Rafael Tomás

Universidad de La Rioja (Spain) | UNIRIOJA · Agriculture and Food

Simple Summary Air pollution in urban areas represents a major environmental risk to human and ecosystem health. Our aim was to test the adequacy of the Ligustrum lucidum physiological variables as proxies for heavy metal and platinum group element pollution. Chlorophyll, nitrogen and Fv/Fm generally showed high values typical of healthy plants, an...

Ultraviolet (UV) radiation strongly influences grape composition, but only a few studies have focused on how this influence is conserved in the resulting wines. Here we analyzed to what extent the changes induced by exposing Tempranillo grapes to UV radiation from budbreak to harvest were conserved in wine. By using different cut-off filters and la...

The effects of UV radiation on Vitis vinifera cv Tempranillo grapes were studied under field conditions as influenced by UV band (UV‐A and UV‐B), UV‐B level (ambient vs enhanced), grape phenological stage (pea‐size, veraison, and harvest), grape component (skin, flesh, and seeds), and fraction from which phenolic UV‐absorbing compounds (UVACs) were...

The liverwort Marchantia polymorpha subsp. ruderalis is an emerging model plant, and some data are available on its responses to ultraviolet (UV) radiation. However, it is unknown if the developmental stage of the thalli modulates the effects of UV radiation on the contents of potentially protecting phenolic compounds. To fill this gap, liverwort s...

Ultraviolet-B (UV-B) supplements have been applied to grapevine in controlled environments but not under field conditions, which would be the only way to manipulate UV-B to provide tangible agronomic benefits. Further, the effects of UV-B supplements should be investigated not only in grapes but also resulting wines, to check whether possible benef...

Agricultural intensification during the last century has caused river degradation across Europe. From the wide range of stressors derived from agricultural activities that impact rivers, diffuse agricultural pollution has received most of the attention from managers and scientists. The aim of this study was to determine the main stressors exerted b...

BACKGROUND It is widely recognized that ambient levels of solar ultraviolet (UV) radiation strongly influence the phenolic composition of grape skins. However, it is unknown to what extent this influence is reflected in the resulting wines. RESULTS Tempranillo grapevines were exposed or non‐exposed to close‐to‐ambient solar UV levels using appropr...

Agricultural intensification during the last century has produced river degradation across Europe. From the wide range of pressures derived from agricultural activities that impact rivers, diffuse agricultural pollution has received most of the attention from managers and scientists. The aim of this study was to determine the main pressures exerted...

We studied the effects of different radiation treatments on the physiology and UV-absorbing compounds of the model liverwort Marchantia polymorpha subsp. ruderalis. Starting from gemmae, samples were exposed to five radiation treatments: low photosynthetically active radiation (PAR), low PAR + UV-A, low PAR + UV-B, low PAR + UV-A + UV-B, and high P...

In the present study we assessed the effects of ambient solar UV exclusion on leaf physiology, and leaf and berry skin phenolic composition, of a major grapevine cultivar (Tempranillo) grown under typically Mediterranean field conditions over an entire season. In general, the effects of time were stronger than those of UV radiation. Ambient UV caus...

The International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation) was established in 1987. It is led by the UK and has its Programme Coordination Centre at the Centre for Ecology & Hydrology (CEH) in Bangor. It is one of seven ICPs and Task Forces that report to the Working Group on Effects (WGE) o...

In this study we determined the concentrations of As, Cd, Hg, Ni and Pb in samples of the moss Hypnum cupressiforme collected during 5 different sampling surveys (2006–2014) in a presumably unpolluted area in northern Spain (25 sampling sites). We then applied factor analysis (FA) to the data to explore the factors underlying the spatial and tempor...

The spatial variability of ultraviolet-absorbing compounds (UVACs) in the freshwater liverwort Jungermannia exsertifolia subsp. cordifolia was studied in mid-latitudes (the Atlantic-Mediterranean transition) across a wide lati-altitudinal gradient, with the aim of testing the usefulness of UVACs as biomarkers of current ambient levels of UV radiati...

The accumulation of ultraviolet-absorbing compounds (UVACs) within the cell walls of bryophytes provides a spatially uniform filter of ultraviolet-B (UV-B) radiation, and thus represents an important protective mechanism against its adverse effects. Here, the abilities of several cell-wall-degrading enzymes and of alkali (NaOH) in extracting cell-w...

A través de una encuesta, se han analizado las impresiones de los alumnos sobre la implantación del Modelo Mixto (presencial-virtual) en la asignatura de Biología durante el curso 2002-2003. La Biología corresponde al primer curso de Ingeniería Técnica Agrícola (especialidades de Hortofruticultura y Jardinería, e Industrias Agrarias y Alimentarias)...

The effects of enhanced UV-B radiation on UV-absorbing compounds (UVAC), the maximum quantum yield of photosystem II (Fv/Fm), DNA integrity, and the sclerophylly index, were analyzed in the mosses Bryum pseudotriquetrum and Fontinalis antipyretica. The study was performed for 31 days under laboratory conditions. Enhanced UV-B increased the bulk lev...

We studied, under laboratory conditions, the diel variations of DNA damage in response to changes in ultraviolet (UV) radiation in the liverwort Jungermannia exsertifolia subsp. cordifolia. The samples were exposed to three radiation regimes: P (only photosynthetically active radiation, PAR), PA (PAR + UV-A), and PAB (PAR + UV-A + UV-B). The day wa...

We studied the diel responses of the liverwort Jungermannia exsertifolia subsp. cordifolia to radiation changes under laboratory conditions. The samples were exposed to three radiation regimes: P (only PAR), PA (PAR+UV-A), and PAB (PAR+UV-A+UV-B). The day was divided in four periods: darkness, a first low-PAR period, the high-PAR plus UV period, an...

We examined the responses of ultraviolet-absorbing compounds (UVAC) to enhanced UV-B radiation in the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia for 31 days under laboratory conditions. Samples were exposed to three radiation regimes: P (only photosynthetic radiation), PA (photosynthetic + UV-A radiation) and PAB (photosynthetic...

We studied the relationships between environmental variables and the physiology of two (semi-)aquatic mosses (Bryum pseudotriquetrum and Fontinalis antipyretica) in an unforested headwater stream over a three year period. Neither environmental or physiological variables showed significant interannual variations. Most environmental variables (water...

We analyzed bulk UV absorbance of methanolic extracts and levels of five UV-absorbing compounds (hydroxycinnamic acid derivatives) in 135 herbarium samples of the liverwort Jungermannia exsertifolia subsp. cordifolia from northern Europe. Samples had been collected in 1850-2006 (96% in June-August). Both UV absorbance and compound levels were corre...

Temporal physiological variations in relation to environmental factors, in particular to ultraviolet (UV) radiation, have been studied in bryophytes from circumpolar latitudes, but not in mid-latitudes with longer growing seasons. In addition, seasonal and interannual changes in individual UV-absorbing compounds (UVAC) have not been previously stud...

Sun and shade samples of two aquatic bryophytes, the moss Fontinalis antipyretica and the liverwort Jungermannia exsertifolia subsp. cordifolia, were collected from a mountain stream and cultivated in the laboratory under two artificially imposed radiation regimes: control (only photosynthetically active radiation, PAR) and UV-B (PAR + UV-B). Sampl...

Bryophytes are important primary producers in mountain streams and they should be protected against the adverse effects of the high levels of UV-B radiation typical of these environments. The accumulation of UV-absorbing compounds could be one of the mechanisms of protection. A survey of methanol-extractable UV-absorbing compounds (MEUVAC) was cond...

The interaction between UV radiation and mineral availability has not been investigated in bryophytes, despite the important peculiarities of their mineral nutrition. The question under investigation was whether an improvement in phosphorus (P) availability, and the consequent increase in tissue P concentration, modified the responses to enhanced U...

The response of two cultivars of Vitis vinifera (Tempranillo and Viura) typical of La Rioja to current levels of ultraviolet-B (UV-B) radiation was evaluated. Plants were exposed to near ambient radiation (PAR + UV-A + UV-B) or near ambient radiation 95% depleted in UV-B. At the end of the 16-day exposure, diurnal variations in photosynthetic pigme...

Here we report the effects of a natural altitudinal gradient of UV-B radiation, from 1140 to 1816 m altitude, on the physiology of the aquatic liverwort Jungermannia exsertifolia Steph. subsp. cordifolia (Dumort.) Váña collected in mountain streams. Photosynthetic pigments, net photosynthesis and dark respiration rates, chlorophyll fluorescence, pr...

The aquatic liverwort Jungermannia exsertifolia subsp. cordifolia was cultivated for 15 d under controlled conditions to study the single and combined effects of cadmium and enhanced ultraviolet (UV) radiation. Both cadmium and UV radiation caused chlorophyll degradation and a decrease in the maximum quantum yield of photosystem II (PSII), together...

The depletion of the stratospheric ozone layer as a result of anthropogenic activities increases the ultraviolet-B (UV-B) irradiance at ground level. This may lead to harmful biological consequences affecting photosynthetic organisms. Mountain streams are especially exposed to a UV-B increase, and bryophytes play a key ecological role in them. In t...

The response of two cultivars of Vitis vinifera (Tempranillo and Viura) typical of La Rioja to current levels of ultraviolet-B (UV-B) radiation was evaluated. Plants were exposed to near ambient radiation (PAR + UVA + UV-B) or near ambient radiation 95% depleted in UV-B. At the end of the 16-day exposure, diurnal variations in photosynthetic pigmen...

We examined, under laboratory conditions, the influence of temperature (2 C vs. 10 C) on the physiological responses of two aquatic bryophytes from a mountain stream to artificially enhanced UV-B radiation for 82 d. These organisms may be exposed naturally to relatively low temperatures and high levels of UV-B radiation, and this combination is bel...

El adelgazamiento de la capa de ozono estratosférico como consecuencia de la emisión antropogénica de halocarburos está causando un aumento en la radiación ultravioleta-B (UV-B: 280-315 nm) que llega a la superficie terrestre. Para evaluar los efectos que este aumento puede tener sobre los briófitos acuáticos y su capacidad bioindicadora, se han cu...

The pollen deposits in four bogs north of Madrid, Spain, in the Morcuera Pass have been studied so as to determine vegetational dynamics in the area. Before 1440±110 BP the zone was densely forested primarily with Pinus, deciduous Quercus, and Betula. Since then marked human activity, mostly transhumance, has provoked progressive and generalized re...

The vegetation evolution in the easter sector during the last 2000 yr has been known by the polinic analyse realizad in the Puerto de la Morcuera (Sierra de Guadarrama-Madrid-). Thus, a forest more or less dense composed by Pinus, Quercus type decedeous and Betula was developed before 710 ± 90 BP. The mentioned forest was degrating, since the Roman...

The environmental impact that the building of the Pajares reservoir, started in 1986, has caused on the physical and chemical characteristics of the Iregua river (La Rioja, Spain) has been analyzed. Physicochcinical data of the sampling stations of Islallana (580 in on the Iregua river) and Torrcmontalbo (429 m on ihc Najerilla river, control stati...

Data regarding the origin and evolution of the genus Fagus have been obtained from the palynological study of four peat bogs located in the Macizo de Ayllon (Madrid-Guadalajara, Spain). There is evidence that the Fagus populations were present in the eastern area of the Spanish Sistema Central later than 2500 BP; and that they were more extended be...

Towards 2580 ± 80 BP the principal forest of the Canencia Pass was dense birchwood. Pinus was located at higher elevations while Quercus pyrenaica, was found at lower elevations. At around 1170 ± 50 BP Betula, as well as the Pinus and Quercus woods, began to recede indicating the existence of pasturage in the zone. Grazing would have extended to th...

Pollen analysis has been carried out on three peat-bogs in order to determine vegetation changes during the 19th century. A gradual forest degradation caused by a strong human influence, mainly through sheep-grazing activities, has been assessed. However, a slow recovery of the tree layer has been detected in the most recent pollen levels, as a con...

L'analyse pollinique effectuée dans des dépôts tourbeux PM III et PM VIII, situés au Col de Morcuera (Sierra de Guadarrama, Madrid) a permis de connaître l'évolution de la végétation dans le secteur oriental du Système Central pendant les 2 000 dernières années. Avant 1710 +- 90 BP, il s'est développé une forêt assez compacte composée par Pinus, Qu...