Alfredo Asensi

Nickel distribution in the hyperaccumulator Alyssum serpyllifolium Desf. spp. from the Iberian Peninsula

Abstract The relative concentration and distribution of nickel (Ni) in vegetative tissues (leaves, stems and trichomes) and reproductive organs (seeds) was studied using energy-dispersive X-ray microanalysis (EDXS) and scanning electron microscopy (SEM) in two previously studied Ni-hyperaccumulator subspecies of Alyssum serpyllifolium Desf. growing naturally in ultramafic soils of the Iberian Peninsula: A. serpyllifolium ssp. lusitanicum Dudley & P. Silva and A. serpyllifolium ssp. malacitanum Rivas Goday ex G. López. Both taxa showed that Ni accumulates preferentially in the leaves, exhibiting a homogeneous distribution on both epidermis surfaces. The highest Ni concentrations were found inside the epidermal cells and at the base of trichome stalks. Ni accumulation in seeds was lower than in the vegetative organs. The location of Ni in these plants allows us to postulate that its accumulation is a protection mechanism against external stress.

Copper uptake studies on Erica andevalensis, a metal‐tolerant plant from southwestern Spain

Abstract Pot trials and chemical analyses were carried out on wild specimens of Erica andevalensis Cabezudo et Rivera (Ericaceae) and their associated soils. Natural soils hosting E. andevalensis all had elevated copper concentrations. Pot trials showed that the Erica would grow in sulphide‐ore substrates containing up to 12,500 μg g‐1 (1.25%) copper, with or without amendment with EDTA. The addition of EDTA to these substrates increased the solubility of the copper to levels that killed other metal‐tolerant species (Biscutella laevigata and Brassica juncea), but not E. andevalensis. The copper concentrations in wild plants were only 1 to 24 μg g‐1 (dry weight) despite the high levels of copper (up to 3,676 μg g‐1) in the supporting soils. In the pot trials, the plant was able partially to exclude total copper up to 1,000 μg g‐1 in the soil. Thereafter, there was an exponential increase of copper in plant until the limit of tolerance was reached. Conclusions of the study were: (a) tolerance to copper by t...

Nickel localization in tissues of different hyperaccumulator species of Euphorbiaceae from ultramafic areas of Cuba

Pantropical species of the genera Phyllanthus and Euphorbia and the Cuban endemic genus Leucocroton from the Euphorbiaceae family, were selected for nickel localization microanalysis. Scanning Electron Microscopy coupled with Energy Dispersive X-ray Microanalysis (SEM-EDX) was used for qualitative detection of nickel in the selected Ni-hyperaccumulator species: Euphorbia helenae, Leucocroton linearifolius, L. flavicans Phyllanthus orbicularis, P. discolor and P. xpallidus, all collected from Cuban ultramafic soils. The leaves and stems from the Euphorbiaceae species analyzed were the organs with higher nickel accumulation. Elemental mapping of leaves and stem tissues from these species have been compared. The highest Ni concentrations were found in the laticifer tubes of stems and the epidermis tissues of leaves in all the analyzed species, suggesting a general pattern of the Euphorbiaceae family for nickel accumulation. The high nickel concentrations and its rather homogeneous distribution found in leaves of these Ni-hyperaccumulating plants suggest a possible role in protection mechanisms against environmental stress, such as UV irradiation.

Syntaxonomic analysis of theAndropogon-rich grasslands (Hyparrhenietalia hirtae) in the western Mediterranean region

Using the Braun-Blanquet approach, a syntaxonomical revision of the orderHyparrhenietalia hirtae in the western Mediterranean region was made. Various syntaxa were studied with relevés from the Iberian Peninsula, southern France, Sardinia, Sicily and adjacent islands, Balearic Islands, Canary Islands and Morocco. One alliance (Hyparrhenion hirtae), 8 associations (one of them new:Lotononido lupinifoliae-Hyparrhenietum sinaicae) and several subassociations and variants were distinguished. A complete classification of theHyparrhenietalia hirtae in the studied area with ecological and biogeographical diagnoses is given.

Sabulicolous therophytic plant cornrnunities "in the Mediterranean Region: a proposal of phytosociological synthesis

Therophytic non nirrophilous comrnunities growing on deep inland sandy soils and coastal dunes of me Mediterranean Region have been studied. We have summarised the current status of this type of vegetation, analysing the variability of described syntaxa, based on their floristic composition and geographic distribution. Al! avaiJable releves were arranged in a synthetic cable and subjected to a correspondence analysis (DCA). Two orders (Malcolmietalia aod Cutaodietalia maritimae), 8 alliances and 52 associa- tions were distinguished, A typological classification of mes e eommunities with ecologieal and biogeograph.ical diagnoses is given.

The coastal plant communities of Juniperus macrocarpa in the Mediterranean region

Juniperus macrocarpa is a threatened taxon growing on coastal areas of the Mediterranean region. A remarkable part of its communities are included in Juniperion turbinatae, considered as priority habitats for conservation in the Habitats Directive 92/43 EEC. We have summarized the current status of this type of vegetation, including the described associations of this alliance in order to analyse the variability of the syntaxa, based on its floristic composition and geographic distribution. The available relevés were arranged in a synthetic table and subjected to a detendred correspondence analysis. Two new suballiances (Juniperenion turbinatae and Asparago orientalis-Juniperenion macrocarpae) have been proposed. A typological classification of these communities with ecological and biogeographical diagnoses is given.

Saxifraga gemmulosa Boiss. (Saxifragaceae), an Endemic Nickel Bioindicator from Ultramafic Areas of the Southern Iberian Peninsula

Abstract The western Betic Mountain Range contains the largest ultramafic rock area in the Iberian Peninsula. The predominant flora of this southern territory (over two hundred taxa) was screened for Ni accumulation. Only two species showed important concentrations of Ni in their tissues, Alyssum serpyllifolium subsp. malacitanum (Brassicaceae), a Ni hyperaccumulator, and Saxifraga gemmulosa (Saxifragaceae). Saxifraga gemmulosa is a rare endemic species restricted to the ultramafic outcrops of Málaga (South Spain), mainly growing in basic or ultrabasic rock crevices, where it appears with other serpentinophytes such as Asplenium adiantum-nigrum subsp. corunnense (Aspleniaceae). Nickel and other representative elements present in Saxifraga gemmulosa and its soils from Sierra Bermeja (Málaga) were studied by inductively coupled plasma-mass spectrometry (ICP-MS). The structures of the plant were micromorphologically analysed by scanning electron microscopy (SEM) coupled to an Energy-Dispersive X-Ray Probe (EDX). The results showed the Ni hyperaccumulating characteristics of S. gemmulosa. As observed in other Ni hyperaccumulator plants, accumulation was mainly detected in leaf epidermis.

Alien plants of coastal dune habitats in southern Spain

Alien plants from psammophilous ecosystems have been studied in southern Spain. Sixteen sites, which are included in the Andalusian Network of Protected Spaces, have been chosen along 1100 km of Andalusian coasts in order to verify the degree of abundance and influence of these species on different communities. Out of the 26 localized species, the increase of some invasive plants, such as Arctotheca calendula, Agave americana, A. sisalana, Cortaderia selloana, Lantana camara and Opuntia dillenii, affects the conservation of some natural coastal ecosystems.

Las comunidades de Maytenus senegalensis subsp. europaeus (Celastraceae) en la Península Ibérica

Se estudian las comunidades que llevan Maytenus senegalensis subsp. europaeus (Boiss.) Rivas Mart. ex Guemes & M. B. Crespo en la Peninsula Iberica mediante el metodo fitosociologico de la escuela de Zurich-Montpellier. Se presentan sus caracteres ecologicos, biogeograficos y sintaxonomicos. Se aportan nuevas citas de este taxon y se describen como nuevos los siguientes sintaxones: Asparago albi-Rhamnetum oleoidis maytenetosum europaei, Odontito purpureae-Thymetum baetici teucrietosum almeriensis y Oleo sylvestris-Maytenetum europaei .

Morphological analysis, chorology and ecology of Juniperus navicularis Gand. in the Iberian Peninsula

Abstract Juniperus navicularis is an endemic taxon of Iberian Peninsula that develops on paleodunes of coastal ecosystems and whose distribution range is not well defined. In this paper, we present the results of the morphological analysis in populations attributed to J. navicularis of southern Spain. In order to assess the similarity between Portuguese and Spanish populations, the Mann–Whitney U test was performed, the same test was also applied between this taxon and Juniperus oxycedrus subsp. oxycedrus. In order to distinguish this species from other taxa of the Juniperus oxycedrus group (subsp. oxycedrus, subsp. badia, subsp. macrocarpa) in the southwestern Mediterranean region, a principal component analysis has been carried out. New data about the chorology and ecology of Spanish populations considered as a priority habitat in the Habitat Directive as well as number of individuals and conservation status are provided.