Metal Concentrations In Leaves Research Articles

Mapping leaf metal content over industrial brownfields using airborne hyperspectral imaging and optimized vegetation indices

Monitoring plant metal uptake is essential for assessing the ecological risks of contaminated sites. While traditional techniques used to achieve this are destructive, Visible Near-Infrared (VNIR) reflectance spectroscopy represents a good alternative to monitor pollution remotely. Based on previous work, this study proposes a methodology for mapping the content of several metals in leaves (Cr, Cu, Ni and Zn) under realistic field conditions and from airborne imaging. For this purpose, the reflectance of Rubus fruticosus L., a pioneer species of industrial brownfields, was linked to leaf metal contents using optimized normalized vegetation indices. High correlations were found between the vegetation indices exploiting pigment-related wavelengths and leaf metal contents (r ≤ − 0.76 for Cr, Cu and Ni, and r ≥ 0.87 for Zn). This allowed predicting the metal contents with good accuracy in the field and on the image, especially Cu and Zn (r ≥ 0.84 and RPD ≥ 2.06). The same indices were applied over the entire study site to map the metal contents at very high spatial resolution. This study demonstrates the potential of remote sensing for assessing metal uptake by plants, opening perspectives of application in risk assessment and phytoextraction monitoring in the context of trace metal pollution.

Plant metal concentrations in Theobroma cacao as affected by soil metal availability in different soil types

Beans of cacao (Theobroma cacaoL.) are used to produce a variety of chocolate products. Bioaccumulation of metals at toxic levels through the consumption of contaminated products has been identified as a health concern in humans. Both metal diversity and concentration as well as their interactions in the soil influence essential and non-essential metal uptake in plants; but the effects of these on bioaccumulation of metals in cacao is not understood across diverse soil types. In this study eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were investigated in 12 soil subgroups belonging to four soil orders across 15 locations in Trinidad, with the aim to investigate the effect of soil metal diversity and concentration on metal bioaccumulation in cacao. Soil metals were extracted using five methods (aqua regia, DTPA, Mehlich 3, nitric acid, and water). Cacao leaf metal concentrations were determined using the USEPA 3052 method. Metal extraction efficiency ranged between methods with aqua regia ≥ nitric acid > Mehlich 3 ≥ DTPA ≥ water across all metals. The soil extraction method that best predicted cacao leaf metal concentrations varied with the metal – Mehlich 3 or DTPA for Cd, Ni, Zn; aqua regia, Mehlich 3, or nitric acid for Pb, and water for Mn. A stepwise regression analysis showed that plant metal concentration can be predicted using soil physicochemical characteristics as well as the concentration of metals in the soil. The importance of soil type on cacao leaf metal bioaccumulation is discussed.

Impact of metal accumulation on Quercus ilex L. leaf traits

The aims of this research were: i) to compare Cr, Cu, Ni and Pb concentrations in Quercus ilex L. leaves collected at urban/industrial and urban areas; ii) to investigate the main pathway of leaf metal accumulation; iii) to evaluate probable differences in traits of leaves at the investigated area typologies; iv) to relate leaf metal concentrations and to leaf traits. Leaves and soils were collected at six sites (three of urban area and three of urban/industrial area). Length, width, area, extract pH, relative water content, specific area and petiole length were evaluated in the leaves; besides, Cr, Cu, Ni and Pb concentrations were measured in unwashed and chloroform washed leaves, and in soils. The comparison between leaves collected at the urban and urban/industrial area showed that higher Cr, Ni and Pb concentrations were measured at the urban/industrial area, greater leaves and longer petiole were observed at the urban area, whereas higher leaf extract pH were observed at the urban/industrial one. Air uptake seemed to be the main pathway of leaf metal accumulation, as soils were not metal contaminated. Q. ilex leaves highlighted a diffuse and conspicuous air metal pollution in both urban/industrial and urban areas, although differences between the site typologies were observed. In fact, leaves of the urban/industrial area showed higher inner concentrations of all the investigated metals, with the exception of Cu. A direct leaf uptake by the air can be supposed, as the soils were scarcely metal contaminated. Greater leaves and longer petiole, among the investigated leaf traits, appeared the main leaf responses to metal accumulation.

Natural Variation in Physiological Responses of Tunisian Hedysarum carnosum Under Iron Deficiency.

Iron (Fe) is an essential element for plant growth and development. The cultivation of leguminous plants has generated strong interest because of their growth even on poor soils. Calcareous and saline soils with poor mineral availability are wide-spread in Tunisia. In an attempt to select better forage crops adapted to Tunisian soils, we characterized Fe deficiency responses of three different isolates of Hedysarum carnosum, an endemic Tunisian extremophile species growing in native stands in salt and calcareous soil conditions. H. carnosum is a non-model crop. The three isolates, named according to their habitats Karkar, Thelja, and Douiret, differed in the expression of Fe deficiency symptoms like morphology, leaf chlorosis with compromised leaf chlorophyll content and photosynthetic capacity and leaf metal contents. Across these parameters Thelja was found to be tolerant, while Karkar and Douiret were susceptible to Fe deficiency stress. The three physiological and molecular indicators of the iron deficiency response in roots, Fe reductase activity, growth medium acidification and induction of the IRON-REGULATED TRANSPORTER1 homolog, indicated that all lines responded to -Fe, however, varied in the strength of the different responses. We conclude that the individual lines have distinct adaptation capacities to react to iron deficiency, presumably involving mechanisms of whole-plant iron homeostasis and internal metal distribution. The Fe deficiency tolerance of Thelja might be linked with adaptation to its natural habitat on calcareous soil.

Metal concentrations in seagrass (Halophila ovalis) tissue and ambient sediment in a highly modified estuarine environment (Sydney estuary, Australia)

Research into sediment-seagrass tissue metal relationships has been undertaken in Sydney estuary due to the recognized role contamination plays in threats to seagrass health. Seagrass (Halophila ovalis) leaf tissue concentrations are elevated in Cu, Pb and Zn and contain the highest reported root Cr concentrations. Seagrass metal concentrations were significantly different between species H. ovalis and Zostera capricorni; between root and leaf tissue; and between sampling locations. Greatest tissue enrichment was for Pb, however metals were not enriched in seagrass relative to surficial sediment. Fine and total sediment metal concentrations were temporally consistent between collection years 2013/15, whereas root tissue metals changed between years and sites and leaf metal contents were temporally inconsistent. Extractable metal concentrations in fine sediment (<62.5 μm) showed moderate significant correlation with root tissue and a weak significant relationship with leaf tissue, whereas total sediment metal showed no such relationships. Management implications are provided.

Community variation in plant traits along copper and cobalt gradients

AbstractQuestionsHow do resource acquisition‐related traits and stress tolerance‐related traits shift along Cu and Co gradients? What are the relative contributions of species turnover and intraspecific variation in driving these shifts?LocationFungurume V hill, Katanga province, Democratic Republic of Congo.MethodsWe measured five functional traits (vegetative height, leaf area, specific leaf area (SLA) and leaf Cu and leaf Co concentration) related to resource acquisition, competitive ability and metal tolerance strategy for 37 of the most abundant species from 32 plots along natural Cu and Co gradients (from 92 to 6737 mg·kg−1 and 10 to 655 mg·kg−1, respectively). Linear regression was applied to analyse species‐level and community‐level changes in these traits along the study gradients. Using variance decomposition, we evaluated the relative contribution of intraspecific variation and species turnover to the total community variation along the Cu gradient.Results and ConclusionsAt the community level, plant height and leaf area decreased while SLA and leaf metal concentrations increased with increasing soil metal concentration. At the species level, patterns were often idiosyncratic and lacked generality. As a result, species turnover was the predominant factor explaining community‐level variation along the study gradients, which was particularly clear for variation in leaf Cu concentration. This reflects the constitutive ability of some species to exclude metal, while other species can tolerate high metal concentrations in their leaves. The study emphasizes the importance of evaluating the origin of phenotypic variations observed at the community level.

Wounding of Arabidopsis halleri leaves enhances cadmium accumulation that acts as a defense against herbivory.

Approximately 0.2 % of all angiosperms are classified as metal hyperaccumulators based on their extraordinarily high leaf metal contents, for example >1 % zinc, >0.1 % nickel or >0.01 % cadmium (Cd) in dry biomass. So far, metal hyperaccumulation has been considered to be a taxon-wide, constitutively expressed trait, the extent of which depends solely on available metal concentrations in the soil. Here we show that in the facultative metallophyte Arabidopsis halleri, both insect herbivory and mechanical wounding of leaves trigger an increase specifically in leaf Cd accumulation. Moreover, the Cd concentrations accumulated in leaves can serve as an elemental defense against herbivory by larvae of the Brassicaceae specialist small white (Pieris rapae), thus allowing the plant to take advantage of this non-essential trace element and toxin. Metal homeostasis genes are overrepresented in the systemic transcriptional response of roots to the wounding of leaves in A. halleri, supporting that leaf Cd accumulation is preceded by systemic signaling events. A similar, but quantitatively less pronounced transcriptional response was observed in A. thaliana, suggesting that the systemically regulated modulation of metal homeostasis in response to leaf wounding also occurs in non-hyperaccumulator plants. This is the first report of an environmental stimulus influencing metal hyperaccumulation.Electronic supplementary materialThe online version of this article (doi:10.1007/s10534-015-9829-9) contains supplementary material, which is available to authorized users.

PENENTUAN KANDUNGAN LOGAM ESENSIAL (Fe, Zn DAN Cu) DALAM DAUN SIRIH MERAH (Piper crocatum) SEGAR, AIR REBUSAN DAN AIR SEDUHANNYA DENGAN METODE SPEKTROSKOPI SERAPAN ATOM(SSA)

Vol 7 No 2ABSTRACTDetermination of essential metals (Fe, Zn and Cu) in red betel leaf has been carried out by usingAtomic Absorption Spectrophotometer (AAS). Fresh and dry red betel leaf extracted in 75 mLby boiled and brewed distilled water for 5, 10, 15 and 20 minutes. In the fresh red betel leafmetal content (Fe, Zn and Cu) were 0,3257 %, 0,173 % and 0,0278 % and the highest metalcontent (Fe, Zn and Cu) found in dry red betel leaf which were boiled for 20 minutes with theconcentration 0,0539 %, 0,0305 % and 0,0128 %. Red betel leaf is a source of essential metalsneeded by the body.Keywords: Atomic Absorption Spectrophotometry (AAS), Red betel leaf (Piper crocatum),decoction water, steeping water, Fe, Zn and Cu

Genotypic variations in the dynamics of metal concentrations in poplar leaves: A field study with a perspective on phytoremediation

Poplar is commonly used for phytoremediation of metal polluted soils. However, the high concentrations of trace elements present in leaves may return to soil upon leaf abscission.To investigate the mechanisms controlling leaf metal content, metal concentrations and expression levels of genes involved in metal transport were monitored at different developmental stages on leaves from different poplar genotypes growing on a contaminated field.Large differences in leaf metal concentrations were observed among genotypes. Whereas Mg was remobilized during senescence, Zn and Cd accumulation continued until leaf abscission in all genotypes. A positive correlation between Natural Resistance Associated Macrophage Protein 1 (NRAMP1) expression levels and Zn bio-concentration factors was observed. Principal component analyses of metal concentrations and gene expression levels clearly discriminated poplar genotypes.This study highlights a general absence of trace element remobilization from poplar leaves despite genotype specificities in the control of leaf metal homeostasis.

Investigations of Heavy Metals Concentrations in Leaves of Telfairia occidentalis Hook. F. (Fluted Pumpkin) in Nigeria

Investigations of Heavy Metals Concentrations in Leaves of Telfairia occidentalis Hook. F. (Fluted Pumpkin) in Nigeria

Olive mill waste biochar: a promising soil amendment for metal immobilization in contaminated soils.

The potential use of biochar from olive mill waste for in situ remediation of metal contaminated soils was evaluated. Biochar was mixed with metal contaminated soil originating from the vicinity of an old zinc smelter. Soil-biochar mixtures were equilibrated for 30 and 90 days. At these time points, Ca(NO3)2 exchangeable metals were determined, and effects of the biochar amendment on soil toxicity were investigated using plants, bacteria, and earthworms. Bean (Phaseolus vulgaris) growth, metal content, antioxidative enzymes activities, and soluble protein contents were determined. Furthermore, effects on soil microbial communities (activity, diversity, richness) were examined using Biolog ECOplates. After 120 days of soil-biochar equilibration, effects on weight and reproduction of Eisenia foetida were evaluated. With increasing biochar application rate and equilibration period, Ca(NO3)2 exchangeable metals decreased, and growth of bean plants improved; leaf metal contents reduced, the activities of antioxidative stress enzymes decreased, and soluble protein contents increased. Soil microbial activity, richness, and diversity were augmented. Earthworm mortality lowered, and their growth and reproduction showed increasing trends.

Dynamics of Cu, Mn, Ni, Sr and Zn release during decomposition of four types of litter in headwater riparian forests in northern Poland

Abstract The aim of the study was to compare the dynamics of Cu, Mn, Ni, Sr and Zn release during decomposition of leaves of Black alder (native material), Norway maple, Red oak and European beech (exogenous material) in the area of headwater riparian forests along the upper course of the Kamienna Creek (Northern Poland). Litter bag method was used in the experiment. Initial materials differed in terms of their chemical composition. Cu, Mn, Ni, Sr and Zn contents were low in general, and in fact, even a few times lower than limit values for decomposition rate. Different trends in the dynamics of the leaf metal content during decomposition were observed in particular tree species despite the fact, that every materials were exposed in the same site. Release dynamics was strongly affected by the content of metals in initial materials and in topsoil. Accumulation of Cu, Mn and Zn was observed during decomposition of poorest in the elements maple leaves, as well as Ni in alder leaves and Sr in the leaves of maple, alder and oak. In beech leaves we observed intensive leaching of Ni, whereas downward trends in the Cu concentration of beech leaves, as well as Mn and Zn in beech and oak leaves, were related to weight loss of the leaves. In some cases, the dynamics of metal release displayed a more complicated two- or three-stage character (release of Ni from maple and oak leaves; Cu from maple leaves; Sr from alder, maple and oak leaves; and Zn from alder and maple leaves).

Zinc and cadmium hyperaccumulation act as deterrents towards specialist herbivores and impede the performance of a generalist herbivore

Extraordinarily high leaf metal concentrations in metal hyperaccumulator plants may serve as an elemental defence against herbivores. However, mixed results have been reported and studies using comparative approaches are missing. We investigated the deterrent and toxic potential of metals employing the hyperaccumulator Arabidopsis halleri. Effects of zinc (Zn) and cadmium (Cd) on the preferences of three Brassicaceae specialists were tested in paired-choice experiments using differently treated plant material, including transgenic plants. In performance tests, we determined the toxicity and joint effects of both metals incorporated in an artificial diet on the survival of a generalist. Feeding by all specialists was significantly reduced by metal concentrations from above 1000μgZng(-1) DW and 18μgCdg(-1) DW. By contrast, metals did not affect oviposition. Generalist survival decreased with increasing concentrations of individual metals, whereby the combination of Zn and Cd had an additive toxic effect even at the lowest applied concentrations of 100μgZng(-1) and 2μgCdg(-1) . Metal hyperaccumulation protects plants from herbivory resulting from deterrence and toxicity against a wide range of herbivores. The combination of metals exacerbates toxicity through joint effects and enhances elemental defence. Thus, metal hyperaccumulation is ecologically beneficial for plants.

Heavy metal contamination of spontaneous vegetation and soil around the copper smelter "Legnica"

The area around the copper smelter "Legnica" in western Poland is influenced by pollutants from the smelter for about 35 years. Ecosystems within a distance of 1-2 km from the smelting complex are heavily degradated. Copper levels of the upper soil layers averaged more than 15000 ppm, lead levels more than 2000 ppm (d.m. weight). Besides heavy metals, sulphur dioxide is one of the most important pollutants affecting plant growth. Only few plant species are able to grow on those highly contaminated sites. Vegetation patches within zones of bare ground without any vegetation are mainly dominated by &lt;i&gt;Convolvulus arvensis&lt;/i&gt;, &lt;i&gt;Agropyron repens&lt;/i&gt;, &lt;i&gt;Calamagrostis epigeios&lt;/i&gt; or &lt;i&gt;Sambucus nigra&lt;/i&gt;. Leaf metal contents of &lt;i&gt;Artemisia vulgaris&lt;/i&gt;, a plant which is a good bioindicator and also very frequent around the copper smelter, ranged: 665-2340 ppm Cu (d.m. weight), 215-2301 ppm Zn, 189-1031 ppm Pb and 0.75-12.4 ppm Cd according to the distance and exposition to the pollution source.

Effects of Combined Drought and Heavy Metal Stresses on Xylem Structure and Hydraulic Conductivity in Red Maple (Acer rubrum L.)

The effects of heavy metal stress, drought stress, and their combination on xylem structure in red maple (Acer rubrum) seedlings were investigated in an outdoor pot experiment. As metal-contaminated substrate, a mixture of 1.5% slag with sand was used, with Ni, Cu, Co, and Cr as the main contaminants. Plants grown on contaminated substrate had increased leaf metal concentrations. The two stresses reduced plant growth in an additive manner. The effects of metal and drought stresses on xylem characteristics were similar to each other, with a reduced proportion of xylem tissue, reduced conduit density in stems, and reduced conduit size in the roots. This resulted, in both stems and roots, in reductions in hydraulic conductance, xylem-specific conductivity, and leaf-specific conductivity. The similarity of the responses to the two stresses suggests that the plants' response to metals was actually a drought response, probably due to the reduced water uptake capacity of the metal-exposed roots. The only plant responses specific to metal stress were decreasing trends of stomatal density and chlorophyll content. In conclusion, the exposure to metals aggravates water stress in an additive manner, making the plants more vulnerable to drought.

Early changes in the fatty acid composition of photosynthetic membrane lipids from Populus nigra grown on a metallurgical landfill

We compared the fatty acid composition of leaves taken from poplars on a metal-contaminated landfill, and on the uncontaminated roadside bordering this site. For the first time, it is shown that the percentage of linolenic acid, which is mainly associated with thylakoid lipids, was significantly lower in tree species within the landfill than within the control area. A correlation study was carried out to investigate relationships between the C18:3/(C18:0+C18:1+C18:2) fatty acid ratios and the metal contents in soils and leaves. Lead and chromium leaf contents were significantly negatively correlated to this fatty acid ratio. The impact of each of these metals remains difficult to evaluate, but chromium in leaf likely plays a major role in toxicity. In addition, the decrease in the C18:3/(C18:0+C18:1+C18:2) fatty acid ratio occurred at low leaf metal content, and therefore it is shown that this ratio can be used as an early indicator of the effect of metals.

Effect of air-borne heavy metals on the biochemical signature of tree species in an industrial region, with an emphasis on anticipated performance index

The present study demonstrates elevated concentrations of air-borne heavy metals (Fe, 4.791; Cr, 3.142; Pb, 1.718; Cd, 0.069 μg·m−3) in an industrial region and their subsequent accumulation in tree species grown in that area. Lagerstomia speciosa showed the highest leaf metal concentrations, whereas the lowest metal concentration was observed in Acacia moniliformis. Air accumulation factors (AAF) for heavy metals were in the sequence Cd>Cr>Pb>Fe. Plants exposed to air-borne heavy metals showed a significant (p<0.01, p<0.05) decrease in total chlorophyll and soluble sugars content, with higher synthesis of cellular antioxidants compared with ascorbic acids, proline and thiols (NP-SH). Plants with higher air-borne metal accumulation factors (AAF) generally have a high air pollution tolerance index (APTI) value. Assessment of the anticipated performance index (API) gave Alstonia scholaris as the ‘best variety’ and A. moniliformis and Shorea robusta as ‘very good’ for plantation and greenbelt development in an industrial region.

Accumulation and Distribution of Metals in Bolboschoenus maritimus (Cyperaceae), from a South African River

The Diep River is a major freshwater ecosystem in the Western Cape, South Africa. Although it is surrounded by many sources of metal pollution, the actual metal levels in this river system are unknown. Wetland plants are known to accumulate metals and may possibly be used as biomonitors of metal contamination in a river system. One such species, the sedge Bolboschoenus maritimus, is found in abundance along the banks of this river. The aim of this study was to investigate and monitor the degree of metal contamination in the water and sediments of the lower Diep River, as well as to study the seasonal accumulation and distribution of metals in B. maritimus, and the use thereof as biomonitor species. Two sampling sites were used: one site above the wetland section of the river, receiving runoff mainly from agricultural lands (site 1), and one site close to the river mouth (site 2), exposed to several possible pollution sources. Water, sediment, and plant (root, leaf and stem) samples were collected seasonally for 1 year and analyzed for Al, Zn, Cu, and Fe. There was greater bioaccumulation of metals by plants at site 2, due to greater bioavailability of metals. B. maritimus was shown to be a root accumulator of metals. Seasonal fluctuations in root, stem, and leaf metal concentrations did not follow seasonal sediment concentration patterns. However, using B. maritimus as test species did provide valuable additional information to sediment and water analyses. More extensive research is needed to conclude whether this species is an effective biomonitor in the lower Diep River environment.

Spatial distribution of cadmium in leaves and its impact on photosynthesis: examples of different strategies in willow and poplar clones

The interaction of cadmium (Cd) with photosynthesis was investigated in poplar (Populus x canadensis Mönch., clone A4A, Populus nigra L., clone Poli) and willow (Salix alba L., clone SS5) clones that had different leaf metal concentrations in preliminary experiments. Plants grown in the presence of 50 microm CdSO(4) for 3 weeks under hydroponic conditions were used to examine leaf gas exchange, chlorophyll fluorescence parameters and images, and for Cd detection using energy dispersive X-ray fluorescence (ED-XRF). Leaves were finally analysed for Cd and phytochelatin concentrations. Results showed that SS5 had the highest leaf Cd concentration and high gas exchange activity similar to that of Poli, which had the lowest Cd concentration. Leaf fluorescence images evidenced in large undamaged areas of SS5 corresponded to high values of F(v)/F(m), F(o), PhiPSII, qP and NPQ, while patches of dark colour (visible necrosis) close to the main vein corresponded to low values of these parameters. In A4A, these necrotic patches were more diffuse on the leaf blade and associated with a range of fluorescence parameter values. ED-XRF analysis indicated that Cd was only detectable in necroses of SS5 leaves, while in A4A it was relatively more diffuse. Phytochelatins (PCs) were not detected in SS5, while their concentration was high in both Poli and A4A. The absence of these molecules in SS5 is thought to favour confinement of high accumulations of Cd to necrotic areas and gives SS5 the ability to maintain high photosynthesis and transpiration in remaining parts of the leaf.

Heavy Metal Contamination in Peach Trees Irrigated with Water from a Heavily Polluted Creek

ABSTRACT This study was conducted to characterize the heavy metal contamination in the soils of peach orchards irrigated with water from Nilüfer creek, which is heavily polluted by industrial and municipal wastes. Twenty-one peach orchards with 3 different cultivars in 7 orchards each located along Nilüfer creek were monitored in the experiment. To determine levels of pollution, soils and aboveground parts of the trees were sampled and analyzed for iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), cobalt (Co), nickel (Ni), chromium (Cr), lead (Pb), and cadmium (Cd). Total amounts of Ni and Cr were found to be at the excessive levels in soils. Extractable Ni concentration decreased with increasing pH and CaCO3 content in soils. Leaf metal contents were generally at tolerable levels, but Ni and Pb accumulated to toxic levels in different parts of the fruit (flesh and peel). Except for Fe and Ni, plant concentrations of the metals did not correlate with their total and DTPA-extractable concentrations in the soils. There was no significant difference among the cultivars in accumulation of heavy metals.