Percorrer por autor "Ferreira, V."
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- Molecular instability induced by aluminum stress in Plantago speciesPublication . Correia, S.; Matos, M.; Ferreira, V.; Martins, N.; Gonçalves, Sandra; Romano, Anabela; Pinto Carnide, O.Aluminum (Al) is one of the most abundant metals on earth's crust and Al toxicity represents one of the major factors that limit plant growth and productivity in acid soils (with a pH <= 5.0). In this study the mutagenic/genotoxic effects of Al were evaluated in roots and leaves of two Plantago, species, Plantago almogravensis and Plantago lagopus, using ISSRs markers. Both species were exposed to 400 mu M Al during 7 and 21 days. Ten ISSR primers produced polymorphic bands. In P. almogravensis, a total of 257 and 258 bands in roots and 255 and 265 bands in leaves were produced in the presence and absence of Al, respectively. In P. lagopus were produced 279 and 278 a total bands in roots and 275 and 274 bands in leaves, under the same conditions. The changes in ISSR profiles after Al treatment were considered as gain and/or loss of bands compared with the controls. The results suggest that changes in genomic template stability (GTS) could be detected with ISSR profiles. This molecular marker proved to be a good tool to detect the effects of Al on DNA profiles. It seems that Al did not interfere significantly with DNA integrity in both species but generated less ISSR stability in P. almogravensis than in P. lagopus. The results confirm the tolerance of P. almogravensis and suggest the same behavior of P. lagopus. Although further studies are required for confirmation the Al tolerance behavior of P. lagopus, a potential application for phytoremediation can be also considered due its wide distribution. (C) 2014 Elsevier B.V. All rights reserved.
- Spatial variability of soil properties and soil erodibility in the Alqueva reservoir watershedPublication . Ferreira, V.; Panagopoulos, Thomas; Andrade, R.; Guerrero, Carlos; Loures, L.The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.