Water-related ecological impacts of rill erosion processes in Mediterranean-dry reclaimed slopes

Soil moisture is considered the main limiting factor governing the structure and dynamics of vegetation in drylands. Soil erosion is perceived as a critical process affecting these systems, especially when rill formation occurs, as rill networks can condition the availability and spatial distribution of soil moisture. To assess the impact of soil erosion processes on the dynamics of Mediterranean-dry reclaimed systems, during the 2005–06 hydrological year we monitored the soil moisture regime (temporal availability and spatial distribution) and the associated responses describing vegetation performance (plant water status and potential seed germination) and vegetation structure in five coal-mining reclaimed slopes subjected to different rill erosion rates (from 0 to about 70 t ha^? 1 year^? 1). Rill network development leads to increased runoff connectivity and to concentration of water flow along the channeling network. As a result, water loss from the slope system is maximized. Simultaneously, the spatial distribution of soil moisture is ruled by the pattern of geomorphic forms (rill and interrill units). The ecological consequences are led by the intensification of water stress and the occurrence of unfavorable conditions for plant recruitment and natural colonization, causing a non-linear decline of species richness and aboveground biomass at the slope scale level. When dense rill networks are developed, long-term effects of erosion result in a sharp ecosystem transition to a very simple and low productive plant community spatially organized in downward spots adjacent to the rills, where plants minimize simultaneously water stress and the mechanical disturbance associated to concentrated flows.     

Postharvest treatments with salicylic acid, acetylsalicylic acid or oxalic acid delayed ripening and enhanced bioactive compounds and antioxidant capacity in sweet cherry

Sweet cherry cultivars ('Cristalina' and 'Prime Giant') harvested at commercial ripening stage were treated with salicylic acid (SA), acetylsalicylic acid (ASA) or oxalic acid (OA) at 1 mM and then stored for 20 days under cold temperature. Results showed that all treatments delayed the postharvest ripening process, manifested by lower acidity, color changes and firmness losses, and maintained quality attributes for longer periods than controls. In addition, total phenolics, anthocyanins and antioxidant activity increased in untreated fruit during the first 10 days of storage and then decreased, while in fruits of all treatments, these parameters increased continuously during storage without significant differences among treatments. Thus, postharvest treatments with natural compounds, such as SA, ASA or OA, could be innovative tools to extend the storability of sweet cherry with higher content of bioactive compounds and antioxidant activity as compared with control fruits.     

Characteristic phenolic composition of single-cultivar red wines of the Canary Islands (Spain)

The detailed phenolic composition of five single-cultivar (Baboso Negro, Listán Negro, Negramoll, Tintilla, and Vijariego Negro) young and aged (vintages 2005-2009) red wines of the Canary Islands has been determined by HPLC-DAD-ESI-MS(n). Despite the total monomeric anthocyanin content decreasing for older wines in each set of single-cultivar wines, the corresponding anthocyanin profiles remained almost unchanged. Although all wine anthocyanin profiles were dominated by malvidin 3-glucoside, their differentiation by grape cultivar was possible, with the exception of Listán Negro. In contrast, the total content of non-anthocyanin phenolics did not appreciably change within vintages but polymerization, hydrolysis, and isomerization reactions greatly modified the phenolic profiles. Aglycone-type flavonol profiles offered the best results for differentiation of the wines according to grape cultivar (Listán Negro and Negramoll; Baboso Negro and Vijariego Negro; and Tintilla). Within flavan-3-ols, the B-ring trihydroxylated monomers ((-)-epigallocatechin and (-)-gallocatechin) and also (-)-epicatechin provided additional cultivar differentiation. Hydroxycinnamic acid derivatives and stilbene profiles were very heterogeneous with regard to both grape cultivar and vintage and did not significantly contribute to wine differentiation, even when structure-type profiles were obtained, with the exception of Tintilla, which always appeared as the most different single-cultivar wines. Finally, most Canary Islands wines showed characteristic high contents of stilbenes, especially trans-resveratrol.     

Gastroprotective and ulcer-healing mechanisms of ellagic acid in experimental rats

Ellagic acid (EA), a plant-derived polyphenol, exhibits antioxidant, anti-inflammatory, and gastroprotective effects. Its gastroprotective mechanisms have not been fully elucidated nor have its effects on chronic ulcer previously been described. Toward these ends, the antiulcer activities of EA were evaluated in acute (ethanol and indomethacin) and chronic (acetic acid) ulcer models in Wistar rats. In this study, oral administration of EA significantly prevented the gastric ulceration caused by ethanol, indomethacin, and acetic acid treatments. Its gastroprotective mechanism in ethanol-induced ulcer were partly due to intensification in the endogenous production of nitric oxide, an antioxidant effect by replenishing depletion of endogenous nonprotein sulfhydryls and attenuation of tumor necrosis factor-α increase, whereas in indomethacin ulcer, it is partly due to a reduction in the plasma level of leukotriene B(4). In acetic acid ulcer, promotion of ulcer-healing effects was partly due to attenuation of the elevated levels of the inflammatory cytokines TNF-α, interferon-γ, and interleukins-4 and -6. These findings suggest that ellagic acid exerts its antiulcer activity by strengthening the defensive factors and attenuating the offensive factors.     

Tetrahydrofolic Acid is a potent suicide substrate of mushroom tyrosinase

The coenzyme tetrahydrofolic acid is the most rapid suicide substrate of tyrosinase that has been characterized to date. A kinetic study of the suicide inactivation process provides the kinetic constants that characterize it: λ(max), the maximum apparent inactivation constant; r, the partition ratio or the number of turnovers made by one enzyme molecule before inactivation; and k(cat) and K(m), the catalytic and Michaelis constants, respectively. From these values, it is possible to establish the ratio λ(max)/K(m), which represents the potency of the inactivation process. Besides acting as a suicide substrate of tyrosinase, tetrahydrofolic acid reduces o-quinones generated by the enzyme in its action on substrates, such as l-tyrosine and l-DOPA (o-dopaquinone), thus inhibiting enzymatic browning.     

Repeatability of full-sib sugarcane families across harvests and the efficiency of early selection

This study was designed to estimate the repeatability coefficient of traits of the plant-cane and first rattoon in a large number of full-sib sugarcane families and to select the superior families based on their predicted genotypic values. The population used in this study consisted of 190 families, and crossing was performed at the Federal University of Alagoas, in Murici, Alagoas, Brazil, in 2007. Five experiments, each with 22 families, took place at the Centro de Pesquisa e Melhoramento da Cana-de-Açúcar (CECA), in Oratórios, Minas Gerais, while four experiments, each with 20 families, took place at the Volta Grande mill (VGM), in Conceição das Alagoas, Minas Gerais. Each experiment took the form of a randomized complete block design with six replications. The following traits were determined from the plant-cane and first rattoon: percentage of soluble solids w/w in the juice (Brix), tons of stalks per hectare (TSH) and tons of brix per hectare (TBH). Statistical analyses were performed using the mixed model methodology. Variance components were estimated by restricted maximum likelihood (REML) and the genotypic values of families were predicted by best linear unbiased prediction (BLUP). The moderately high estimates of repeatability for TSH and TBH and the high rates of coincidences of the families selected in both plant-cane and first rattoon indicate that selection of families using repeated measures across the first two harvests combined with individual clone selection at the rattoon stage may be efficient in sugarcane breeding programs, increasing the efficiency of obtaining new cultivars.     

Prediction of stand quality characteristics in sweet chestnut forests in NW Spain by combining terrain attributes, spectral textural features and landscape metrics

Chestnut woods are outstanding elements of European cultural landscapes, and are also recognised as habitats of interest in the Natura 2000 European network of protected areas. Despite their importance, they are threatened by land abandonment and recent rural landscape changes. The loss of Castanea sativa cover and its dominance as a characteristic species may indicate forest degradation, which can occur as a result of natural succession dynamics or invasion by alien species.In this study we aimed to model the conservation status of chestnut stands in the NW Iberian peninsula in terms of their environmental and cultural value, formulated as a quality index that considers the maturity and purity of forest stands. We used features available at wide geographic scales as potential predictors, namely topographic parameters derived from Digital Elevation Models, land-cover heterogeneity determined by means of satellite image texture and landscape metrics. According to the results, altitude emerged as a major factor determining chestnut stand quality, marking a clear difference between highland and lowland environments. The combination of terrain, texture and patch shape refined the classification of each of these scenarios. We discuss the significance of these predictors as environmental controls and indicators of anthropogenic effects.     

Influence of geographical location, site and silvicultural parameters, on volatile composition of Quercus pyrenaica Willd. wood used in wine aging

For the current study, the volatile and semi-volatile composition of several samples of Quercus pyrenaica wood from NW Spain were analyzed and compared. The research was performed on a wide sample set of more than 100 samples (test tubes) obtained from different stands of this species. The relationship between some silvicultural and site parameters and volatile composition was studied. Altitude seemed to be the most influential parameter on the volatile composition. However, other factors such as distance from tree center, average annual precipitation, and number of trees per hectare whose effects on the volatile compounds were not significant. The influence of soil texture was not a determining factor while geographical location seemed to have a more specific impact on the extractive volatile content. The content of all extractable compounds studied allowed a good separation of oak samples of the same species according to their geographical origin.     

Kinetic study of the physicochemical and microbiological changes in "seasoned" olives during the shelf-life period

The changes that take place during the shelf life of "seasoned" olives (packing conditions: 4% NaCl, 0.1%citric acid, and 0.0175% sorbate) using fresh (FF) and stored (SF) cracked fruits were studied. Texture, L, b, NaCl, and pH experienced slight changes. Values of a and titratable and combined acidity increased following a first-order kinetic with higher constants for FF. Glucose was completely exhausted, and mannitol showed only a slight decline. Hydroxytyrosol and tyrosol contents in brines increased rapidly from the acidic hydrolysis of oleuropein, hydroxytyrosol-4-beta -d-glucoside, and salidroside, the concentrations of which decreased. Sorbate content decreased with time and disappeared completely in SF. Yeasts grew rapidly in FF and were markedly inhibited in SF. There was a moderate growth of lactic acid bacteria in FF, whereas they grew markedly in SF during the first few days. Some of these changes limit the shelf life of the product.