and thus increasing tolerance to abiotic stress. This study evaluated the efect of applying Chlorella vulgaris as a plant biostimulant on the growth and fowering of T. patula plants. Microalgae suspensions were applied to the substrate at concentrations of 0.5, 2.0 and 5.0 g dry weight (DW) L−1. A set of plants without the application of microalgae was used as control. The use of microalgae had a positive impact on plant growth. Specifcally, C. vulgaris application resulted in greater height, while the highest concentration (5.0 g DW L−1) resulted in higher fresh weight. Microalgae application signifcantly promoted the earlier fowering of marigolds. The macronutrient and micronutrient values were statistically similar between the control plants and those treated with microalgae. When considering only the treated plants, there was a signifcant correlation between the concentration of C. vulgaris and the concentrations of N, P, Mn and Cu in the shoots of T. patula plants. Plants receiving higher concentrations of C. vulgaris exhibited higher levels of these nutrients. These results highlight the potential use of Chlorella vulgaris as an efective biostimulant for enhancing the growth, fowering, and nutrient uptake of T. patula, ofering valuable applications for improving ornamental plant production and, ultimately, agricultural sustainability.
- Evaluation of carob tree productivity during a 30-year period, in relation to precipitation and air temperaturePublication . Correia, Pedro José; Cota, Tania; Pestana, MaribelaWater availability for irrigation of intensive crops will become a major problem in southern Iberia. One of the tools to sustain land use under water shortage is to choose crops well adapted to those environmental stress conditions featuring low water demand. The aim of this paper is to explore several relationships between climatic variables and the fruit production of carob-tree (yield) in a series of 30 consecutive years (1985-2015) referred to one single orchard. Precipitation and air temperature were the selected variables and regression models were tested. It was not possible to find any relations between yield and temperature, but precipitation during the hydrological year was inversely and significantly related to yield (Model 1- R-2 = 0.18). A close analysis indicated that rainfall registered during autumn was particularly effective, since higher yields were obtained in the years with less rainfall registered in the period September + October + November (SON) (Model 2; R-2 = 0.21). Although the air temperature effect was not found significant, mean values between 22.0 and 24.5 degrees C during SON were crucial to flowering and yield. Model 2 was validated using an independent data set considering 3 years, and the calculated yields were overestimated by 18.6% and 4.0% in two consecutive seasons. Moreover, Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios predict a precipitation decrease for SON period in the region, which may create favorable conditions for insect pollination and fruiting success.
- Evaluation of Chlorella vulgaris application as a biostimulant for lettuce growth in soilless culturePublication . Vieira, João; Saque, Moisés; Gama, Florinda; Viana, Catarina; Guerreiro David Coelho, Luísa Isabel; Rodrigues, Maria Helena; Varela, João; Pereira, Hugo; Palencia, Pedro; Reis, Mário; Pestana, Maribela; Correia, Pedro JoséThis study evaluated the effect of Chlorella vulgaris application on the growth of soilless-grown lettuce (Lactuca sativa cv. 'Oreja de Mulo') cultivated outdoors. Microalgae suspensions were applied weekly at concentrations of 0.5, 2.0, and 5.0 g L(-)1. Plants grown without the application of microalgae were used as the control. Leaf chlorophyll concentration was registered at the beginning and at the end of the experiment, and biomass parameters were assessed at harvest. Compared with control, the highest concentration of C. vulgaris (CV5) exhibited the maximum increase in leaf area (67.4%), root fresh weight (138.7%), root volume (92.1%) and root dry weight (150.0%). This concentration further promoted higher accumulation of nitrogen (44.9%), phosphorus (96.4%), potassium (59.5%), and iron (Fe) (43.8%) in aerial parts of the lettuce plants These findings demonstrate the potential of C. vulgaris suspensions as effective biostimulants for improving growth, nutrient uptake, and biomass accumulation in hydroponic lettuce production, supporting more sustainable agricultural practices.
- Exploratory analysis of the productivity of carob tree (Ceratonia siliqua) orchards conducted under dry-farming conditionsPublication . Correia, Pedro José; Pestana, MaribelaIn Southern Portugal (Algarve), the occurrence of extreme climatic events has become more limiting to agriculture and forestry productivity. Severe or moderate drought during spring, summer, and autumn is common, with major implications on yield, farmers income, and on a long-term basis, land use. Facing this scenario, farmers rely on certain crops in order to obtain a complementary revenue, as an alternative to more intensive and high-demanding farming. One of these crops is carob tree, a multipurpose and industrial fruit tree species very well adapted to dry-farming conditions and very important to the sustainability of these fragile agroecosystems. The aim of this study is to analyse the fruit productivity during 30 years in two mature carob tree orchards grown in two contrasting soils: a fertile, calcareous soil and in a non-fertile soil. Based on this exploratory analysis, the gross income of farmers obtained from fruit selling in the regional market is discussed. Moreover, the possibility of using tree carbon sequestration as an ecosystem service shall be considered as a novel alternative in these depreciated agroecosystems.
- Fruit quality response of strawberry cv 'antilla' after application of calciumPublication . Palencia, Pedro; Pestana, Maribela; Saavedra, Teresa; Gama, Florinda; Correia, Pedro JoséAs an important economically and nutritionally valuable fruit, strawberry has been planted everywhere worldwide, which, due to the shortage of arable land, has created an obstacle to successional farming. The study investigates the effect of calcium application in strawberry fruit quality, including fruit firmness and ºBrix. Strawberries (Fragaria × ananassa Duch. 'Antilla') grown in a soilless system in a greenhouse were exposed to different calcium (Ca) concentrations and application interval during the production cycle of strawberry plants added as Ca(NO3)2. The control only has the Ca contained in the irrigation water. The S treatment added Ca to the substrate, FS and FQ treatments added Ca by foliar spray weekly or biweekly, respectively. Fruit fresh weight, firmness, pH, titratable acidity and ºBrix value were studied. Compared to other treatments, softer fruits were obtained in the control group. The reduction of fruit firmness in the control treatment coincides with a lower average pH, which can cause fruit softening and damage during storage. In addition, pH plays an important role in strawberry flavour. Foliar application of Ca showed strawberries with higher firmness, irrespective of the application interval weekly or biweekly. From an environmental standpoint, optimizing calcium application in soilless systems contributes to resource-efficient agriculture by reducing nutrient waste, minimizing leaching, and lowering the environmental footprint associated with excessive fertilizer use. This approach supports sustainable fruit production, especially in areas facing soil degradation and water scarcity, thereby aligning strawberry cultivation practices with broader environmental conservation goals.
- «
- 1 (current)
- 2
- 3
- »