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PubMed2002

Twenty-five years of biomonitoring lead in the Frankfurt/Main area.

The present study is an example of the historical monitoring of heavy metals. The specific question it aims to explore is: to what extent has the lead content of selected organisms used for biomonitoring in Frankfurt/Main--one of the cities in Germany most heavily affected by automobile traffic--changed as a result of legislation on leaded gasoline? Data on the lead content of the moss species Bryum argenteum Hedw. from the years 1974, 1975 and 1978 and data on the lead content of the outer bark of the ash species Fraxinus excelsior L. from 1973 served as the basis for the repeated measurements. Remeasurement was successful in 76.5% (i.e. 124 trees at 26 growth sites). The study produced the following results: As was expected, the lead content of the short-term accumulator Bryum argenteum Hedw. was distinctly lowered with a decreasing particulate lead concentration. However, the reduction factor varied greatly between the different growth sites. On the other hand, the lead content measured in the outer bark layers of Fraxinus excelsior L. has risen markedly during the past two decades. Whereas in 1973 nearly all trees examined displayed very low concentrations of lead (< 38 ppm), only 9.5% were still in this category in 1997 and nearly 30% exhibited high or even unacceptable lead concentrations (< 150 ppm-->225 ppm). Various factors have to be taken into account to explain this increase. First of all, bark is a long-term accumulator for heavy metals like lead and its enrichment capacity could have increased as the surface becomes rougher over time. Furthermore, lead is most probably leached out of the bark to a lesser degree now than in the 1970s, owing to the reduced concentration of sulphuric acid in the rain. The dramatic growth of automobile traffic in the Frankfurt/Main area during the period covered by the study undoubtedly plays an important role as well.

Bryopsida↗
PubMed2002

Effects of heavy metals on the nitrogen metabolism of the aquatic moss Fontinalis antipyretica L. ex Hedw. A 15N tracer study.

The assessment of pollution in aquatic systems necessitates an accurate indication of toxicity of heavy metals for organisms and ecosystems. We used the stable nitrogen isotope 15N to estimate the influence of the heavy metals Cd, Pb and Zn on the synthesis of nitrogen-containing fractions in the aquatic moss Fontinalis antipyretica. This method permits conclusions concerning inhibitory effects of these heavy metals on the assimilation of nitrogen and the biosynthesis of amino acids and proteins. The moss was exposed to metal concentrations of 25-500 microM over a period of 5-10 days. 15N abundance of exposed plants was compared with that of control plants. Similar to a loss of vitality determined using a fluorometric assay, a decrease of the 15N abundance in the N fractions of Fontinalis antipyretica was measured in dependence on the metal concentration. Nevertheless, the individual inhibition by the distinct metals was different, so that the following order of toxicity was derived: Cd >> Pb > Zn.

Amino Acids↗
PubMed1997

Gravitropism in tip-growing cells.

Unicellular tip-growing cells are excellent experimental systems in which to study gravitropism because cell extension, gravity sensing and the gravity response are all confined to the apical dome. Thus various approaches can be used to determine the distinct steps of the short gravitropic signal-transduction chain, which lacks a signal-transmission phase between the gravity-sensing cells and the competent responding target cells. Single-cell systems readily allow in-vivo observation of cellular processes during gravistimulation at 1 g, centrifugation, clinostatting and in microgravity, as well as permitting fluorescence labeling. Such diverse studies have revealed fascinating information on the mechanism of gravitropic tip growth, especially on the important role of the cytoskeleton in the positioning of the statoliths and in organizing and adjusting the Spitzenkorper. A hypothesis explaining the negative and positive gravitropism of Chara rhizoids and Chara protonemata has been put forward, which emphasizes the role of the actin cytoskeleton in the process of gravitropic tip-growth. Differences in the gravitropic responses of single-cell systems, however, reflect a diversity of gravitropic mechanisms, and represent an example of parallel evolution.

Bryopsida↗
PubMed2003

Microwave sample-digestion procedure for determination of arsenic in moss samples using electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

Arsenic in moss samples was determined by electrothermal atomic absorption spectrometry (ETAAS) after microwave-assisted sample digestion. Two different sample masses (500 mg and 1000 mg) and three different microwave ovens were used in the digestion. There was a slight difference in the digestion efficiency, as determined by the residual carbon concentrations of 500 mg digested samples, between the microwave ovens. The arsenic results obtained for moss reference samples were, in most cases, satisfactory. However, phosphorus was found to have a reducing influence on the arsenic peak area in the ETAAS determination. According to the results, it was not possible to reduce the phosphorus interference by increasing the amount of Mg(NO(3))(2) in the Pd-Mg chemical modifier. The arsenic results obtained by ETAAS were compared to those obtained by inductively coupled plasma mass spectrometry (ICP-MS).

Arsenic↗
PubMed2007

Use of the diffusive gradients in thin films technique to evaluate (bio)available trace metal concentrations in river water.

Concentrations of Cd, Cu, Cr, Pb, Ni and Zn were monitored in the Svitava River (the Czech Republic) during April and September 2005. Total concentrations and total dissolved concentrations were obtained through regular water sampling, and the diffusive gradients in thin films technique (DGT) were used to gain information on the kinetically labile metal concentrations. Each measured concentration was compared with the corresponding average (bio)available concentration calculated from the mass of metal accumulated by the moss species Fontinalis antipyretica. The concentrations of Cd, Pb, Cr and Zn measured using DGT corresponded well with those obtained after the deployment of Fontinalis antipyretica moss bags in the Svitava River, but the concentrations of Cu and Ni did not. The calculated (bio)available Cu concentration correlated well with the total dissolved concentration of Cu, whereas no correlation was found to exist between the concentrations of Ni.

Bryopsida↗
PubMed2001

Ultrasound-assisted solubilization of trace and minor metals from plant tissue using ethylenediaminetetraacetic acid in alkaline medium.

A simplified and fast sample pretreatment method based on ultrasound-assisted solubilization of metals from plant tissue with ethylenediaminetetraacetic acid in alkaline medium is described. Powdered unknown and certified plant samples (particle size < 50 microns) were slurried in the solubilization medium and subjected to high intensity ultrasonication by a probe ultrasonic processor (20 kHz, 100 W). Metal solubilization can be accomplished within 3 min using a 30% vibrational amplitude and 0.1 M EDTA at pH 10, the supernatant obtained upon centrifugation being used for analysis. The method is applied to several food plants with unknown metal contents and certified plant samples such as CRM GBW07605 tea leaves, BCR CRM 61 aquatic moss and BCR CRM 482 lichen, with good trueness and precision. Intensive treatments with concentrated acids involving total matrix decomposition can be avoided. Metal determination (Ca, Cd, Mg, Mn, Pb and Zn) in the alkaline extracts was carried out by flame and electrothermal atomic absorption spectrometry.

Bryopsida↗
PubMed2000

Comparison of open microwave digestion and digestion by conventional heating for the determination of Cd, Cr, Cu and Pb in algae using transverse heated electrothermal atomic absorption spectrometry.

A comparison between open microwave digestion and digestion by conventional heating was carried out for the determination of Cd, Cr, Cu, and Pb in two algae matrices using transverse heated electrothermal atomic absorption spectrometry (ETAAS). A SRM GBW 08504 cabbage was also analysed. These matrices were digested with HNO3, using a quartz vessel for microwave digestion and PFA vessel for digestion by conventional heating. Cd, Cu and Cr were determined without any modifier, while magnesium nitrate and ammonium phosphate mixed modifier was used for Pb. Results obtained by both the procedures were in good agreement with each other at 95% confidence level, and for SRM GBW 08504 cabbage the values agree well with the certified values. The limits of detection obtained were 0.0004, 0.060, 0.065 and 0.054 mg/kg for Cd, Cr, Cu, and Pb, respectively, using the microwave digestion process. The RSD for Cd was 10-15% and for the other elements 5-10%.

Bryopsida↗
PubMed2000

Analysis of phytochelatins in plant matrices by pre-column derivatization, high-performance liquid chromatography and fluorescence-detection.

A sensitive method for the determination of phytochelatins in plant matrices by pre-column derivatization with monobromobimane (mBrB) and high-performance liquid chromatography (HPLC) on reversed phases and fluorescence-detection has been developed and applied to cucumber sprouts (Cucumis sativus) treated with cadmium and to the water moss Fontinalis antipyretica (Cd in environmentally-relevant concentrations). Whereas phytochelatins were found in the Cd-treated sprouts, no phytochelatins were detected in Fontinalis anitipyretica.

Bryopsida↗
PubMed2002

Divergent intron conservation in the mitochondrial nad2 gene: signatures for the three bryophyte classes (mosses, liverworts, and hornworts) and the lycophytes.

The slow-evolving mitochondrial DNAs of plants have potentially conserved information on the phylogenetic branching of the earliest land plants. We present the nad2 gene structures in hornworts and liverworts and in the presumptive earliest-branching vascular land plant clade, the Lycopodiopsida. Taken together with the recently obtained nad2 data for mosses, each class of bryophytes presents another pattern of angiosperm-type introns conserved in nad2: intron nad2i1 in mosses; intron nad2i3 in liverworts; and both introns, nad2i3 and nad2i4, in hornworts. The lycopods Isoetes and Lycopodium show diverging intron conservation and feature a unique novel intron, termed nad2i3b. Hence, mitochondrial introns in general are positionally stable in the bryophytes and provide significant intraclade phylogenetic information, but the nad2 introns, in particular, cannot resolve the interclade relationships of the bryophyte classes and to the tracheophytes. The necessity for RNA editing to reconstitute conserved codon entities in nad2 is obvious for all clades except the marchantiid liverworts. Finally, we find that particularly small group II introns appear as a general feature of the Isoetes chondriome. Plant mitochondrial peculiarities such as RNA editing frequency, U-to-C type of RNA editing, and small group II introns appear to be genus-specific rather than gene-specific features.

Amino Acid Sequence↗
PubMed2002

A novel gene family in moss (Physcomitrella patens) shows sequence homology and a phylogenetic relationship with the TIR-NBS class of plant disease resistance genes.

Plant disease resistance (R) genes encode proteins in which several motifs of the nucleotide-binding region (NBS) are highly conserved. Using degenerate primers designed according to the kinase 1 (P-loop) and hydrophobic (HD) motifs of the R gene NBS domains, homologous sequences were cloned from moss (Physcomitrella patens; phylum Bryophyta) representing an ancient nonvascular plant. A novel gene family (PpC) with at least eight homologous members was found. Expression of five members was detected. The level of expression was dependent on the developmental stage of moss, being higher in the gametophyte tissue than in the protonema tissue. The PpCs contained the conserved motifs characteristic of the NBS regions of R genes, and a kinase domain was found upstream from the NBS region. Phylogenetic analysis using the deduced NBS amino acid sequences of the PpCs and the plant genes available in databanks indicated that the PpCs show the closest relationship with the TIR-NBS class of R genes. No significant similarity to plant genes other than R genes was observed. These findings shed novel light on the evolutionary history of the R gene families, suggesting that the NBS region characteristic of the TIR-NBS class of R-like genes evolved prior to the evolutionary differentiation of vascular and nonvascular plants.

Amino Acid Sequence↗
PubMed2005

Differences in concentration of heavy metals between native and transplanted Plagiothecium denticulatum: a case study of soils contaminated by oil well exudates in South East Poland.

For a period of 60 days, the terrestrial moss Plagiothecium denticulatum was transplanted from a clean control site to a soil contaminated with crude oil exudates (Krosno, South East Poland). Native P. denticulatum growing on this contaminated soil was collected during the same period. Concentrations of the metals Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn as well as the macroelements N, P, K, Ca, Mg, and S were determined in P. denticulatum and in soils from the contaminated and control sites. Contaminated soil was the main contributor of Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn to native and transplanted P. denticulatum. Other sources of contamination apart from the soil existed for Cd and Cu. Transplanted P. denticulatum accumulated significantly more Al, Cr, Cu, Ni, Pb, and Zn, and native P. denticulatum accumulated significantly more N, P, K, and Ca. Higher levels of N, P, K, and Ca in native P. denticulatum indicates a possible mechanism to prevent the loss of these elements as observed in the transplanted P. denticulatum.

Bryopsida↗
PubMed2005

Definition and number of subsamples for using mosses as biomonitors of airborne trace elements.

We collected 50 subsamples of the moss Scleropodium purum from each of three sampling sites and determined the concentrations of As, Cd, Cu, K, Hg, Ni, Pb, Se, and Zn in each subsample. We then calculated the number of subsamples required to determine significant differences in the mean concentrations of two sampling sites. We found that to differentiate between an uncontaminated sampling site and another, slightly contaminated site, 30 subsamples are required from each. On the basis of these results and because, to date, there are no studies that justify the application of the previously proposed recommendations, studies of local variability in other areas, and under different conditions, with other contaminants and moss species must be undertaken. For posterior comparison of data on variability as well as application of the recommendations associated with such results, the general use of a single definition of a subsample is required. We propose the following definition of a subsample: "1 g dry weight (approx.), collected within a 25-cm radius of a node, selected at random from a 1 x 1-m sampling grid placed in a sampling site."

Air Pollution↗
PubMed2000

The effect of pH on the kinetics of intra- and extracellular uptake of Al in Fontinalis antipyretica: changes in the cellular contents of K, Mg, and Ca.

The effect of acidity on the accumulation of Al in the aquatic bryophyte Fontinalis antipyretica was studied. The main interest of this study was in characterizing the relationship between the two parameters, as Al is typically mobilized in acidic environments, where it becomes extremely toxic. With this aim, a series of laboratory experiments were carried out where samples of F. antipyretica were held in tanks of water with different concentrations of Al (0.1-3 mg L(-1)) and levels of acidity (pH 3-5. 8). The incubation time varied between 1 and 24 h. In general, the greatest accumulations of both intra- and extracellular Al were found at a pH of 4.4. With the results obtained, the kinetics of both intra- and extracellular Al uptake was characterized, and models constructed for different combinations of Al and acidity. The study was completed by examining the relationship between the pH of the holding water and bioaccumulation of Al and the variation in concentration of cations essential to plant life, which are also indicators of changes in cellular physiology (K, Mg, Ca). In general, losses of these elements were found at intra- and extracellular locations, especially at high pH.

Aluminum↗
PubMed2001

Evaluation of contamination, by different elements, in terrestrial mosses.

Evaluation was made of the degree to which samples of terrestrial mosses (Scleropodium purum and Hypnum cupressiforme) collected in Galicia (NW Spain) were contaminated by different elements. The concentrations of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, S, Se, and Zn in the mosses were determined, then the contamination factors were calculated by dividing each value by the corresponding background level of that element. To assess contamination using contamination factors (CFs), a scale was established that allowed categorization of sampling sites for each element determined. The proposed scale comprises six categories, ranging from CF values of less than 1 (no contamination) to values of greater than 27 (extreme contamination). Finally, all available information was brought together and summarized in a contamination index. This index has the advantage that it takes into account the toxicity of the elements and that can be used with an already existing scale of classification.

Air Pollution↗
PubMed1997

Bioindication of heavy metals in soil by liverworts.

Studies were made of the accumulation of the heavy metals Ba, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Sr, V, and Zn and the macroelements N, P, K, Ca, and Mg in liverworts Conocephalum conicum, Marchantia polymorphia, and Pellia epiphylla collected from 57 microhabitats in Poland (Lower Silesia, Tatry Mts., and Puszcza Augustowska forest) and one microhabitat in the Czech Republic (Moravsky Kras). Ecological differentiation of Conocephalum conicum, Marchantia polymorpha and Pellia epiphylla populations is closely correlated with the soil chemistry. The evidence for this assumption are the significant positive correlations between concentrations of elements in soil and in the examined liverworts. In particular, correlations between contents of chromium and cobalt in soil and in Conocephalum conicum and between nickel, chromium, copper, and barium in soil and in Pellia epiphylla prove that these plants can be useful in monitoring of contamination of soil with elements mentioned above. Concentrations of cobalt in almost all the examined liverworts surpass the average background values of this element established for terrestrial bryophytes what proves that these plants tolerate increased accumulated amounts of this element and may therefore act as bioindicator for this heavy metal. Cationic equilibrium of Conocephalum conicum, Marchantia polymorpha and Pellia epiphylla examined according to Czarnowski (1977) pointed to the existence of some disturbances in ionic balance of these plants caused probably by elevated concentrations of microelements (especially iron, cobalt, lead, and copper) in their tissues.

Biological Assay↗
PubMed1998

Influence of water hardness on accumulation and elimination of cadmium in two aquatic mosses under laboratory conditions.

This study investigated the effect of water hardness on the accumulation and elimination of cadmium (Cd) by two aquatic mosses, Fontinalis dalecarlica and Platyhypnidium riparioides, under laboratory conditions. The two mosses were exposed to nominal Cd concentrations of 0, 0.8, 2, and 10 microg . L-1, which includes the concentration range generally found in nature. The influence of three levels of water hardness (very soft: 11.7 mg . L-1; soft: 44.2 mg . L-1; and hard water: 92.3 mg . L-1 as CaCO3) was measured while maintaining the alkalinity and pH constant during the 28-day exposure. The Cd accumulation by the aquatic mosses was rapid, showing the potential of accumulation and the sensitivity of this biomonitor. Even if the actual Cd concentration in the water was low (concentration <0.15 microg . L-1 to 6.82 microg . L-1 of Cd), the uptake of Cd was very fast and mostly linear. This study was conducted in water hardness comparable to that found in the Canadian shield (hardness was <100 mg . L-1 as CaCO3). When the actual Cd concentration in the water was as high as 6.82 microg . L-1, the uptake of Cd was mostly linear and the steady state condition was not reach. Accumulation rates of Cd were significantly different when the mosses were in very soft (11.7 mg . L-1) as compared to hard water (92.3 mg . L-1 as CaCO3). The elimination of Cd followed a very slow process for the two species studied. The elimination rates of Cd from the mosses were not influenced by water hardness.

Bryopsida↗