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At least 19 recordsLinked to original sources

PubMed2006

Pteris umbrosa R. Br. as an arsenic hyperaccumulator: accumulation, partitioning and comparison with the established As hyperaccumulator Pteris vittata.

The capacity of the Australian native fern Pteris umbrosa to function as an arsenic (As) hyperaccumulator (shoot:soil As concentration >1) was examined by growing plants under glasshouse conditions in an inert medium supplemented with As. Arsenic preferentially accumulated in the fronds, a trait of a hyperaccumulator. The As concentration of fronds decreased with age, being particularly high in the croziers and low in the senesced fronds. Below ground, rhizomes accumulated more As than adventitious roots. Uptake from a range of solution concentrations followed Michaelis Menten kinetics up to a soil solution As concentration of 400mgl(-1). The K(m) for As uptake by roots suggested the operation of a low-affinity carrier. The predicted Nernst membrane potential indicated that uptake was against the electrochemical gradient of As. At 600mgl(-1), the rate of As uptake increased and phytotoxic effects were indicated by a significant decline in biomass. Arsenic uptake and translocation in P. umbrosa and Pteris vittata were similar at low exposure to As. At higher exposure, As uptake and translocation by P. vittata increased more than in P. umbrosa. The growth rate of both ferns was similar, whereas the biomass distribution was not, with P. vittata having a much larger root mass. This suggests that As uptake by P. umbrosa roots was very efficient and may be improved by stimulating root growth to enhance its potential.

Arsenicals↗

PubMed2005

Arsenic speciation, and arsenic and phosphate distribution in arsenic hyperaccumulator Pteris vittata L. and non-hyperaccumulator Pteris ensiformis L.

This study examined the roles of arsenic translocation and reduction, and P distribution in arsenic detoxification of Pteris vittata L. (Chinese Brake fern), an arsenic hyperaccumulator and Pteris ensiformis L. (Slender Brake fern), a non-arsenic hyperaccumulator. After growing in 20% Hoagland solution containing 0, 133 or 267 microM of sodium arsenate for 1, 5 or 10 d, the plants were separated into fronds, rhizomes, and roots. They were analyzed for biomass, and concentrations of arsenate (AsV), arsenite (AsIII) and phosphorus. Arsenic in the fronds of P. vittata was up to 20 times greater than that of P. ensiformis, yet showing no toxicity symptoms as did in P. ensiformis. While arsenic was concentrated primarily in the fronds of P. vittata as arsenite it was mainly concentrated in the roots of P. ensiformis as arsenate. Arsenic reduction in the plants took longer than 1-d. P. vittata maintained greater P in the roots while P. ensiformis in the fronds. The high arsenic tolerance of the hyperaccumulator P. vittata may be attributed to its ability to effectively reduce arsenate to arsenite in the fronds, translocate arsenic from the roots to fronds, and maintain a greater ratio of P/As in the roots.

Arsenates↗

PubMed2005

Comparison of root absorption, translocation and tolerance of arsenic in the hyperaccumulator Pteris vittata and the nonhyperaccumulator Pteris tremula.

* Several fern species can hyperaccumulate arsenic, although the mechanisms are not fully understood. Here we investigate the roles of root absorption, translocation and tolerance in As hyperaccumulation by comparing the hyperaccumulator Pteris vittata and the nonhyperaccumulator Pteris tremula. * The two species were grown in a pot experiment with 0-500 mg As kg-1 added as arsenate, and in a short-term (8 h) uptake experiment with 5 microM arsenate under phosphorus-sufficient conditions. * In the pot experiment, P. vittata accumulated up to 2500 mg As kg-1 frond d. wt and suffered no phytotoxicity. P. tremula accumulated<100 mg As kg-1 frond d. wt and suffered severe phytotoxicity with additions of >or=25 mg As kg-1. In the short-term uptake experiment, P. vittata had a 2.2-fold higher rate of arsenate uptake than P. tremula, and distributed more As taken up to the fronds (76%) than did P. tremula (9%). * Our results show that enhanced root uptake, efficient root-to-shoot translocation, and a much elevated tolerance through internal detoxification all contribute to As hyperaccumulation in P. vittata.

Absorption↗

PubMed2006

Uptake and accumulation of arsenic by 11 Pteris taxa from southern China.

A field survey was conducted at a deserted arsenic (As) mine in Guangxi Province, China to explore new potential As hyperaccumulators. In addition, young plants of 11 Pteris taxa were grown in glasshouse conditions for 12 weeks on As-amended soils with 0, 50 and 200 mg As kg(-1). Results of the field survey showed that the fern Pteris fauriei accumulated over 1000 mg As kg(-1) in its fronds. Of the 11 Pteris taxa, Pteris aspericaulis, Pteris cretica var. nervosa, P. fauriei, Pteris multifida, P. multifida f. serrulata, and Pteris oshimensis were all found to hyperaccumulate As in addition to P. cretica 'Albo-Lineata' and Pteris vittata (already reported as As hyperaccumulators). However, Pteris ensiformis, Pteris semipinnata and Pteris setuloso-costulata showed no evidence of As hyperaccumulation. Results also revealed a constitutive property of As hyperaccumulation in different populations of P. cretica var. nervosa, P. multifida, P. oshimensis and P. vittata.

Agriculture↗

PubMed2004

Mechanisms of arsenic hyperaccumulation in Pteris species: root As influx and translocation.

Several species of fern from the Pteris genus are able to accumulate extremely high concentrations of arsenic (As) in the fronds. We have conducted short-term unidirectional As influx and translocation experiments with 73As-radiolabeled arsenate, and found that the concentration-dependent influx of arsenate into roots was significantly larger in two of these As-hyperaccumulating species, Pteris vittata (L.) and Pteris cretica cv. Mayii (L.), than in Nephrolepis exaltata (L.), a non-accumulating fern. The arsenate influx could be described by Michaelis-Menten kinetics and the kinetic parameter Km was found to be lower in the Pteris species, indicating higher affinity of the transport protein for arsenate. Quantitative analysis of kinetic parameters showed that phosphate inhibited arsenate influx in a directly competitive manner, consistent with the hypothesis that arsenate enters plant roots on a phosphate-transport protein. The significantly augmented translocation of arsenic to the shoots that was seen in these As hyperaccumulator species is proposed to be due to a combination of the increased root influx and also decreased sequestration of As in the roots, as a larger fraction of As could be extracted from roots of the Pteris species than from roots of N. exaltata. This leaves a larger pool of mobile As available for translocation to the shoot, probably predominantly as arsenite.

Arsenic↗

PubMed2002

[Analysis of the diterpenoids in the extract of Pteris semipinnata L by HPLC-APCI-MS].

AIM: To establish an accurate and reliable method for quantitative analysis of the diterpenoids in Pteris semipinnata L. METHODS: A quadruple mass spectrometer coupled with atmospheric pressure chemical ionization interface was employed as a detector for HPLC. As to MS detector, selective ion monitoring (SIM) scan mode was used. For ent-11 alpha-hydroxy-15-oxo-kaur-16-en-19-olic acid (5F) and ent-11 alpha-hydroxy-15-oxo-kaur-16(R) methyl-19-olic acid (4F), the majority of the diterpenoids in Pteris semipinnata L, the [M-H]-1 ion were observed, and the [M-H2O-H]-1 ion could be observed from the collision-induced dissociation spectua. [M-H]-1 was selected as the SIM ion in quantification, the mobile phase and the MS conditions were optimized. The mobile phase of HPLC was 30% CH3CN-70% 2 mmol.L-1 NH4Ac, analytical column was Diamonsil ODS (4.6 mm x 150 mm), flow rate 1.0 mL.min-1, inject volume 5 microL. The area of ion flow peak were used for quantitative determination. As an example of its application, this method was used to determine the content of 5F as an antitumor diterpenoid in Pteris semipinnata L. RESULTS: The content of 5F accounted 1.18 mg.g-1 in Pteris semipinnata L sample. For 5F, RT is about 4.3 min, the standard curve showed good linearity over the range of 0.05-2.5 micrograms, gamma = 0.9998 (n = 5); the recovery was 97.8% (n = 5); the limit of detection was 0.4 ng (inject 5 microL). CONCLUSION: This method is highly sensitive, accurate and fast, which can be applied to study the antitumor drug of diterpenoids in Pteris semipinnata L and to establish the raw herb standard.

Antineoplastic Agents, Phytogenic↗

PubMed2005

[Effects of 5F from Pteri semipinnata on the expression of ETS-1 mRNA and VEGF protein of highly metastatic ovarian carcinoma HO-8910PM cells].

OBJECTIVE: To study the effect of 5F from Pteri semipinnata L. on the expression of ETS-1 mRNA and VEGF protein, and to investigate the antitumor mechanisms of 5F from Pteri semipinnata L. METHODS: RT-PCR assay was used to assess the expression level of ETS-1 mRNA. The expression level of VEGF protein was assessed by Western blot analysis. RESULTS: The expression level of of VEGF protein obviously decreased in HO-8910PM cells treated with 25 to approximately 100 micromol/L 5F for 24 hours. 5F significantly down-regulated the expression of ETS-1 mRNA. CONCLUSION: The antitumor activity of 5F from Pteri semipinnata L is involved in the expression of ETS-1 mRNA and VEGF protein.

Antineoplastic Agents, Phytogenic↗

PubMed2005

[Study on the effect and its mechanisms of 5F from Pteri semipinnata L. on the cell cycle of highly metastatic ovarian carcinoma HO-8910PM cells].

OBJECTIVE: To study the effect and its possible mechanism of 5F from Pteri semipinnata L on the cell cycle of human highly metastatic ovarian carcinoma HO-8910PM cells. METHODS: MTT assay was used to examine the effect of 5F on proliferation of HO-8910PM cells after 24 hours treatment; The cell cycle was assessed by flow cytometry (FCM); The expression level of NF-kappaB (p65) FAK and the level of phosphorylated FAK were assessed by Western blot analysis. RESULTS: 5F from Pteris semipinnata L. could inhibit the proliferation of HO-8910PM cell and block the cell cycle at G2/M phase. The expression level of NF-kappaB (P65) protein decreased obviously in HO-8910PM cells treated with 25 - 100 micromol/L 5F for 24 hours, and the effect appeared in a dose-dependent manner. 5F up-regulated significantly the expression of FAK, down-regulated the level of phosphorylated FAK. CONCLUSION: The effect on cell cycle of 5F from Pteri semipinnata L is involved in the expression of NF-kappaF(p65), FAK and the level of phosphorylated FAK.

Antineoplastic Agents, Phytogenic↗

PubMed2005

[Investigation on the chromatogram of diterpenoids in Pteris semipinnata by HPLC-APCI-MS].

To identify and compare the main peaks of HPLC-APCI-MS FP of the diterpenoids in Pteris semipinnata collected from different region and time, a quadrupole mass spectrometer coupled with atmospheric pressure chemical ionization interface was employed as a detector for HPLC to establish total ion chromatography. HPLC retention time and MS spectrum were used to identify comprehensively. 4F, 5F and 6F were identified from the chromatography comparing with their standards. The saturated state of 6F and glycoside of 4F and 5F were inferred. The content of 5F in samples collected from region of Guangzhou or in Nov. and Dec. were comparatively higher. This method is highly effective and fast,which can be applied to research and develop for diterpenoids in Pteris semipinnata L as new antitumor drug resource.

Antineoplastic Agents, Phytogenic↗

PubMed2005

[As-hyperaccumulation of Pteris vittata L. as influenced by as concentrations in soils of contaminated fields].

As soil arsenic concentration might have great effect on arsenic accumulation of hyperaccumulator Pteris vittata L. , three sample areas with different As pollution level in the soils are investigated in Chenzhou, Hunan Province, where Pteris vittata L. grows broadly. Great variation of As concentrations is found to be not only among different samples in the same sampling areas but also between rhizosphere and bulk soil of P. vittata L. So it is suggested that rhizosphere soil should be sampled to study the effect of soil contamination on plant accumulation. The As concentration in frond of P. vittata L. increased dramatically at lower As level but decreased slowly when As concentration higher than 1 000 mg/kg. Arsenic translocation factors of P. vittata L. were greater than 1 in all samples in this study, whereas As concentration in shoots in lower As contaminated soil and bioaccumulation factors in higher As contaminated soil are fail to meet the definition of As hyperaccumulator.

Arsenic↗

PubMed2005

Role of trichome of Pteris vittata L. in arsenic hyperaccumulation.

Environmental scanning electron microscope (ESEM) fitted with an energy dispersive X-ray microanalyzer (EDX) was used to investigate the surface micromorphology and arsenic (As) micro-distribution in Chinese brake (Pteris vittata L.). It was found that amounts of trichome, which possessed multicellular structure with the average length of 160 microm and with an average diameter of 28 microm, existed in the frond of P. vittata, and the density of trichome on the pinnate axial surface was higher than that on the petiole. Visible X-ray peak of As was recorded in the epidermal cell and trichome. The relative weight of As in the pinnate trichome, which contained the highest concentration of As among all tissues of the plant, was 2.4 and 3.9 times as much as that in the epidermal and mesophyllous cells, respectively. The As concentrations in the basal and stalk cells of the same trichome were higher than that in its cap cell. This is the first time to report that the trichome of P. vittata plays an important role in arsenic hyperaccumulation. The finding from the present study implies that much attention should be paid to the role of the trichome in understanding the hyperaccumulation and detoxicity of As in the hyperaccumulator and improving the ability of As accumulation.

Arsenic↗

PubMed2004

Influence of the arbuscular mycorrhizal fungus Glomus mosseae on uptake of arsenate by the As hyperaccumulator fern Pteris vittata L.

We report for the first time some effects of colonization by an arbuscular mycorrhizal (AM) fungus (Glomus mosseae) on the biomass and arsenate uptake of an As hyperaccumulator, Pteris vittata. Two arsenic levels (0 and 300 mg As kg(-1)) were applied to an already contaminated soil in pots with two compartments for plant and hyphal growth in a glasshouse experiment. Arsenic application had little or no effect on mycorrhizal colonization, which was about 50% of root length. Mycorrhizal colonization increased frond dry matter yield, lowered the root/frond weight ratio, and decreased frond As concentration by 33-38%. Nevertheless, transfer of As to fronds showed a 43% increase with mycorrhizal colonization at the higher soil As level. Frond As concentrations reached about 1.6 g kg(-1) (dry matter basis) in non-mycorrhizal plants in the As-amended soil. Mycorrhizal colonization elevated root P concentration at both soil As levels and mycorrhizal plants had higher P/As ratios in both fronds and roots than did non-mycorrhizal controls.

Arsenates↗

PubMed2005

Molecular cloning and characterization of a phytochelatin synthase gene, PvPCS1, from Pteris vittata L.

Pteris vittata L. is a staggeringly efficient arsenic hyperaccumulator that has been shown to be capable of accumulating up to 23,000 microg arsenic g(-1), and thus represents a species that may fully exploit the adaptive potential of plants to toxic metals. However, the molecular mechanisms of adaptation to toxic metal tolerance and hyperaccumulation remain unknown, and P. vittata genes related to metal detoxification have not yet been identified. Here, we report the isolation of a full-length cDNA sequence encoding a phytochelatin synthase (PCS) from P. vittata. The cDNA, designated PvPCS1, predicts a protein of 512 amino acids with a molecular weight of 56.9 kDa. Homology analysis of the PvPCS1 nucleotide sequence revealed that it has low identity with most known plant PCS genes except AyPCS1, and the homology is largely confined to two highly conserved regions near the 5'-end, where the similarity is as high as 85-95%. The amino acid sequence of PvPCS1 contains two Cys-Cys motifs and 12 single Cys, only 4 of which (Cys-56, Cys-90/91, and Cys-109) in the N-terminal half of the protein are conserved in other known PCS polypeptides. When expressed in Saccharomyces cerevisae, PvPCS1 mediated increased Cd tolerance. Cloning of the PCS gene from an arsenic hyperaccumulator may provide information that will help further our understanding of the genetic basis underlying toxic metal tolerance and hyperaccumulation.

Aminoacyltransferases↗

PubMed2006

Arsenic resistance in Pteris vittata L.: identification of a cytosolic triosephosphate isomerase based on cDNA expression cloning in Escherichia coli.

Arsenic hyperaccumulator Pteris vittata L. (Chinese brake fern) grows well in arsenic-contaminated media, with an extraordinary ability to tolerate high levels of arsenic. An expression cloning strategy was employed to identify cDNAs for the genes involved in arsenic resistance in P. vittata. Excised plasmids from the cDNA library of P. vittata fronds were introduced into Escherichia coli XL-1 Blue and plated on medium containing 4 mM of arsenate, a common form of arsenic in the environment. The deduced amino acid sequence of an arsenate-resistant clone, PV4-8, had cDNA highly homologous to plant cytosolic triosephosphate isomerases (cTPI). Cell-free extracts of PV4-8 had 3-fold higher level of triosephosphate isomerase (TPI) specific activities than that found in E. coli XL-1 Blue and had a 42 kD fusion protein immunoreactive to polyclonal antibodies raised against recombinant Solanum chacoense cTPI. The PV4-8 cDNA complemented a TPI-deficient E. coli mutant. PV4-8 expression improved arsenate resistance in E. coli WC3110, a strain deficient in arsenate reductase but not in AW3110 deficient for the whole ars operon. This is consistent with the hypothesis that PV4-8 TPI increased arsenate resistance in E. coli by directly or indirectly functioning as an arsenate reductase. When E. coli tpi gene was expressed in the same vector, bacterial arsenate resistance was not altered, indicating that arsenate tolerance was specific to P. vittata TPI. Paradoxically, P. vittata TPI activity was not more resistant to inhibition by arsenate in vitro than its bacterial counterpart suggesting that arsenate resistance of conventional TPI reaction was not the basis for the cellular arsenate resistance. P. vittata TPI activity was inhibited by incubation with reduced glutathione while bacterial TPI was unaffected. Consistent with cTPI's role in arsenate reduction, bacterial cells expressing fern TPI had significantly greater per cent of cellular arsenic as arsenite compared to cells expressing E. coli TPI. Excised frond tissue infiltrated with arsenate reduced arsenate significantly more under light than dark. This research highlights a novel role for P. vittata cTPI in arsenate reduction.

Amino Acid Sequence↗

PubMed2005

Effect of arsenic on chloroplast ultrastructure and calcium distribution in arsenic hyperaccumulator Pteris vittata L.

This study investigated the impacts of arsenic (As) on the chloroplast ultrastructure and calcium (Ca) distribution in Chinese brake (Pteris vittata L.) mainly by histochemical methods, with an emphasis on the possible function of Ca in As detoxification and accumulation in P. vittata. P. vittata was grown in an artificially contaminated soil added with different concentrations of Na(2)HAsO(4) (0, 100, 300 and 800 mg kg(-1) As dry soil) for 24 weeks in a greenhouse. The addition of As did not affect the chloroplast ultrastructure of young pinna, meanwhile most of the membrane systems of chloroplasts in mature pinna were severely damaged under high As condition. Calcium concentration in the fronds of P. vittata was not significantly affected by the addition of As, but Ca concentration in the mature pinna significantly increased by As addition, consistent with the position appearing As toxicity. When no As was added, most of calcium precipitates distributed around the inner membrane of vacuole. But when the pinna appeared plasmolysis, more calcium precipitates resided outside the cell membrane and bigger particles evenly distributed in the cytoplasm. All the results indicated that Ca had a close relation with As toxicity in P. vittata.

Arsenic↗

PubMed2005

Zinc tolerance and accumulation in Pteris vittata L. and its potential for phytoremediation of Zn- and As-contaminated soil.

A field investigation and pot experiments were conducted to determine the potential of arsenic (As) hyperaccumulator, Pteris vittata L., to remediate sites co-contaminated with zinc (Zn) and As. We found that P. vittata L. had a very high tolerance to Zn and grew normally at sites with high Zn concentrations. In addition, P. vittata L. could effectively take up Zn into its fronds, with a maximum of 737 mg kg(-1) under field conditions. In pot experiments, the accumulated Zn concentration increased significantly as the Zn treatment was raised from 0 to 2000 mg kg(-1), with a maximum Zn accumulation of 0.22 mg pot(-1). Although the concentration of As in P. vittata L. was reduced by the addition of Zn, total frond accumulation of As was elevated when the Zn treatment was increased from 0 to 1000 mg kg(-1), with a maximum As accumulation of 8.3 mg pot(-1) in the presence of 1000 mg kg(-1) Zn. The high Zn tolerance, relatively high ability to accumulate Zn, and great capacity to accumulate As under conditions of suppression by high Zn suggest that P. vittata L. could be useful for the remediation of sites co-contaminated with Zn and As.

Arsenic↗

PubMed2005

Effects of arbuscular mycorrhizal inoculation on uranium and arsenic accumulation by Chinese brake fern (Pteris vittata L.) from a uranium mining-impacted soil.

A glasshouse experiment was conducted to investigate U and As accumulation by Chinese brake fern, Pteris vittata L., in association with different arbuscular mycorrhizal fungi (AMF) from a U and As contaminated soil. The soil used contains 111 mg U kg(-1) and 106 mg As kg(-1). P. vittata L. was inoculated with each of three AMF, Glomus mosseae, Glomus caledonium and Glomus intraradices. Two harvests were made during plant growth (two and three months after transplanting). Mycorrhizal colonization depressed plant growth particularly at the early stages. TF (transfer factor) values for As from soil to fronds were higher than 1.0, while those for roots were much lower. Despite the growth depressions, AM colonization had no effect on tissue As concentrations. Conversely, TF values for U were much higher for roots than for fronds, indicating that only very small fraction of U was translocated to fronds (less than 2%), regardless of mycorrhizal colonization. Mycorrhizal colonization significantly increased root U concentrations at both harvests. Root colonization with G. mosseae or G. intraradices led to an increase in TF values for U from 7 (non-inoculation control) to 14 at the first harvest. The highest U concentration of 1574 mg kg(-1) was recorded in roots colonized by G. mosseae at the second harvest. The results suggested that P. vittata in combination with appropriate AMF would play very important roles in bioremediation of contaminated environments characterized by a multi-pollution.

Arsenic↗

PubMed2006

Arbuscular mycorrhizae increase the arsenic translocation factor in the As hyperaccumulating fern Pteris vittata L.

Phytoremediation techniques are receiving more attention as decontaminating strategies. Phytoextraction makes use of plants to transfer contaminants from soil to the aboveground biomass. This research is devoted to study the effects of arbuscular mycorrhizae (AM) on growth and As hyperaccumulation in the Chinese brake fern Pteris vittata. We grew for 45 days P. vittata sporophytes, infected or not infected with the AM fungi Glomus mosseae or Gigaspora margarita, in a hydroponic system on quartz sand. As-treated plants were weekly fed with 25 ppm As. The As treatment produced a dramatic increase of As concentration in pinnae and a much lower increase in roots of both mycorrhizal and control plants. Mycorrhization increased pinnae dry weight (DW) (G. margarita = G. mosseae) and leaf area (G. margarita > G. mosseae), strongly reduced root As concentration (G. mosseae > G. margarita), and increased the As translocation factor (G. mosseae > G. margarita). The concentration of phosphorus in pinnae and roots was enhanced by both fungi (G. margarita > G. mosseae). The quantitatively different effects of the two AM fungi on plant growth as well as on As and P distribution in the fern suggest that the As hyperaccumulation in P. vittata can be optimized by a careful choice of the symbiont.

Arsenic↗