J. Ferreira-Cardoso

Histopathological changes in liver and gill epithelium of Nile tilapia, Oreochromis niloticus, exposed to waterborne copper

Nile tilapia, Oreochromis niloticus, of both sexes were reared in freshwater and exposed to 0.5, 1.0 and 2.5mg L-1 of waterborne copper for a period of 21 days. Liver and gill samples were collected after 21 days of exposure to copper and lesions were analyzed by light microscopy. The main histopathological changes observed in gills exposed to the highest concentration were edema, lifting of lamellar epithelia and an intense vasodilatation of the lamellar vascular axis. Although less frequent, lamellar fusion caused by the filamentar epithelium proliferation and some lamellar aneurisms were also found. The liver of control group exhibited a quite normal architecture, while the fish exposed to copper showed vacuolation and necrosis. These hepatic alterations were more evident in fish exposed to 1.0 and 2.5mg L-1 copper concentrations. The number of hepatocytes nucleus per mm2 of hepatic tissue decreased with the increase of copper concentration. In contrast, the hepatic somatic index was high in fish exposed at 2.5mg L-1 of copper. In short, this work advance new knowledge as influence of copper in the gill and liver histology of O. niloticus and demonstrated that their effects could be observed at different concentrations.

BORON APPLICATION ON A CHESTNUT ORCHARD: EFFECT ON YIELD AND QUALITY OF NUTS

Although boron (B) deficiency in chestnuts (Castanea sativa Mill.) has been identified in Portugal and B fertilization was carried out in some orchards, the post-treatment evaluations have not been made to date. So the objective of this trial was to confirm the B deficiency and to quantify the effect of B applications to the soil on nut yield and quality. In October 2006, a fertilizer trial was established in a 15 year-old orchard in a very acid soil derived from siliceous schists. Soil liming and a basal fertilization were carried out in 16 trees and two levels of sodium tetraborate (Granubor, 14.6% B) were applied to eight trees: control (B0) and 100 g of Granubor per tree (B1). In the beginning of September chestnut leaves were collected from five trees and analyzed for macro- and micronutrients. Nut productivity was measured per tree and some nut quality parameters were evaluated, including the chemical composition of the kernel (soluble sugars, starch, total fiber, crude protein, and crude fat) in 2007, and dry matter, nut caliber, and fruit damage in 2007 and 2008. Boron fertilization of chestnuts significantly increased nut production: 75% in the first year (8 kg and 14 kg per tree, respectively, in the B0 and B1) and, in the second year, was over four times higher (4 kg and 17 kg per tree, respectively, in the B0 and B1). No significant differences were found in dry matter, nut caliber, nut damage and chemical composition of the kernel in the first year, but in the second year lower fruit damage by chestnut tortrix (P<0.0089) was observed. Foliar analyses exhibit relatively low B concentrations in the control trees (average value of 8 mg kg−1) in both years, while in the fertilized trees the foliar B concentration were in average 61 mg kg−1 in the first year, and 34 mg kg−1 in the second year. The large drop in the foliar B concentration in the second year suggests the need to monitoring the nutrient status of chestnut orchards or more frequent of B application than usual practice.

Study of morphological and chemical diversity in chestnut trees (var. “Judia”) as a function of temperature sum Estudio de la diversidad morfológica y química del fruto de castaña (var. “Judia”) en función de la suma de la temperatura

Fruits of variety “Judia” (Castanea sativa Mill.) were collected in different climatic locations during 2006 and 2007 and the average of sum temperature (degree-days, °D) were 2457 °D and 2147 °D (May–October), respectively. In 2007, the fruits were 38% bigger and contained 50% more starch than those from 2006 but they had less 6.41% crude fat content. In 2006, nuts from the coldest place (Valpaços: 1895 °D) were the biggest (62.5 fruits/kg) and had the highest content in starch (400.7 g/kg DM) contrarily to the fruits from the hottest place (Murça: 2751°D), which were the smallest (157.1 fruits/kg). In 2007, the biggest fruits were yielded in Macedo Cavaleiros (2163 °D) 46.4 fruits/kg, repeating Murça with smallest fruits (66.0 fruits/kg). The Nei genetic distances between trees ranged between 0.0 and 0.227 proving that all of them are from the same variety. Los frutos de la variedad “Judía” (Castanea sativa Mill.) fueron recolectados en diferentes zonas climáticas, durante 2006 y 2007, con un promedio sumatorio de temperatura (días-grado, °D) de 2457 y 2147 °D (mayo-octubre), respectivamente. En 2007, los frutos fueron un 38% más desarrollados, conteniendo un 50% más de almidón que los de 2006, y un 6,41% de menos de grasa cruda. En 2006, los frutos del lugar más frío (Valpaços: 1895 °D), fueron los que registraron mayores tamaños (62,5 frutos/kg) y contenidos más altos de almidón (400,7 g/kg peso seco). Resultados contrarios a éstos fueron los obtenidos para los frutos de la localidad más cálida (Murça: 2751 °D), que fueron los que registraron tamaños más pequeños (157,14 frutos/kg). En 2007, los mayores frutos procedieron de Macedo Cavaleiros (2163 °D), 46,4 frutos/kg, siendo de nuevo Murça (2338 °D) la que proporcionó los frutos más pequeños (66,0 frutos/kg). Las distancias genéticas de Nei entre los árboles oscilaron entre 0,0 y 0227, demostrando que todos ellos son de la misma variedad.

Differences in photosynthetic apparatus of leaves from different sides of the chestnut canopy

In crowns of chestnut trees the absorption of radiant energy is not homogeneous; leaves from the south (S) side are the most irradiated, but leaves from the east (E) and west (W) sides receive around 70 % and those from north (N) face less than 20 % of the S irradiation. Compared to the S leaves, those from the N side were 10 % smaller, their stomata density was 14 % smaller, and their laminae were 21 % thinner. N leaves had 0.63 g(Chl) m−2, corresponding to 93 % of total chlorophyll (Chl) amount in leaves of S side. The ratios of Chl a/b were 2.9 and 3.1 and of Chl/carotenoids (Car) 5.2 and 4.8, respectively, in N and S leaves. Net photosynthetic rate (PN) was 3.9 µmol(CO2) m−2 s−1 in S leaves, in the E, W, and N leaves 81, 77, and 38 % of that value, respectively. Morning time (10:00 h) was the period of highest PN in the whole crown, followed by 13:00 h (85 % of S) and 16:00 h with 59 %. Below 500 µmol m−2 s−1 of photosynthetic photon flux density (PPFD), N leaves produced the highest PN, while at higher PPFD, the S leaves were most active. In addition, the fruits from S side were 10 % larger than those from the N side.

Structural analysis of Castanea sativa Mill. leaves from different regions in the tree top

The aim of this work was to perform the histological characterization of the C. sativa leaves of three Portuguese cultivars to establish comparison among the leaves of the different quadrants in accord and with the cardinal points of the tree top and among different cultivars of this species, using light microscopy (OM) and scanning electron microscopy (SEM). Measurements were also carried out for the leaf tissue thickness, stomatal density, leaf area in the four tree top quadrants. The leaves turned to the North had lesser thickness of mesophyll mainly due to lower amount of palisade parenchyma. The stomatal density was significantly lower in these leaves, unlike the leaf area that has the highest expression.

Assessment of Boron Application in Chestnuts: Nut Yield and Quality

A field trial was conducted between 2006 and 2009 in order to quantify the effect of boron (B) application on the yield and quality of chestnuts. The trial was established in an acid soil derived from siliceous schist and two levels of B were applied. Fruit abortion and nut yield per tree were measured, and nut quality parameters and chemical composition of the kernel were determined. Foliar B concentration was 8.6 mg kg−1 in the control trees and 48.4 mg kg−1 in fertilized chestnuts. Boron improved fruit setting and promoted nut production by 77%. In 2008, the occurrence of cold temperatures enhanced the effect of B on fruit setting, which was four-fold, whereas with the normal temperatures of 2009 the increase was lower. The drought of 2009 was responsible for the ruinous chestnut caliber and shell cracking. Boron induced a significant increase in the crude fat of chestnut kernel.

Influence of the growing degree-days on chemical and technological properties of chestnut fruits (var. "Judia")

The influence of different edaphoclimatic conditions in “Judia” variety from seven different localities in the Trás-os-Montes region was evaluated with respect to metabolites, fatty acids, and technological properties. Significant correlations between edaphoclimatic conditions and moisture content, crude protein and especially fatty acids were investigated. Alfândega da Fé, with 2032 °D (degree-day), has the best corrected caliber and the lowest percentage of depth kernel wrinkles. However, the coldest localities (1597 °D and 1971 °D) had the highest moisture, crude protein, soluble sugars, and starch content and a clear prevalence of polyunsaturated fatty acids. The moisture loss of the chestnut fruits was also different among localities, which could lead to a different economic value. This study is important because it supplies the knowledge that trees from the same variety can produce different quality fruits depending on their origin of growth and the influence of different edaphoclimatic conditions.