Arundo donax as a potential biomonitor of trace element contamination in water and sediment

The traces elements absorption, accumulation and translocation ability of Phragmites australis

In this study, the wastewater analyses of Oued K'sob for one year showed a spatiotemporal diminution of zinc content seasonally, it rest light than copper. But Zinc and copper a threat to the environment of the region. The wastewater analyses of Oued K'sob water for one year showed a spatiotemporal diminution of zinc content seasonally, with a minimum and maximum range of 249 ± 219 µg/l and 2382 ± 3426 µg/l obtained in autumn and summer for the zinc and 75 ± 24 µg/l and 433 ± 310 µg/l obtained in winter and spring at the first and fifth station for the copper. These concentrations of zinc and copper a threat to the environment of the region. Like a solution for this problem, the absorption, accumulation and translocation abilities of Phragmites australis were determined toward iron (Fe), copper (Cu), zinc (Zn) and lead (Pb). In the soils contaminated by different concentrations (100, 200 and 500 mg/L), the absorption, accumulation and transport ability of elements were evaluated via the Bio-concentration (BCF), Bioaccumulation (BF) and Translocation (TF) factors. A proportional increase between the BCF, BFs, TFs and the irrigation concentrations, where BCFs of all metallic elements exceed 1 and the Zn BCF, BFs and TFL are the highest and exceed 1 relative to the other elements which remain lower than 1, which has a low accumulation. Therefore, according to the BCFs obtained and which exceed 1, we can consider this plant as a hyper-accumulator of Zn, Fe, Cu and Pb. Extraction of fatty and organic acids followed by HPLC confirmed the oxalic, citric, malic, succinic, fumaric, formic, acetic, propionic, and butyric acid presence, which are responsible for the transport of the metal from roots to leaves. In the light of these results, we can therefore propose Phragmites australis species as an alternative and natural solution to reduce the high concentrations of zinc and copper in the Oued k'sob (region of Bordj Bou Arreridj, Algeria).

Emergent (branched bur-reed-Sparganium erectum L.) and submergent (river water-crowfoot-Ranunculus fluitans Wimm., 1841) aquatic plants as metal biosorbents under varying water pH conditions in laboratory conditions

A laboratory experiment was performed to find out the potential bioaccumulation of metals (Al, Cu, Cd, Ni, Pb, Fe, Mn) in aquatic plants acting as natural biosorbents in the environment depending on the variation of water pH. Two plants were selected for the study: branched bur-reed-Sparganium erectum L., as a representative of emergent plants; and river water-crowfoot-Ranunculus fluitans Wimm., 1841, as a representative of submergent plants. The bioaccumulation of metals in plants relative to water (BCFW) was determined, and the metal pollution index (MPI) was calculated. The metal content in water and plants before the experiment was arranged in the following series of increasing values: Cd = Ni < Cu < Pb < Mn < Al < Fe (water) and Cd < Cu < Ni < Pb < Al < Fe < Mn (in both plants). The lowest concentration of cadmium was found in water both at the end and beginning of the experiment. In turn, aluminum level increased, and its concentration was the highest in both acidic and alkaline water. This suggests that aluminum is definitely more available to the organisms living in it under such conditions, and in higher concentrations may be a limiting factor for them. Bioaccumulation of metals (BCFW) in neutral and alkaline environments was higher in branched bur-reed, and in acidic conditions in river water-crowfoot. This may provide a basis for using specific plant species to selectively accumulate metals depending on the range of water pH. This is also supported by the MPI values, which indicate that they have a very high and often the highest impact on metal pollution levels. The observed variability of metals bioaccumulation against the condition of hydromacrophytes makes it possible to consider these plants as biosorbents used in constructed biological treatment plants, which, depending on the species placed there, can selectively absorb particular trace elements. The plants used in the experiment are common hydromacrophytes of Europe, so they can be used in the construction of artificial wetlands across the continent. The apparent diversity of metal accumulation in relation to hydromacrophytes indicates that this type of site can be inhabited by specific species, which can significantly improve the purification of natural or anthropogenic water reservoirs, i.e., those that are intended to perform a filtering function.

Uptake of Cu, Hg, and As in wild vegetation, associated to surface water in the Copiapó valley, before the 2015 alluvium

In an annual monitoring in the Copiapó valley, the concentration of Cu, Hg, and As in sediments was related to environmental transfer processes, these elements also being present in surface water. The goal was to evaluate the uptake of the mentioned elements in wild plants of the Copiapó Valley, to determine if these species could be indicator plants to prevent environmental risks in local agriculture. From the same monitoring, the uptake of the elements was determined in wild plants growing near the irrigation channels; canopy of Tessaria absinthioides, Equisetum giganteum, Arundo donax, Melilotus indicus, Cortaderia rudiscula, and Sarcocornia neei was analyzed for the same elements. These plants were able to uptake Cu, Hg and As in concentration between 19 and 4674.5 times the environmental limits allowed for edible plants. This result shows that crop plants can also capture contaminants elements due to the frequency of irrigation. These plants can be used as indicators for the diagnosis of capture of the pollutants elements by plants and to prevent environmental hazards to human health in agricultural products from the Copiapó valley.

Possibility of Metal Accumulation in Reed Canary Grass (Phalaris arundinacea L.) in the Aquatic Environment of South-Western Polish Rivers

A four-year research study was conducted on aquatic plants (reed canary grass) growing in the beds of three rivers and their tributaries in Lower Silesia, Poland. Metal contents (Cu, Cd, Ni, Pb, Zn, Fe, Mn) were determined in plant samples, metal accumulation in water (BCFw) and sediment (BCFB), Metal Pollution Index (MPI) and Enrichment Factor (EF) were calculated. The highest contents of copper, lead, nickel and cadmium were found in reed canary grass sampled from the Nysa Szalona River. The highest values were recorded for zinc in the Bystrzyca River, and for iron and manganese in the Strzegomka River. The series of metals were as follows: Nysa Szalona and Strzegomka: Cd < Ni < Pb < Cu < Zn < Mn < Fe, Bystrzyca: Cd < Ni < Cu < Pb < Zn < Mn < Fe. Throughout the study period, the lowest values of metals in plants were recorded in 2015 and 2018, and the highest in 2017. The general picture of MPI in aquatic plants is arranged in the series Bystrzyca < Strzegomka < Nysa Szalona. These values classify the studied material at a high level of pollution in all rivers. In the comparison of the two extreme sites, i.e., source−mouth, higher values were found at the mouth of the reservoir, which suggests that metals move with the water current and accumulate more with the direction of the river flow, which is most likely a consequence of the influence of the catchment area as the source of metals. The series of EF enrichment factor values were as follows: Bystrzyca—Ni < Cd < Fe < Cu < Zn < Mn < Pb, Nysa Szalona—Ni < Fe < Zn < Cd < Mn < Cu < Pb, Strzegomka—Ni < Cd < Fe < Zn < Cu < Pb < Mn. For all the samples studied, the values found in spring were much higher than in autumn, which indicates the great importance for research in that area. The levels of copper and iron were within the range of moderate values, lead and manganese reached very high and exceptionally high values, and the remaining metals were within the values described as significant. Bioaccumulation of metals determined relative to bottom sediments was highest in 2017 and lowest in 2018, while bioaccumulation relative to water was highest in 2018 and lowest in 2016. The four-year study found that the metal content in reed canary grass was mostly within the range of mean values presented in the literature from moderately polluted areas. Also, no significant deviation was found from levels that have been recorded for the same rivers for more than two decades.

Global leaf and root transcriptome in response to cadmium reveals tolerance mechanisms in Arundo donax L

The expected increase of sustainable energy demand has shifted the attention towards bioenergy crops. Due to their know tolerance against abiotic stress and relatively low nutritional requirements, they have been proposed as election crops to be cultivated in marginal lands without disturbing the part of lands employed for agricultural purposes. Arundo donax L. is a promising bioenergy crop whose behaviour under water and salt stress has been recently studied at transcriptomic levels. As the anthropogenic activities produced in the last years a worrying increase of cadmium contamination worldwide, the aim of our work was to decipher the global transcriptomic response of A. donax leaf and root in the perspective of its cultivation in contaminated soil. In our study, RNA-seq libraries yielded a total of 416 million clean reads and 10.4 Gb per sample. De novo assembly of clean reads resulted in 378,521 transcripts and 126,668 unigenes with N50 length of 1812 bp and 1555 bp, respectively. Differential gene expression analysis revealed 5,303 deregulated transcripts (3,206 up- and 2,097 down regulated) specifically observed in the Cd-treated roots compared to Cd-treated leaves. Among them, we identified genes related to “Protein biosynthesis”, “Phytohormone action”, “Nutrient uptake”, “Cell wall organisation”, “Polyamine metabolism”, “Reactive oxygen species metabolism” and “Ion membrane transport”. Globally, our results indicate that ethylene biosynthesis and the downstream signal cascade are strongly induced by cadmium stress. In accordance to ethylene role in the interaction with the ROS generation and scavenging machinery, the transcription of several genes (NADPH oxidase 1, superoxide dismutase, ascorbate peroxidase, different glutathione S-transferases and catalase) devoted to cope the oxidative stress is strongly activated. Several small signal peptides belonging to ROTUNDIFOLIA, CLAVATA3, and C-TERMINALLY ENCODED PEPTIDE 1 (CEP) are also among the up-regulated genes in Cd-treated roots functioning as messenger molecules from root to shoot in order to communicate the stressful status to the upper part of the plants. Finally, the main finding of our work is that genes involved in cell wall remodelling and lignification are decisively up-regulated in giant reed roots. This probably represents a mechanism to avoid cadmium uptake which strongly supports the possibility to cultivate giant cane in contaminated soils in the perspective to reserve agricultural soil for food and feed crops.

Aluminum Bioaccumulation in Reed Canary Grass (Phalaris arundinacea L.) from Rivers in Southwestern Poland

This study aimed to determine aluminum levels in reed canary grass Phalaris arundinacea L.) in rivers in southwestern Poland—Bystrzyca, Strzegomka, and Nysa Szalona, together with their tributaries. The samples were collected in spring and autumn 2015−2018. The highest amounts of aluminum were recorded in the Nysa Szalona, and the lowest in the Bystrzyca. During the four-year cycle of studies, the highest values were recorded in the last year, and the lowest in the first year. The highest amounts of aluminum were found in all three rivers in the lowland tributaries. In the main rivers, higher amounts of aluminum were found at the mouth of the Nysa Szalona and Strzegomka reservoirs, while the opposite situation was found for the Bystrzyca. Higher aluminum contents were recorded in autumn than in spring, and the values of BCFW (aluminum bioaccumulation factor in relation to water) and BCFB (aluminum bioaccumulation factor in relation to bottom sediments) coefficients were also higher. The MPI (metal pollution index) was arranged in a series: Bystrzyca < Strzegomka < Nysa Szalona, while the degree of pollution was high for Bystrzyca and very high for the other two rivers. The variability in Al levels may be attributed to pollution level in the catchments, but also to successive modernization works carried out in the beds of the main rivers and their tributaries. All these works were carried out in a variable way and often covered only a fragment of the riverbed; therefore, the consequences of activity may have been visible in the catchment but not necessarily in the same vegetation cycles.

Aluminum in Bottom Sediments of the Lower Silesian Rivers Supplying Dam Reservoirs vs. Selected Chemical Parameters

The study was carried out on sediments collected from three rivers: Nysa Szalona, Strzegomka and Bystrzyca flowing in southwestern Poland. The content of Al in sediments and in bottom water was determined in relation to chemical conditions. The study was carried out in a four-year cycle, during spring and autumn. The aim of the study was to determine the level and accumulation of aluminum in sediments of rivers supplying dam reservoirs storing water for consumption. The sediments studied were mineral in nature, with neutral pH and moderate sulfate content. The level of Al and heavy metals in the sediments was the highest in the Nysa Szalona River and the lowest in the Strzegomka River, which was also evident in the concentration factor (CF). In terms of season, higher Al contents were recorded in sediments in autumn than in spring, which was also reflected in the concentration factor (CF). Along the course of the river, a gradual decrease in Al levels was observed in successive tributaries in the Nysa Szalona and Strzegomka Rivers, while there was no apparent regularity for the Bystrzyca. Against this background, a comparison of extreme sites below the springs and at the reservoir outlet shows that values were higher in the Nysa Szalona below the springs, and lower in the Strzegomka and Bystrzyca below the reservoir outlet. The general picture of Al and heavy metal loading of the studied sediments shows the lowest loading for the Strzegomka, only the enrichment factor (EF) was the lowest for the Nysa Szalona: metal pollution index (MPI)-S < B < NS, contamination factor (C_f)-S < B < NS, degree of contamination (DC)-S < NS < B, EF-NS < B < S, geoaccumulation index (I_geo)-S < B < NS, CF-S < NS < B. There was no effect of catchment size and river length on Al levels in sediments.

Comparison of the single and combined effects of arsenic and antimony on growth and physiology of giant reed (Arundo donax L.)

Fast-growing plant, giant reed (Arundo donax L.) has been gaining a lot of popularity in the phytoremediation of metal-polluted soils. However, information regarding the physiological background of tolerance and accumulation capacity of A. donax with respect to antimony (Sb), arsenic (As), and their co-contamination are very limited. Rooted stem cuttings were grown for 5 months in hydroponics exposed to Sb (10 mg L^-1), As (10 mg L^-1), and their combined toxicity (Sb 5 mg L^-1 + As 5 mg L^-1) wherein treatment without As/Sb served as control. Effect of these treatments on key photosynthetic parameters (rate of net photosynthesis, effective quantum yield of photosystem II, chlorophyll fluorescence, and photosynthetic pigments), phytoextraction ability of metalloids, nutrient uptake, root growth, and lignification were analyzed. Arsenic-containing treatments severely affected root morphology of A. donax compared to Sb/control and plants exposed to As showed intensive lignification already in young apical part of the root in the present study. Shoot concentration was found to be 11.35±0.75 Sb mg kg^-1 and 8.97±0.52 As mg kg^-1 compared to root concentration of 1028.3±19.1 Sb mg kg^-1 and 705.3±69.9 As mg kg^-1 in the treatments of Sb and As. Even though Sb and As were translocated to the shoots in relatively small amount, both metalloids significantly decreased the shoot and root growth of A. donax and negatively affected the photosynthetic parameters. Moreover, co-contamination of Sb and As proved to be severely toxic to growth and physiology of A. donax even though the magnitudes of the metalloids used were lower than those of Sb/As alone treatments. In conclusion, Sb and As caused a marked reduction in growth and physiological characteristics of A. donax, opposing its use in phytoremediation of highly contaminated soils. Tolerance capacity of plants to simultaneous presence of As and Sb in the environment is crucial for the successful implementation of phytoremediation since the co-contamination by As and Sb might reduce the efficiency of phytoremediation when using this fast-growing and high biomass-producing plant species.

Arundo donax L.: An overview on its traditional and ethnomedicinal importance, phytochemistry, and pharmacological aspects

Arundo donax L. (Giant reed) is a grass species belong to Poaceae family with a myriad of uses such as traditional and ethnomedicinal values, bioenergy, and socio-economic importance. The plant is used in conventional medicine to treat various disorders related to skin, gastrointestinal, skeletal, menstrual problems, respiratory and urinary diseases. The present review summarises the scattered information on socio-economic importance, ethnomedicinal uses, phytochemistry and pharmacological aspects of this plant. We conducted a rigorous literature survey using databases such as Scopus, Science Direct, Web of Science, Google Scholar, and PubMed entering keywords like A. donax, Giant reed, and Spanish reed, etc. Phytochemical investigations have identified several alkaloids, terpenoids, sterols, phenolics, and lignin derivatives. The isolated phytoconstituents are reported to exhibit multiple pharmacological activities such as anti-bacterial, anti-oxidant, anti-proliferative, anti-spasmolytic, and also used to treat helminthic infestations in cattle. However, the scientific validity of traditional practices to cure various diseases has not been correctly evaluated yet. Therefore, it is recommended to further investigate the plant for clinical trials to unleash its therapeutic importance towards chemical characterisation for drug discovery and development in the pharmacological field.

Bioaugmented Phytoremediation of Metal-Contaminated Soils and Sediments by Hemp and Giant Reed

We assessed the effects of EDTA and selected plant growth-promoting rhizobacteria (PGPR) on the phytoremediation of soils and sediments historically contaminated by Cr, Ni, and Cu. A total of 42 bacterial strains resistant to these heavy metals (HMs) were isolated and screened for PGP traits and metal bioaccumulation, and two Enterobacter spp. strains were finally selected. Phytoremediation pot experiments of 2 months duration were carried out with hemp (Cannabis sativa L.) and giant reed (Arundo donax L.) grown on soils and sediments respectively, comparing in both cases the effects of bioaugmentation with a single PGPR and EDTA addition on plant and root growth, plant HM uptake, HM leaching, as well as the changes that occurred in soil microbial communities (structure, biomass, and activity). Good removal percentages on a dry mass basis of Cr (0.4%), Ni (0.6%), and Cu (0.9%) were observed in giant reed while negligible values (<100‰) in hemp. In giant reed, HMs accumulated differentially in plant (rhizomes > > roots > leaves > stems) with largest quantities in rhizomes (Cr 0.6, Ni 3.7, and Cu 2.2 g plant^–1). EDTA increased Ni and Cu translocation to aerial parts in both crops, despite that in sediments high HM concentrations in leachates were measured. PGPR did not impact fine root diameter distribution of both crops compared with control while EDTA negatively affected root diameter class length (DCL) distribution. Under HM contamination, giant reed roots become shorter (from 5.2 to 2.3 mm cm^–3) while hemp roots become shorter and thickened from 0.13 to 0.26 mm. A consistent indirect effect of HM levels on the soil microbiome (diversity and activity) mediated by plant response (root DCL distribution) was observed. Multivariate analysis of bacterial diversity and activity revealed not only significant effects of plant and soil type (rhizosphere vs. bulk) but also a clear and similar differentiation of communities between control, EDTA, and PGPR treatments. We propose root DCL distribution as a key plant trait to understand detrimental effect of HMs on microbial communities. Positive evidence of the soil-microbe-plant interactions occurring when bioaugmentation with PGPR is associated with deep-rooting perennial crops makes this combination preferable over the one with chelating agents. Such knowledge might help to yield better bioaugmented bioremediation results in contaminated sites.

Assessing Arundo donax L. in vitro-tolerance for phytoremediation purposes

Phytoremediation using high production crops could be an alternative for the recovery of metals polluted soils. In this sense, the Arundo donax L. energy crop has shown tolerance to moderate concentrations of heavy metals. The objective of this work was to test the tolerance of micropropagated plants of Arundo donax to increasing concentrations of cadmium, chromium, cooper, nickel and lead, in an in vitro culture medium. Biomass production and concentration of heavy metal in shoots and roots were analyzed. Results showed that heavy metals were accumulated mostly in subterranean organs. The increase in heavy metal concentration was dose dependent and not always follows a linear relationship. Arundo donax showed a broad tolerance to cadmium (0.5 mM), chromium (0.2 mM), cooper (2 mM), nickel (0.5 mM) and lead (1 mM). In relation to cooper, Arundo donax showed a hyperaccumulative potential. These results suggest the potential use of Arundo donax in the phytomanagement of polluted soils although further studies should be carried out using polluted soils.

Accumulation of heavy metals in phytoliths from reeds growing on mining environments in Southern Europe

In Southern Europe, soil contamination by heavy metals (HM) due to mining and industrial activities is a long-known problem. Yet, despite soils being widely contaminated through decades, some plants are still able to grow. Some of these plants, like giant reed (Arundo donax) or common reed (Phragmites australis) are capable of accumulating substantial amount of HM. These reeds also contain small silica structures in their shoots, called phytoliths. However, the role of phytoliths in reducing stress caused by these HM remains unknown. The aim of this work is then to determine if phytoliths represent a preferential structure for the bioacccumulation of HM in plants. Therefore, plants from mining-contaminated sites in Spain and France were sampled and HM concentrations in total plant shoots were compared to those in phytoliths for eight metal(oid)s: As, Cd, Cu, Mn, Pb, Sb, Sn and Zn. Results show that Arundo donax and Phragmites australis tend to accumulate Cd, Sb and Sn but limit the uptake of As, Cu, Mn, Pb and Zn in plant shoots despite that the concentration of these HM in soil is quite high. Therefore, reeds appear as tolerant to high metal concentrations in soils, and phytoliths are identified as preferential structures for encapsulation of As, Cu, Mn, Pb and Zn, while Cd, Sb and Sn were mainly found to be accumulated in organic tissues rather than in phytoliths.

Ecological types and bioindicator macrophyte species of pollution of riparian vegetation of Oued Lârbaa in Taza City of Morocco

The object of our study is devoted to the Spermatophyta of the wetlands of Oued Lârbaa, the main river of the city of Taza, Morocco, and which is under strong anthropic pressure. Our work involved a floristic inventory, to define ecological types and groups of dominant plants in relation to seasonal factors and types of pollution, explaining the meaning of their presence. For this purpose, floristic sampling was carried out along the Oued during the dry periods (2017 and 2018) and the wet period (2018). A total of 66 plant species belonging to 54 genera and 30 families were identified, including 44 species during the wet period (2018) and 27 species during the dry periods (2017 and 2018). This difference is due to the favorable conditions for vegetation development during the period of precipitation and to the increase in pollution rates during the dry season. The inventoried flora shows the dominance of 10 ecological types characterized by the following plants: Cynodon dactylon, Arundo donax, Olea europaea, and Tamarix gallica (common between the two periods); Dittrichia viscosa, Visnaga daucoides, Typha angustifolia, and Ricinus communis (during the dry periods of 2017 and 2018); and Juncus maritimus and Populus nigra (during the wet period of 2018). The ecological types identified in this work decrease from the dry season to the rainy season, while specific richness increases. These dominant plants are all considered as bioindicators of the presence of heavy metals.

Evaluation of the Efficiency of Arundo donax L. Leaves as Biomonitors for Atmospheric Element Concentrations in an Urban and Industrial Area of Central Italy

Washed and unwashed Arundo donax L. (A. donax) leaves were analyzed for elements, and results were compared with element concentrations detected in river water and particulate matter (PM) Samples were collected along a river in an urban and industrial hot spot of Central Italy, where element concentrations show relevant spatial gradients both in air and river water. The aim of this study is to identify the role of the two environmental matrices on leaves composition. Element concentrations of washed and unwashed leaves were compared to differentiate between the superficial deposition and the uptake into leaf tissues of elements. Water-soluble and -insoluble element concentrations were measured in PM10 samples collected on membrane filters by using innovative high spatial resolution samplers. The comparison among leaf and atmospheric concentrations of PM10 elements showed a similar trend for Ni, Mo, Cr, Ti, and Fe, which are reliable tracers of the PM10 contribution by steel plant and vehicular traffic. Soluble species appeared to be mainly bounded into leaf tissues, while insoluble species were deposited on their surface. On the other hand, element concentrations detected in washed A. donax leaves were poorly correlated with those measured in river water samples. The obtained results proved that A. donax leaves can be used as reliable biomonitors for the evaluation of the atmospheric concentrations of some PM10 elemental components.

Evolution and functional differentiation of recently diverged phytochelatin synthase genes from Arundo donax L

Phytochelatin synthases (PCSs) play pivotal roles in the detoxification of heavy metals and metalloids in plants; however, little information on the evolution of recently duplicated PCS genes in plant species is available. Here we characterize the evolution and functional differentiation of three PCS genes from the giant reed (Arundo donax L.), a biomass/bioenergy crop with remarkable resistance to cadmium and other heavy metals. Phylogenetic reconstruction with PCS genes from fully sequenced monocotyledonous genomes indicated that the three A. donax PCSs, namely AdPCS1-3, form a monophyletic clade. The AdPCS1-3 genes were expressed at low levels in many A. donax organs and displayed different levels of cadmium-responsive expression in roots. Overexpression of AdPCS1-3 in Arabidopsis thaliana and yeast reproduced the phenotype of functional PCS genes. Mass spectrometry analyses confirmed that AdPCS1-3 are all functional enzymes, but with significant differences in the amount of the phytochelatins synthesized. Moreover, heterogeneous evolutionary rates characterized the AdPCS1-3 genes, indicative of relaxed natural selection. These results highlight the elevated functional differentiation of A. donax PCS genes from both a transcriptional and an enzymatic point of view, providing evidence of the high evolvability of PCS genes and of plant responsiveness to heavy metal stress.

Gene expression and biochemical response of giant reed under Ni and Cu stress

Giant reed (Arundo donax) has proved to be effective in detoxification, accumulation and tolerance of toxic metals. The present study explored the stress response of giant reed against Cu and Ni stress. The effect of metal stress was studied on dry weight, chlorophyll pigments antioxidant enzymes production and selected genes expression. The accumulation of heavy metals increased in a concentration-dependent manner and depicted toxicity symptoms in leaves beyond 75 mg/L of Cu or Ni. Oxidative stress was evident in giant reed under highest exposure of Ni and Cu which increased antioxidants activities (SOD, POD and CAT). It was observed that metal transport and detoxification were possible due to the expression of glutathione reductase, Natural Resistance-Associated Macrophage Protein (NRAMP) and Yellow Stripe-Like (YSL) genes. These insights into the genetic basis of a successful remediating plant species will be useful in understanding heavy metals tolerance in giant reed.

Trace elements removal ability and antioxidant activity of Phragmites australis (from Algeria)

In this study, roots, stems and leaves of the worldwide distributed macrophyte Phragmites australis (common reed) were tested as potential removal and biomonitors of trace elements contamination in sediment. In particular, the concentrations (100, 200, and 500 mg/kg) of the following elements were analyzed: Zn, Cu, Pb, and Fe. Results showed that the amount of concentrations in plant tissues is significantly (p ≤ 0.01) dependent on the kind of organ and element. Trace element concentrations decreased according to the pattern of Fe^a (Roots^a > Stems^b > Leaves^b) > Zn^b (Root^a > Leaves^b > Stems^c) > Cu^c (Roots^a > Leaves^b > Stems^c) > Pb^c (Roots^a > Stems^b > Leaves^c), as well as the roots acted as the main centers of bioaccumulation for all elements studied, and stems as the transit organs for translocation from roots to leaves. The major mechanisms employed by the plant were probably phytostabilization on the basis of the calculated Biological Concentration Factor (BCF - metal concentration ratio of plant root to soil); and Translocation Factor (TF - metal concentration ratio of plants roots to above ground part). Finally, due to the low scavenger effect of the radical DPPH, we excluded the hypothesis of the use of antioxidant mechanism in the tolerance of metals.

Selenate tolerance and selenium hyperaccumulation in the monocot giant reed (Arundo donax), a biomass crop plant with phytoremediation potential

The response of giant reed (Arundo donax L.) to selenium (Se), added as selenate, was studied. The development, stress response, uptake, translocation, and accumulation of Se were documented in three giant reed ecotypes STM (Hungary), BL (USA), and ESP (Spain), representing different climatic zones. Plantlets regenerated from sterile tissue cultures were grown under greenhouse conditions in sand supplemented with 0, 2.5, 5, and 10 mg Se kg^-1 added as sodium selenate. Total Se content was measured in different plant parts using hydride generation atomic fluorescence spectroscopy. All plants developed normally in the 0-5.0 mg Se kg^-1 concentration range regardless of ecotype, but no growth occurred at 10.0 mg Se kg^-1. There were no signs of chlorosis or necrosis, and the photosynthetic machinery was not affected as evidenced by no marked differences in the structure of thylakoid membranes. There was no change in the maximum quantum yield of photosystem II (F_v/F_m ratio) in the three ecotypes under Se stress, except for a significant negative effect in the ESP ecotype in the 5.0 mg Se kg^-1 treatment. Glutathione peroxidase (GPx) activity increased as the Se concentration increased in the growth medium. GPx activity was higher in the shoot system than the root system in all Se treatments. All ecotypes showed great capacity of take up, translocate and accumulate selenium in their stem and leaf. Relative Se accumulation is best described as leaf ˃˃ stem ˃ root. The ESP ecotype accumulated 1783 μg g^-1 in leaf, followed by BL with 1769 μg g^-1, and STM with 1606 μg g^-1 in the 5.0 mg Se kg^-1 treatment. All ecotypes showed high values of translocation and bioaccumulation factors, particularly the ESP ecotype (10.1 and 689, respectively, at the highest tolerated Se supplementation level). Based on these findings, Arundo donax has been identified as the first monocot hyperaccumulator of selenium, because Se concentration in the leaves of all three ecotypes, and also in the stem of the ESP ecotype, is higher than 0.1% (dry weight basis) under the conditions tested. Tolerance up to 5.0 mg Se kg^-1 and the Se hyperaccumulation capacity make giant reed a promising tool for Se phytoremediation.

Physiology and selected genes expression under cadmium stress in Arundo donax L

The effects of cadmium stress (0, 25, 50, 75, and 100 mg/L) on morpho-physiological features and selected genes (carotenoid hydroxilase, amidase, GR, bHLH, NRAMP and YSL) expression were demonstrated in Arundo donax L. The plants were assessed for Cd uptake and its effects on chlorophyll and antioxidants after 30 days of exposure. The expression of genes conferring metal tolerance was evaluated after 10 days of Cd exposure. The results showed a maximum Cd uptake in roots (872 mg/kg) followed by stem (734 mg/kg) and leaves (298 mg/kg) at highest supplied Cd concentration. The Cd uptake reduced dry weight, Chla, Chlb, and total Chl contents of giant reed. The SOD, CAT, POD activities and MDA content increased at the maximum Cd concentration over control. The highest genes expression for carotenoid hydroxylase, glutathione reductase and amidase was observed in plants exposed to 100 mg/L. However, differential bHLH gene expression and slightly increased gene expression of NRAMP was noted for different Cd treatments. Amidase expressed under Cd stress which is pioneer report in A. donax. These results provided insights into the mechanisms of A. donax tolerance and survival under Cd Stress.

Seagrass Halophila stipulacea: Capacity of accumulation and biomonitoring of trace elements

This study aimed to shed further light on the capacity of the seagrass Halophila stipulacea to accumulate and biomonitor the elements As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn, present in water and sediments. Results showed that the organs of H. stipulacea accumulate different levels of trace elements, whose concentrations decrease mainly in the order of roots>rhizomes>leaves. The seagrass H. stipulacea showed levels of trace elements similar to those found in other Mediterranean seagrasses, e.g. Posidonia oceanica and Cymodocea nodosa. This study showed that H. stipulacea could act as a promising bioindicator of several elements, present in sediments, including As, Cd, Cu, Mn, Ni and Zn.

Comparative assessment of trace element accumulation and bioindication in seagrasses Posidonia oceanica, Cymodocea nodosa and Halophila stipulacea

Accumulation and bioindication of trace elements were compared in three seagrasses growing in the Mediterranean Sea: Posidonia oceanica, Cymodocea nodosa and Halophila stipulacea. The levels of the elements As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn were investigated in water, sediments, and roots, rhizomes and leaves of seagrasses. Results showed that seagrasses can accumulate comparable levels of trace elements, but P. oceanica and C. nodosa showed higher mean values of element accumulation. Moreover, P. oceanica and C. nodosa may accumulate high element concentrations in their leaves, whereas in H. stipulacea restricted with the bulk of trace elements in roots and rhizomes. Seagrasses reflected to a different degree the levels of several trace elements in sediments, especially P. oceanica and C. nodosa, whose use as bioindicators is recommended. The future step for an effective use of seagrasses as bioindicators of marine pollution is to set up biomonitoring networks on a large scale.

Trace elements in Mediterranean seagrasses and macroalgae. A review

This review investigates the current state of knowledge on the levels of the main essential and non-essential trace elements in Mediterranean vascular plants and macroalgae. The research focuses also on the so far known effects of high element concentrations on these marine organisms. The possible use of plants and algae as bioindicators of marine pollution is discussed as well. The presence of trace elements is overall well known in all five Mediterranean vascular plants, whereas current studies investigated element concentrations in only c. 5.0% of all native Mediterranean macroalgae. Although seagrasses and macroalgae can generally accumulate and tolerate high concentrations of trace elements, phytotoxic levels are still not clearly identified for both groups of organisms. Moreover, although the high accumulation of trace elements in seagrasses and macroalgae is considered as a significant risk for the associated food webs, the real magnitude of this risk has not been adequately investigated yet. The current research provides enough scientific evidence that seagrasses and macroalgae may act as effective bioindicators, especially the former for trace elements in sediments, and the latter in seawater. The combined use of seagrasses and macroalgae as bioindicators still lacks validated protocols, whose application should be strongly encouraged to biomonitor exhaustively the presence of trace elements in the abiotic and biotic components of coastal ecosystems.

Comparative analysis of trace element accumulation in seagrasses Posidonia oceanica and Cymodocea nodosa: Biomonitoring applications and legislative issues

This study aimed to compare the bioaccumulation patterns and translocation of trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) from the environment in the seagrasses Posidonia oceanica and Cymodocea nodosa. Results showed that P. oceanica has a higher capacity of accumulation. P. oceanica and C. nodosa accumulate mainly in roots and leaves, the main organs acting as potential bioindicators. No significant correlation was found between water and both seagrasses. In turn, P. oceanica and C. nodosa were correlated, to a different extent, with As, Cd, Cu, Ni and Zn in sediments. This study showed also that current European regulations do not provide an exhaustive set of legal concentration limits of trace elements in marine water and sediments. Seagrasses P. oceanica and C. nodosa can act as effective bioindicators of trace elements only if quality limits are set for the most toxic elements present in marine ecosystems.

Chemical elements in Mediterranean macroalgae. A review

This review analyzes the state of knowledge on the capacity of Mediterranean macroalgae to accumulate, tolerate and biomonitor macro- and micro-elements present in seawater and sediments. The results show that the investigated macroalgal species amount to c. 5.0% of all Mediterranean native Rhodophyta, Chlorophyta and Ochrophyta. The most commonly analyzed elements in algae were Pb, Cd, Zn and Cu, whereas very few studies were available for macroelements such as Ca and K. Uptake mechanisms and the factors influencing accumulation are overall well known, but the available studies are restricted to a limited number of chemical elements and algal species. This review also shows that macroalgae can accumulate and tolerate high concentrations of chemical elements, and can act as effective bioindicators of marine pollution. Phytotoxic limits for algal species are not clearly identified by the available studies and require further investigation. Future research should focus on the development of protocols for long-term biomonitoring programmes through the use of macroalgae. Future studies also need to investigate the biomagnification of toxic trace elements in macroalgae-based food webs.

Trace elements in Mediterranean seagrasses: Accumulation, tolerance and biomonitoring. A review

This study investigated the state of the art on trace elements in Mediterranean seagrasses, and their close environment (seawater and sediment). The analyzed species were Posidonia oceanica, Cymodocea nodosa, Halophila stipulacea, Zostera marina and Zostera noltei. All these species showed high tolerance to pollution and high capacity of accumulation of trace elements. Seagrasses also showed similar patterns of accumulation: the highest concentrations of As, Hg and Pb were found in the roots, whereas those of Cd, Cr, Cu, Mn, Ni and Zn were found in the leaves. Phytotoxic levels in seagrasses are unknown for most trace elements. The accumulation of trace elements in seagrasses is widely recognized as a risk to the whole food web, but the real magnitude of this risk is still uncertain. Seagrasses are known to act as trace element bioindicators, but this potential is still poorly valued for the creation of biomonitoring networks.

Comparative analysis of element concentrations and translocation in three wetland congener plants: Typha domingensis, Typha latifolia and Typha angustifolia

This study analyzed the concentrations and distributions of Al, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn in three different cattail species growing spontaneously in a natural wetland subject to municipal wastewater and metal contamination. The cattail species included Typha domingensis, T. latifolia and T. angustifolia. Results showed that all Typha species have similar element concentrations in roots, rhizomes and leaves, and similar element mobility from sediments to roots and from roots to leaves. This study corroborated three patterns of Typha species growing in metal contaminated environments: high tolerance to toxic conditions, bulk element concentrations in roots, and restricted element translocation from roots to leaves. This study showed that three different Typha species respond similarly to metal inputs under the same polluting field conditions. Given their similar metal content and similar biomass size, our results suggest that T. domingensis, T. latifolia and T. angustifolia may have comparable capacity of phytoremediation. High element uptake and large biomass make Typha species some of the best species for phytoremediation of metal contaminated environments.

Evaluation of the phytoremediation potential of Arundo donax L. for nickel-contaminated soil

This study investigates the accumulation and distribution of nickel in Arundo donax L. parts to assess the potential use of this plant in phytoremediation of Ni-contaminated soils. The effect of ethylene diamine tetra-acetic acid (EDTA) and nutrient solution containing NPK on the plant was proped. A 35-day pot experiment was performed in the laboratory and the pots were irrigated with Ni-contaminated solution combined or not with EDTA and NPK. The growth of plants was evaluated at the end of the experiment. The accumulation of Ni was analyzed by atomic absorption spectroscopy (AAS). The obtained results indicate that the plant was able to survive with high Ni content. The growth and the concentrations of Ni in the plant tissues were less affected. In the absence of the amendments, Ni was accumulated in the stems and leaves. However, the addition of NPK significantly reduced Ni concentration in the stems and leaves. The application of EDTA enhanced Ni uptake in roots. The translocation factor (TF) was greater than 1, which categorizes A. donax L. as a great candidate for Ni phytoextraction. A. donax L. is suitable for phytoremediation of Ni. This investigation contributes to the studies on the potential of phytoremediation technologies in Algeria.

Trace element compartmentation in the seagrass Posidonia oceanica and biomonitoring applications

This study investigated the trace element bioaccumulation capacity of the Mediterranean seagrass Posidonia oceanica, and its suitability as a bioindicator of contamination in water and sediments. Results showed that P. oceanica leaves accumulate higher concentrations of Ni and Zn. Since P. oceanica regenerates its leaves periodically, the higher concentrations in aerial organs may suggest a "removal" strategy according to which P. oceanica accumulates greater concentrations of trace elements in its temporary organs. In turn, P. oceanica seems to adopt an exclusion strategy for toxic non-essential elements (As, Cr, Pb). Results showed also that P. oceanica organs are correlated with As, Cd, Cu, Ni, and Zn concentrations in sediments. No significant relationship was found between P. oceanica and water. This study showed that P. oceanica may adopt different tolerance strategies compared to mainland-rooted macrophytes, and its possible use as a bioindicator of trace elements in sediments should be considered.

A comparison of trace metal bioaccumulation and distribution in Typha latifolia and Phragmites australis: implication for phytoremediation

The aims of the present investigation were to reveal various trace metal accumulation abilities of two common helophytes Typha latifolia and Phragmites australis and to investigate their potential use in the phytoremediation of environmental metal pollution. The concentrations of Fe, Mn, Zn, Cu, Cd, Pb and Ni were determined in roots, rhizomes, stems and leaves of both species studied as well as in corresponding water and bottom sediments from 19 sites selected within seven lakes in western Poland (Leszczyńskie Lakeland). The principal component and classification analysis showed that P. australis leaves were correlated with the highest Mn, Fe and Cd concentrations, but T. latifolia leaves with the highest Pb, Zn and Cu concentrations. However, roots of the P. australis were correlated with the highest Mn, Fe and Cu concentrations, while T. latifolia roots had the highest Pb, Zn and Cd concentrations. Despite the differences in trace metal accumulation ability between the species studied, Fe, Cu, Zn, Pb and Ni concentrations in the P. australis and T. latifolia exhibited the following accumulation scheme: roots > rhizomes > leaves > stems, while Mn decreased in the following order: root > leaf > rhizome > stem. The high values of bioaccumulation factors and low values of translocation factors for Zn, Mn, Pb and Cu indicated the potential application of T. latifolia and P. australis in the phytostabilisation of contaminated aquatic ecosystems. Due to high biomass of aboveground organs of both species, the amount of trace metals stored in these organs during the vegetation period was considerably high, despite of the small trace metals transport.

Typha latifolia (broadleaf cattail) as bioindicator of different types of pollution in aquatic ecosystems-application of self-organizing feature map (neural network)

The contents of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in leaves of Typha latifolia (broadleaf cattail), water and bottom sediment from 72 study sites designated in different regions of Poland were determined using atomic absorption spectrometry. The aim of the study was to evaluate potential use of T. latifolia in biomonitoring of trace metal pollution. The self-organizing feature map (SOFM) identifying groups of sampling sites with similar concentrations of metals in cattail leaves was able to classify study sites according to similar use and potential sources of pollution. Maps prepared for water and bottom sediment showed corresponding groups of sampling sites which suggested similarity of samples features. High concentrations of Fe, Cd, Cu, and Ni were characteristic for industrial areas. Elevated Pb concentrations were noted in regions with intensive vehicle traffic, while high Mn and Zn contents were reported in leaves from the agricultural area. Manganese content in leaves of T. latifolia was high irrespectively of the concentrations in bottom sediments and water so cattail can be considered the leaf accumulator of Mn. Once trained, SOFMs can be applied in ecological investigations and could form a future basis for recognizing the type of pollution in aquatic environments by analyzing the concentrations of elements in T. latifolia.

Copper Uptake Efficiency and Its Distribution Within Bioenergy Grass Giant Reed

To evaluate copper uptake and its toxicity on bioenergy grass giant reed (Arundo donax L.), experiments were carried out using two epigenetic clonal lines - American (BL) and Hungarian (20SZ) ecotypes - grown on elevated Cu concentrations up to 26.8 mg L(-1). Neither ecotype showed any noticeable foliar symptoms of Cu toxicity at concentrations tested up to 10 mg L(-1). Dry mass of plants of both ecotypes significantly increased at the highest Cu treatment compared to control. Although the BL ecotype had greater capacity to uptake Cu than 20SZ, the dry mass and shoot length of BL was higher than that of 20SZ. Values of bioconcentration and transportation factors were higher in the BL than in the 20SZ ecotype. Almost 45 % of total Cu content within the whole plant was found in the plant root of both ecotypes. This demonstrated both ecotypes can be utilized for Cu phytoremediation alongside with significant biomass production.

Macro- and microelement distribution in organs of Glyceria maxima and biomonitoring applications

The content of nutrients (N, P, K, Ca and Mg) and of trace metals (Fe, Cu, Mn, Zn, Pb, Cd, Co and Ni) in water, bottom sediments and various organs of Glyceria maxima from 19 study sites selected in the Jeziorka River was determined. In general, the concentrations of nutrients recorded in the plant material decreased in the following order: leaf>root>rhizome>stem, while the concentrations of the trace elements showed the following accumulation scheme: root>rhizome>leaf>stem. The bioaccumulation and transfer factors for nutrients were significantly higher than for trace metals. G. maxima from agricultural fields was characterised by the highest P and K concentrations in leaves, and plants from forested land contained high Zn and Ni amounts. However, the manna grass from small localities showed high accumulation of Ca, Mg and Mn. Positive significant correlations between Fe, Cu, Zn, Cd, Co and Ni concentrations in water or sediments and their concentrations in plant indicate that G. maxima may be employed as a biomonitor of trace element contamination. Moreover, a high degree of similarity was noted between self-organizing feature map (SOFM)-grouped sites of comparable quantities of elements in the water and sediments and sites where G. maxima had a corresponding content of the same elements in its leaves. Therefore, SOFM could be recommended in analysing ecological conditions of the environment from the perspective of nutrients and trace element content in different plant species and their surroundings.

Phytoaccumulation potentials of two biotechnologically propagated ecotypes of Arundo donax in copper-contaminated synthetic wastewater

An in vitro experiment was carried out to evaluate the phytoremediation potentials of two somatic embryo-derived ecotypes of Arundo donax-BL (American ecotype) and 20SZ (Hungarian ecotype)-of copper from synthetic wastewater. The two ecotypes were grown under sterile conditions in tubes containing a nutrient solution supplied with increasing doses of Cu (0, 1, 2, 3, 5, 10, and 26.8 mg L(-1)) for 6 weeks. The translocation and bioaccumulation factors and removal rate were estimated. In general, increasing Cu concentration in nutrient solution slightly decreased root, stem and leaf biomass without toxicity symptoms up to 26.8 mg L(-1). Moreover, both ecotypes showed high Cu removal efficiency from aqueous solution. However, Cu removal rate ranged between 96.6 to 98.8% for BL ecotype and 97 to 100% for 20SZ ecotype. Data illustrated that both BL and 20SZ ecotypes may be employed to treat Cu-contaminated water bodies up to 26.8 mg L(-1).

Phytoaccumulation potentials of two biotechnologically propagated ecotypes of Arundo donax in copper-contaminated synthetic wastewater

An in vitro experiment was carried out to evaluate the phytoremediation potentials of two somatic embryo-derived ecotypes of Arundo donax-BL (American ecotype) and 20SZ (Hungarian ecotype)-of copper from synthetic wastewater. The two ecotypes were grown under sterile conditions in tubes containing a nutrient solution supplied with increasing doses of Cu (0, 1, 2, 3, 5, 10, and 26.8 mg L(-1)) for 6 weeks. The translocation and bioaccumulation factors and removal rate were estimated. In general, increasing Cu concentration in nutrient solution slightly decreased root, stem and leaf biomass without toxicity symptoms up to 26.8 mg L(-1). Moreover, both ecotypes showed high Cu removal efficiency from aqueous solution. However, Cu removal rate ranged between 96.6 to 98.8% for BL ecotype and 97 to 100% for 20SZ ecotype. Data illustrated that both BL and 20SZ ecotypes may be employed to treat Cu-contaminated water bodies up to 26.8 mg L(-1).

Arundo donax L., a candidate for phytomanaging water and soils contaminated by trace elements and producing plant-based feedstock. A review

Plants and associated microorganisms are used to remediate anthropogenic metal(loid) contamination of water, soils and sediments. This review focuses on the potential of Arundo donax L. (Giant reed) for alleviating risks due to soils, water, and sediments contaminated by trace elements (TE), with emphasis on its advantages and limits over macrophytes and perennial grasses used for bioenergy and plant-based feedstock. Arundo donax is relevant to phytomanage TE-contaminated matrices, notably in its native area, as it possesses characteristics of large biomass production even under nutrient and abiotic stresses, fast growth rate, TE tolerance and accumulation mainly in below ground plant parts. Cultivating A. donax on contaminated lands and in constructed wetlands can contribute to increase land availability and limit the food vs. plant-based feedstock controversy. To gain more tools for decision-taking and sustainable management,further researches on A. donax should focus on: interactions between roots, TE exposure, and rhizosphere and endophytic microorganisms; biomass response to (a)biotic factors; sustainable agricultural practices on marginal and contaminated land; integration into local, efficient, energy and biomass conversion chains with concern to biomass quality and production; Life-Cycle Assessment including contaminant behavior, as well as environmental, agricultural and socio-economic benefits and drawbacks.

Comparative performance of trace element bioaccumulation and biomonitoring in the plant species Typha domingensis, Phragmites australis and Arundo donax

Toxic levels of trace elements in the environment have been reported worldwide over the last few decades, and their increasing concentrations are of the utmost concern because of the adverse effects on human life and ecosystems. Several plant species are able to accumulate trace elements, and may be used for monitoring and remediation of polluted sites. This study compared the capacity of trace element bioaccumulation in three wetland plants distributed worldwide: Typha domingensis, Phragmites australis and Arundo donax. The aims were to identify which species show better potential for removal and monitoring of these elements: Al, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn. Results showed that all species may be used as biomonitors of trace element contamination in sediment, but only P. australis and A. donax showed also a correlation with water. Overall, T. domingensis and P. australis showed a greater capacity of bioaccumulation as well as a greater efficiency of element removal than A. donax. In particular, T. domingensis and P. australis may be used for Hg phytostabilization, the former acted also as a hyperaccumulator for Hg phytoextraction and as a promising species for As phytostabilization. In contaminated wetlands, the presence of T. domingensis and P. australis may increase the general retention of trace elements, thus, their introduction is recommended for possible actions of phytoremediation and biomonitoring.

Matching metal pollution with bioavailability, bioaccumulation and biomarkers response in fish (Centropomus parallelus) resident in neotropical estuaries

Two neotropical estuaries affected by different anthropogenic factors were studied. We report levels of metals and metalloids in water and sediment as well as their influence on genetic, biochemical and morphological biomarkers in the native fish Centropomus parallelus. Biomarkers reflected the fish health status. Multivariate statistics indicated both spatial and temporal changes in both water and sediment, which are linked to the elemental composition and health status of inhabitant fish, showing the biggest influence of surface water, followed by sediments and interstitial water. Bioaccumulation in fish muscle was useful to identify elements that were below detection limits in water, pointing out the risk of consuming fish exceeding allowance limits for some elements (As and Hg in this case). Multivariate statistics, including physical, chemical and biological issues, presents a suitable tool, integrating data from different origin allocated in the same estuary, which could be useful for future studies on estuarine systems.