Browsing by Author "Correia, P. J."
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- Combined effects of potassium and wastewater application on the yield and quality of Bermuda grass (Cynodon dactylon) in the Mediterranean regionsPublication . Beltrão, José; Santos, R.; Correia, P. J.The reuse of treated wastewater is considered as an alternative disposable to potable water in the mediterranean agriculture and landscape, namely in golf courses. Bermuda grass (Cynodon dactylon, Peers) is used very often on the fairways, roughs and tees of golf courses of the Mediterranean Basin due to its tolerance to drought, salinity, high temperatures and damages. The objective of this work is to study the response of this cultivar to the combined effects of municipal wastewater and two levels of potassium fertilization, during Spring and Summer. The experimental design known as sprinkle point source was used to simulate the various levels of wastewater application, expressed by the crop coefficient kc. This procedure is characterized by the assumption that a point creates a linear irrigation gradient from the water point source, producing a gradual change in water application, and a high degree of irrigation uniformity must be obtained in parallel isohyets. Chemical analysis of wastewater irrigation water was monitored through all the experimental period (from April to September). Climatic data was also recorded. Yield (aboveground biomass) and the good visual appearance (GVA) of the lawn were assessed in two sampling dates, May and July. Municipal wastewater can be used to irrigate Bermuda grass, without an apparent decrease on grass quality. As concluding remarks, it may be seen that the irrigation water amount is the most pronounced limiting production factor of bermuda grass (Cynodon dactilon, Peers), when compared with potassium fertilization, but it is possible that there is a positive interaction between water and irrigation. This response is modulated by evaporative air conditions since lower yields were obtained in summer. On the other hand, if the potassium fertilization is increased, two situations may occur: 1) with high amounts of water application, leaching problems may occur, mainly on sandy soils, and production may decrease; 2) if potassium fertilization increases, and irrigation water decreases, yield decreases due to the increase of salinity (potassium fertilizers are salts), mainly on salt affected soils.
- Consequences of iron deficiency on fruit quality in citrus and stawberryPublication . Pestana, M.; Varennes, Amarilis de; Miguel, Maria Graça; Correia, P. J.; Nunes, CarlaIron deficiency (iron chlorosis) is an important nutritional disorder in several plants, including fruit trees and strawberry. Iron chlorosis does not result from a small level of iron in soils but rather from impaired acquisition and use of this metal by plants. Calcium carbonate, present in great amounts in calcareous soils, and the resulting large levels of bicarbonate ions, are the main causes of iron deficiency. Countries in southern Europe, such as Portugal, Spain, Italy and Greece, have large areas of calcareous soils with established orchards, where iron chlorosis is a major factor that limits yield and profit for the farmer. Iron chlorosis affects several metabolic processes and leads to nutrient imbalances in sensitive plants. Decreased yield and poor quality of fruit resulting from the iron deficiency justify the development of methods to diagnose and correct this disorder. No single approach has been found to solve iron chlorosis satisfactorily, making it one of the most complex nutritional deficiencies known. In this chapter we describe some aspects of the effects of iron availability on quality of strawberry and citrus fruit.
- Determination of chemical composition of Anatolian carob pod (Ceratonia siliqua L.): sugars, amino and organic acids, minerals and phenolic compoundsPublication . Ayaz, Faik Ahmet; Torun, Hülya; Ayaz, Sema; Correia, P. J.; Alaiz, Manuel; Sanz, Carlos; Grúz, Jiri; Strnad, MiroslavCarob pod is the fruit of the carob tree (Ceratonia siliqua L. Fabaceae). The fruit and its products, sold both in large stores and local markets, contribute strongly to the diet of people living in the Mediterranean areas of Europe and Turkey. This study reports the composition of carob pods sampled in West and South Anatolia. Sucrose (437.3 mg/g dry weight), glucose (395.8 mg/g dry weight) and fructose (42.3 mg/g dry weight) were the major sugars identified and quantified in the fruit. Total phenolics (13.51 mg gallic acid equivalents [GAE]/g dry weight), proanthocyanidin (0.36 mg GAE/g dry weight), gallotannins (0.41 catechin equivalents [CE]/g dry weight) and flavanols (3.21 mg CE/g dry weight protein) content of the fruit were also determined. Gallic acid (3.27 mg/g dry weight) was the most abundant phenolic acid present in all three phenolic fractions (free, ester and glycoside) isolated from pods. Aspartic acid (18.25 mg/g dry weight protein) was the predominant amino acid in the pod protein fraction. Eight minerals were quantified in the fruit. Among the analyzed major minerals, K (9.70 mg/g dry weight) was the most abundant element present, and the pods were richer in Ca than in P and Mg. Levels of trace minerals were comparable to other plant species. The data are discussed in terms of the nutritional value of the carob pod.
- Development and recovery of iron deficiency by iron resupply to roots or leaves of strawberry plantsPublication . Pestana, M.; Correia, P. J.; Saavedra, Teresa; Gama, Florinda; Abadía, Anunciación; Varennes, Amarilis deBare-root transplants of strawberry (Fragaria ananassa Duch. cv. ‘Selva’) were transferred to nutrient solutions with or without iron (Fe). After six weeks of growth, plants grown in solution lacking Fe were chlorotic and showed morphological changes in roots typical of Fe deficiency. Subsequently, four treatments were applied for nine days: plants grown in continued absence of Fe (Fe0); plants grown in continued presence of 10 mM Fe (Fe10); foliar application of ferrous sulphate every two days to chlorotic plants (Fe-leaves); and growth of chlorotic plants in solution with ferrous sulphate (Fe-solution). After six days, the chlorophyll (Chl) content in leaves of Fe-solution plants was similar to that in Fe10 plants. Under the Fe-leaves treatment, a slight regreening of new leaves was observed only by the end of the experiment. After nine days, ferric chelate reductase (FC-R) activity was unchanged in Fe10 but increased in Fe0 plants. The FC-R activity of Fe-solution plants was similar to the initial value for chlorotic plants, whereas it was reduced drastically under the Fe-leaves treatment. The Fe concentration in leaves of Fe0 and Fe10 was similar, whereas the Fe-solution and Fe-leaves treatments enhanced leaf Fe concentration. In contrast to the Fe-solution treatment, foliar application of Fe did not increase the Fe concentration in roots. Under our experimental conditions, FC-R activity in strawberry appeared to be deactivated rapidly by pulses of Fe applied by foliar sprays. Deactivation was slower if Fe was applied directly to roots, which suggested that the plants had greater opportunity to take Fe.
- Effect of N-nutrition and irrigation on carob (Ceratonia siliqua L.) fruit productionPublication . Correia, P. J.; Martins-Loução, M. A.Carob is a traditional crop in Mediterranean areas. It exhibits drought resistance (Lo Gullo and Salleo 1988. Nunes et al. 1989) and tolerates different edaphic conditions (Martins-Loução and Brito de Carvalho 1990).
- Effect of nitrogen and potassium fertilisation on vegetative growth and flowering of mature carob trees (Ceratonia siliqua): variations in leaf area index and water use indicesPublication . Correia, P. J.; Martins-Loução, M. A.This work aimed to assess how potassium (K) and nitrogen (N) fertilisation may affect the use of precipitation in terms of vegetative and flowering response of 15-year-old carob trees during a 3-year experiment. A field trial was conducted in 1997, 1998 and 1999 in Algarve (Southern Portugal) in a calcareous soil. Four fertilisation treatments were tested: no fertiliser (control); 0.8 kg N/tree (N treatment); 1 kg K 2 O/tree (K treatment) and 0.8 kg N/tree plus 1 kg K 2 O/tree (NK treatment). No irrigation was applied during the experimental period. Branch length increments were measured every month throughout the growing season and inflorescence number was registered once per year. There was a strong seasonal effect on vegetative growth, since low levels of precipitation (115 mm) during October 1998–March 1999 suppressed the increment in branch length. N supplied to the trees (N and NK treatments) tended to increase water use indices in terms of vegetative growth. No response to K alone was observed in trees fertilised only with K. The number of inflorescences increased throughout the experimental period, particularly for N and NK treatments, and a reduction of the precipitation amount during April, May and June, may also enhance flowering. This knowledge could be important when making decisions concerning fertilisation under dry conditions. The results reported here indicate that tree growth (expressed as the branch growth) and flower production under dry-farming conditions, may be achieved by applying 0.8 kg of N (as ammonium nitrate) per tree during the growing season. However, N uptake and use depends on soil water availability.
- Effectiveness of different foliar iron applications to control iron chlorosis in orange trees grown on a calcareous soilPublication . Pestana, M.; Correia, P. J.; Varennes, Amarilis de; Abadía, Javier; Faria, E. A.The effectiveness on controlling Fe chlorosis in orange trees grown on calcareous soils was tested. The treatments were Fe(II) sulfate (500 mg Fe L ÿ1), sulfuric acid (0.5mM H2SO4), Fe(III)-chelate (Hampiron 654 GS, 120 mg Fe L ÿ1) and distilled water as a control. A non-ionic wetting agent was used in all treatments. The use of frequent foliar sprays alleviated Fe chlorosis in orange trees. Sprays of Fe(II) sulfate increased the concentrations of chlorophyll, Fe and zinc in leaves and improved fruit size and quality compared to fruits of control trees. Sprays of Fe(III)-chelate also increased leaf chlorophyll and Fe concentrations and improved fruit quality, but did not increase fruit size. Sprays of sulfuric acid alone slightly increased leaf chlorophyll and Fe concentrations, without improving fruit size and quality. These results suggest that foliar sprays with Fe could help to avoid yield and quality losses caused by Fe chlorosis in citrus orchards. Furthermore, these treatments could be done with relatively cheap materials such as solutions containing Fe(II) sulfate.
- Effects of fertiliser practices on the growth and quality of two table grape cultivars: 'Cardinal' and 'D. Maria'.Publication . Domingos, I.; Silva, T.; Correia, P. J.; Correia, Maribela Pestana; de Varennes, A.In this study, the different fertilliser practices of four commercial vineyards (Vitis vinifera L. cv. 'Cardinal' and cv. 'D. Maria') in southern Portugal were assessed and compared in 2002. The vineyards were established in similar soils under the same climatic conditions and additional water was supplied by drip irrigation. At harvest, the mineral composition of petioles (P, K, Mg, Ca, Fe, Cu, Zn and Mn) and quality parameters of the grapes (total soluble solids expressed as degree Brix, cluster length and weight, number of grapes, grapes weight and rachis weight) were recorded. For the 'Cardinal' cultivar, the nutritional status of the plant was correlated with growth and yield, and the greatest values for most of the parameters studied were measured at Alvisquer farm. For the 'D. Maria' cultivar, a single correlation was found between nutrient levels and growth. Shoot and cluster lengths, and grape weight were similar at all farms, though cluster weight, number of grapes and total soluble solids were smaller at Pedras than at Alvisquer or Gomeira.
- Fe deficiency induction in Poncirus trifoliata rootstock growing in nutrient solution changes its performance after transplant to soilPublication . Gama, Florinda; Saavedra, Teresa; Diaz, I.; del Carmen Campillo, M. D.; de Varennes, A.; Duarte, Amílcar; Pestana, M.; Correia, P. J.The absence of iron (Fe) in the nutrient solution induces several physiological and morphological adaptations in the roots of Poncirus trifoliata, a citrus rootstock, thereby modifying its overall nutritional status. Whether these changes are advantageous when plants are transplanted to calcareous soils needs to be assessed. To achieve this objective a two-phase experiment was established, first in nutrient solution (phase I) then in pots containing different soils (phase II). In phase I, P. trifoliata L. Raf. plants were grown in Hoagland’s solution with 120 M of Fe (Fe120 treatment) or without (Fe0 treatment). At the end of phase I (87 days), Fe-chlorotic plants had less chlorophyll in apical younger leaves, root tips were swollen and their FC-R activity was enhanced, typical responses to Fe-stress. Chlorotic plants had less Fe compared to control plants, but accumulated more Cu and Zn. In contrast the root to shoot ratio (dry weight) and the amounts of macronutrients were not affected by Fe chlorosis. In phase II, plants of both treatments were transplanted to pots containing a calcareous (C) or a non-calcareous (nC) soil resulting in four treatments: Fe0nC, Fe120nC, Fe0C and Fe120C. From the end of phase I until the end of the experiment (353 days), the calcareous soil negatively affected the overall nutritional balance in both Fe0 and Fe120 treatments. Apparently, the ability to change metal homeostasis in particular Cu, as a Fe-stress response was maintained in plants grown in non-calcareous soil. Moreover, the previous induction of physiological and morphological adaptations to Fe depletion alleviated the iron chlorosis symptoms caused by soil carbonates. These results may point to the utilization of internal stress signalling as a tool to cope with different soil conditions.
- Floral analysis and seasonal dynamics of mineral levels in carob tree leavesPublication . Custódio, Luísa; Correia, P. J.; Martins-Loução, M. A.; Romano, AnabelaThe mineral concentration of flowers and the seasonal fluctuation of macro- [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] and micronutrients [iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu)] in leaves of male, female, and hermaphroditic carob trees (Ceratonia siliqua L.) were studied. The nutrient dynamics were linked not only to phenological events, but also to the gender of the trees. The females were able to allocate more nutrients to leaves than male trees, even though male flowers were richer in particular elements such as N and Zn. The hermaphrodites supported the development of both inflorescences and fruits with a lower seasonal variation and a lower leaf nutrient concentration, as compared to the other genders, which may indicate a more efficient use of resources. Flowers had, in general, a higher concentration of N, P, and K, and a lower Mn concentration than in leaves. Flowers of the females had a lower nutrient concentration compared to males or hermaphrodites.
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