77 research outputs found
Strategies in a metallophyte species to cope with manganese excess
The effect of exposure to high Mn concentration
was studied in a metallophyte species, Erica
andevalensis, using hydroponic cultures with a range
of Mn concentrations (0.06, 100, 300, 500, and
700 mg L-1). At harvest, biomass production, element
uptake, and biochemical indicators of metal
stress (leaf pigments, organic acids, amino acids,
phenols, and activities of catalase, peroxidase, superoxide
dismutase) were determined in leaves and roots.
Increasing Mn concentrations led to a decrease in
biomass accumulation, and tip leaves chlorosis was
the only toxicity symptom detected. In a similar way,
photosynthetic pigments (chlorophylls a and b, and
carotenoids) were affected by high Mn levels. Among
organic acids, malate and oxalate contents in roots
showed a significant increase at the highest Mn
concentration, while in leaves, Mn led to an increasing
trend in citrate and malate contents. An increase of Mn also induced an increase in superoxide dismutase
activity in roots and catalase activity in leaves. As
well, significant changes in free amino acids were
induced by Mn concentrations higher than
300 mg L-1, especially in roots. No significant
changes in phenolic compounds were observed in
the leaves, but root phenolics were significantly
increased by increasing Mn concentrations in treatments.
When Fe supply was increased 10 and 20 times
(7–14 mg Fe L-1 as Fe-EDDHA) in the nutrient
solutions at the highest Mn concentration
(700 mg Mn L-1), it led to significant increases in
photosynthetic pigments and biomass accumulation.
Manganese was mostly accumulated in the roots, and
the species was essentially a Mn excluder. However,
considering the high leaf Mn concentration recorded
without toxicity symptoms, E. andevalensis might be
rated as a Mn-tolerant speciesinfo:eu-repo/semantics/publishedVersio
Review of cleaning techniques and their effects on the chemical composition of foliar samples
Chemical foliar analysis is a tool widely used to study tree nutrition and to monitor the impact and extent of air pollutants. This paper reviews a number of cleaning methods, and the effects of cleaning on foliar chemistry. Cleaning may include mechanical techniques such as the use of dry or moistened tissues, shaking, blowing, and brushing, or use various washing techniques with water or other solvents. Owing to the diversity of plant species, tissue differences, etc., there is no standard procedure for all kinds of samples. Analysis of uncleaned leaves is considered a good method for assessing the degree of air contamination because it provides an estimate of the element content of the deposits on leaf surfaces or when the analysis is aimed at the investigation of transfer of elements along the food chain. Sample cleaning is recommended in order (1) to investigate the transfer rate of chemical elements from soil to plants, (2) to qualify the washoff of dry deposition from foliage and (3) to separate superficially absorbed and biomass-incorporated elements. Since there is not a standard cleaning procedure for all kinds of samples and aims, it is advised to conduct a pilot study in order to be able to establish a cleaning procedure to provide reliable foliar data
Is it healthy urban agriculture? Human exposure to potentially toxic elements in urban gardens from Andalusia, Spain
17 páginas.- 5 figuras.- 4 tablas.- referencias.-The online version contains supplementary material available at https://doi.org/10.1007/s11356-024-33500-wDifferent vegetable species and topsoils were collected from different urban gardens of Seville, Cordoba, and Huelva (South Spain) and from two small towns in a mining area (Riotinto), together with topsoil close to the plants. The concentration of potentially toxic elements (PTEs) (As, B, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn) was evaluated in edible plant parts and in the soils. The same species were also purchased from Seville local markets and from a peri-urban area (domestic garden in a rural area) and also analyzed. Plant/soil pollution relation was studied and human health risk was assessed by different parameters. Soils of urban gardens from the mining area were more contaminated with As, Cr, Cu, Pb, and Zn in comparison with other locations, and generally, soils from cities showed higher values of As, Pb, and Zn than the peri-urban ones. The mean concentration of almost all potentially toxic elements was higher in leafy than in fruiting and bulbous species. Arsenic, Cd, and Pb concentrations were below health-based guidance values in all vegetables except Cd in one sample in the peri-urban area. In general, PTEs concentration in vegetables from city urban gardens did not exceed the one found in market vegetables for almost all studied elements, except in lettuce for almost elements. The hazard quotient (HQ) values were lower than the unit for all PTEs in plant species from the studied gardens, as well as the hazard index (HI), indicating that consumption of these vegetables can be considered safe and without risk to human health. Also, cancer risk values for As were below the established limits in all vegetables from the studied urban gardens, including those from the As-contaminated soils in the mining area.Funding for open access publishing: Universidad de Sevilla/CBUA This work was supported by The Plan Propio de la Universidad de Sevilla “Proyecto Precompetitivo” and was partially funded by the University of Seville (Plan Propio 2021/22 Project 2021/1270) and CSIC-IRNAS.Peer reviewe
Accumulation and in vivo tissue distribution of pollutant elements in Erica andevalensis
Erica andevalensis is an endemic shrub from an area in the southwest of Spain (Andalucia) characterized by acidic and contaminated soils. Scanning electron microscopy (SEM) of samples after conventional or cryo-fixation preparation protocols was used for morphological and anatomical studies. SEM coupled with EDX-analysis was employed to localise and quantify different elements within plant parts (leaves, stems and roots) in samples collected in the field. Morphological studies revealed that the species has typical adaptive structures to drought-stress such as rolled needle-like leaves, sunken stomata and a thick waxy cuticle on the upper epidermis. Roots were associated with fungi which formed intra and extra-cellular mycelia. The SEM studies showed that Cu was not sequestrated into the root tissues and was uniformly distributed in leaf tissues. Meanwhile, Pb was only localised within epidermal root tissues which indicates that its sequestration in an external matrix might represent a tolerance mechanism in this species. Iron was uniformly distributed throughout the leaves, while in roots it was predominantly retained on the epidermal cell walls. The exclusion and tolerance mechanisms adopted by this species to survive in mining areas indicate that it can be used successfully in the re-vegetation of contaminated areas.Peer Reviewe
Germination responses of Erica andevalensis to different chemical and physical treatments
7 pages, 4 figures, 1 table.-- Available online Aug 12, 2008.Erica andevalensis Cabezudo & Rivera is a threatened edaphic endemic species of Andalusia (SW Spain). Under natural conditions, the plants produce a very large number of small seeds (0.3–0.4 mm) but very few seedlings survive. Different treatments (high temperature, cold pre-treatment, nitrogen salts, and gibberellic acid applications) were tested to assess germination patterns in different populations and to determinate the most favorable conditions for germination. Gibberellic acid was provided in five different concentrations from 0 to 400 ppm GA3, while nitrogen was applied as 10 mM of either KNO3 or NH4NO3. The effect of pH on germination was also tested. The species always showed a low germination rate (6.50–22%) that was not stimulated either by 1 or 4 months in dry cold pre-treatment, nitrogen application, acid pH medium, or by high temperature (80°C for 10 min); although gibberellic acid application (100–400 ppm) significantly enhanced germination. The highest percentage of germination (41.6%) was achieved with a mean germination time to start germination (t-0) of 7.6 ± 0.54 days when the seeds were subjected to 400 ppm gibberellic acid treatment. The population origin did not have a significant effect on germination percentage.The present research was supported in part by
the Spanish Ministry of Science and Education (CGL2006/02860) and in part by Fundación Areces (Proyect title: Mecanismos de resistencia a metales pesados en especies significativas de la cuenca minera de Riotinto).Peer reviewe
Tolerance to high Zn in the metallophyte Erica andevalensis Cabezudo & Rivera
The tolerance to high Zn was studied in the metallophyte Erica andevalensis Cabezudo & Rivera grown in nutrient solutions at different Zn concentrations (5, 500, 1,000, 1,500 and 2,000 οM Zn). Plant growth and nutrient uptake were determined. Metabolic changes were assessed by the analysis of peroxidase activity, organic metabolites related to metal chelation (amino acids, organic acids (malate, citrate) or protection (polyamines). While plants tolerated up to 1,500 lM Zn, despite presenting of low growth rates, the concentration of 2,000 lM Zn was toxic producing high mortality rates. Roots accumulated high Zn concentration (11,971 mg/kg) at 1,500 lM external Zn) apparently avoiding metal transfer into shoots. After 30 days of treatment with high Zn (1,000 and 1,500 lM Zn), the leaves accumulated high levels of glutamine. Shortterm treatment with 500 lM Zn, significantly increased the concentration of asparagine and glutamine in roots. Citrate concentration was also considerably increased when exposing roots to Zn excess. Metal immobilization in the root system, low interference with the uptake of nutrients and an increased production of putative organic ligands (amino acids, citrate) might have provided the Zn tolerance displayed by Erica andevalensis.This research was supported by Spanish Ministry of Science and Education (MEC) (CGL2006-1,418 and José Castillejo Program) and Ramón Areces Foundation.Peer Reviewe
A review of hazardous elements tolerance in a metallophyte model species: Erica andevalensis
9 páginas.-- 5 figuras.-- 2 tablas.-- referenciasAs a result of mining activities large portions of land have been degraded. In this work, different tolerance/resistance mechanisms of Erica andevalensis Cabezudo y Rivera, which allow thriving and growing in soils from mine areas enriched with potentially toxic elements are reported. Different strategies were identified in E. andevalensis to tolerate high concentrations of metal(loid)s in soils through field and laboratory studies. The response of this species to high concentrations of hazardous elements varies according to the element. Experimental evidence for E. andevalensis adaptation to polluted soils/sediments and the role of other chemical elements (e.g. silicon) to enhance metal(loid)s tolerance is described. The species acts as an excluder for almost all elements and its tolerance to the harsh environments is due to complex mechanisms that include defense and avoidance.This research was supported by Spanish Ministry of Science and Education (MEC) (CGL2006-1418 and José Castillejo Program) and Ramón Areces Foundation. This work was also developed in the scope of the projects LEAF (Linking Landscape, Environment, Agriculture and Food Research Centre) – Instituto Superior de Agronomia, Universidade de Lisboa (FCT-UID/AGR/04129/2013), financed by the FCT/MEC through national funds and co-financed by the FEDER within the PT2020 Partnership Agreement.Peer reviewe
Effects of silicon on copper toxicity in Erica andevalensis Cabezudo and Rivera: a potential species to remediate contaminated soils
The influence of silicon on responses to copper excess was studied in plants of Erica andevalensis. Plantlets were grown in nutrient solutions containing two Cu (1 and 500 M) and three Si concentrations (0, 0.5 and 1 mM). Plant growth, water content, and mineral nutrient concentration were determined. Plants grown with 500 M Cu showed differences in growth and shoot water content depending on Si supply. The addition of 1 mM Si in high-Cu nutrient solutions significantly improved plant growth and reduced water loss preventing plant death related to Cu-excess. Silicon supply reduced significantly leaf Cu concentration (up to 32%) and increased Cu concentration in roots. Phytoliths isolated from leaves were analysed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Such phytoliths consisted in silica deposits associated with Cu and other elements (K, Ca, P). Improvement by Si of Cu tolerance in E. andevalensis was clearly related to the inhibition of Cu upward transport. The leaf phytoliths formed in Si-treated plants might have some contribution to tolerance by Cu immobilisation and inactivation.Peer Reviewe
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