Potential of Pteris vittata L. for phytoremediation of sites co-contaminated with cadmium and arsenic: The tolerance and accumulation

Field investigation and greenhouse experiments were conducted to study the tolerance of Pteris vittata L. （Chinese brake） to cadmium （Cd） and its feasibility for remediating sites co-contaminated with Cd and arsenic （As）. The results showed that P. vittata could survive in pot soils spiked with 80 mg/kg of Cd and tolerated as great as 301 mg/kg of total Cd and 26.8 mg/kg of diethyltriaminepenta acetic acid （DTPA）-extractable Cd under field conditions. The highest concentration of Cd in fronds was 186 mg/kg under a total soil concentration of 920 mg As/kg and 98.6 mg Cd/kg in the field, whereas just 2.6 mg/kg under greenhouse conditions. Ecotypes of P. vittata were differentiated in tolerance and accumulation of Cd, and some of them could not only tolerate high concentrations of soil Cd, but also accumulated high concentrations of Cd in their fronds. Arsenic uptake and transportation by P. vittata was not inhibited at lower levels （〈20 mg/kg） of Cd addition. Compared to the treatment without addition of Cd, the frond As concentration was increased by 103.8% at 20 mg Cd/kg, with the highest level of 6434 mg/kg. The results suggested that the Cd-tolerant ecotype of P. vittata extracted effectively As and Cd from the site co-contaminated with Cd and As, and might be used to remediate and revegetate this type of site.

Arsenic uptake and transport of Pteris vittata L.as influenced by phosphate and inorganic arsenic species under sand culture

In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in Ashyperaccumulator, uptake and transport of arsenate （As（V）） and arsenite （As（Ⅲ）） were studied using Pteris vittata L. under sand culture. Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P. vittata. The reduction in As accumulation was greater in old fronds than in young fronds, and relatively weak in root and rhizome. Moderate increases, from 0.05 to 0.3 mmol/L, in phosphate reduced uptake of As（Ⅲ） more than As（Ⅴ）, while the reverse was observed at high concentrations of phosphate （≥1.0 mmol/L）. Phosphate apparently reduced As transport and the proportion of As accumulated in fronds of P. vittata when As was supplied as As（Ⅴ）. It may in part be due to competition between phosphorus and As（Ⅴ） during transport. In contrast, phosphate had a much smaller effect on As transport when the As was supplied as As（Ⅲ）. Therefore, the results from present experiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P. vittata, especially in the fronds, when exposed to As（Ⅴ）, but the suppression of phosphate to As transport may be insignificant when P. vittata exposed to As（Ⅲ） under sand culture conditions. The finding will help to understand the interaction of P and As during their uptake process in P. vittata.

EFFECT OF ACTIVE COMPOUNDS ISOLATED FROM PTERIS SEMIPINNATA L ON DNA TOPOISOMERASES AND TYROSINE PROTEIN KINASE AND EXPRESSION OF C-MYC IN LUNG ADENOCARCINOMA CELLS

Objective: To study the effect of active compound 6F and A from Pteris semipinnata L.(PsL) on the activities of DNA topoisomerase (TOPO) I and II, activities of cytosolic and membrane TPK, and expression of oncogene c-myc in lung adenocarcinoma cells. Methods: The effect of compound 6F and A on activities of cytosolic and membrane TPK was measured by scintillation counting; the effect of compound A on expression of oncogene c-myc was determined by flow cytometry indirect fluorimetry. Results: compound 6F and A could inhibit the activities of TOPO I, and they strongly inhibited the TOPO II in 0.01 mg/L and 10.0 mg/L respectively. Compound A slightly inhibited the activities of membrane TPK, but not the cytosolic one. Compound A could inhibit the expression of oncogene c-myc. Conclusion: Topoisomerases are target of compound 6F and A. Compound A could slightly inhibit the activities of TPK, and showed an inhibitory effect on the expression of oncogene c-myc.

Production of polyunsaturated fatty acids in the fern Pteris ensiformis suspension culture

Polyunsaturated fatty acids (PUFAs) are essential nutrients for a healthy diet and adequate human development (1)The human consumption of PUFAs is steadily increasing, but the production of fish oil, the main source of PUFAs for human consumption, is declining (2)Increasing PUFA demand has therefore raised an interest in achieving these PUFAs from alternative sources that are more economical and sustainable.

Effect of phosphorus on arsenic accumulation in As-hyperaccumulator Pteris vittata L. and its implication

Pot experiment was conducted to understand the effect of phosphorus on arsenic accumulation in As-hyperaccumulator Chinese brake (Pteris vittata L.). It is shown that arsenic concentrations in the fronds and rhizoids, the arsenic bioaccumulation factor, and the total arsenic in the fronds were not influenced significantly under low levels of phosphorus (≤400 mg/kg) and increased sharply under high levels of phosphorus (】400 mg/ kg). The discovery implies that the efficiency of arsenic removal in phytoremedia-tion using the hyperaccumulating plant can be greatly elevated by the phosphorus addition at high rates. The interaction between the accumulation of phosphorus and that of arsenic in plant was stimulated mutually. The result represents that Chinese brake is a good material for plant physiologist to conduct comparative and mechanism studies on the uptake behaviors of phosphorus and arsenic, and phosphorus is also a potential accelerator for phytoremediation of arsenic-contaminated soils.

Role of trichome of Pteris vittata L. in arsenic hyperaccu-mulation

Environmental scanning electron microscope (ESEM) fitted with an energy disper- sive X-ray microanalyzer (EDX) was used to investigate the surface micromorphology and arse- nic (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 μm and with an average diameter of 28 μm, 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 con- tained 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.

Distributions of arsenic and essential elements in pinna of arsenic hyperaccumulator Pteris vittata L.

The distributions of arsenic and 6 essential elements in the pinna of As hyperaccumulator, Pteris vittata L., were studied using synchrotron radiation X-ray fluorescence (SRXRF). Significant correlation between the distribution and mobility of the elements revealed that SRXRF study on the elemental distribution was feasible to inspect the transportations of elements in plants. The distribution of As in the pinna showed that As had great abilities to be transported in xylem vessels and from xylem to mesophyll. The distribution of K, one of the most mobile elements in plants, was similar to that of As, whereas the distributions of Fe and Ca with less mobility in plants were almost opposite to that of As in the pinna.

Elemental allelopathy by an arsenic hyperaccumulating fern,Pteris vittata L.

Aims the functional advantages of arsenic(As)hyperaccumulation by plants are poorly understood.One proposed benefit,termed ele-mental allelopathy,occurs when hyperaccumulated As is cycled from the plant back into the top layer of soil,allowing As hyperaccu-mulators to gain an advantage over intolerant species by increasing soil As concentrations([As])underneath their canopy.to date,there are no studies that detail the presence of increased soil[As]associ-ated with As hyperaccumulators.In this study,we documented vari-ation in the soil[As]associated with the Chinese brake fern,Pteris vittata L.and also compared the effects of environmentally relevant soil and solution[As]on competitor plant growth.Methods Four populations of P.vittata were identified in central Florida,USA.P.vittata tissue samples and soil samples were collected at the base of and at 3 m away from ferns in each population(n=36).Five sample locations were randomly selected from each site,and soils from the base and 3 m away from each fern were collected to examine the effects of naturally occurring soil[As]on the germination and growth of a potential competitor plant(Oxalis stricta).Solutions with increasing[As]were also used to examine the threshold for negative effects of[As]on O.stricta growth.[As]were measured using inductively coupled plasma mass spectrometry(ICP-MS).Important Findings Overall,soil[As]from the base of ferns was nearly twice that of soil 3 m away indicating that ferns hyperaccumulate As.However,ferns and their associated soil,contained different[As]depending on their col-lection site,indicating that these populations accumulate and use[As]differently.O.stricta growth decreased and germination was delayed as solution and soil[As]increased.However,the relative distance from the fern that the soil was collected from did not affect growth,which would be expected with elemental allelopathy.Our results show that P.vittata is associated with higher soil[As]and these concentrations are sufficient to inhibit growth of competitors.However,the absence of a strong inhibitory relationship associated with proximity to the fern across all locations suggests that the possible functional advantages of elemental allelopathy may depend on site specific characteristics.

Accumulation and Speciation of Arsenic in Pteris vittata Gametophytes and Sporophytes: Effects of Calcium and Phosphorus

Dear Editor, Environmental arsenic (As) contamination of both soil and water systems is a worldwide problem, and As can enter the human food chain through contaminated agricultural products and drinking water and contribute to the development of lung.

三叶鬼针草和黑心菊根系分泌物对井栏边草配子体叶绿素荧光特性的影响

研究了入侵植物三叶鬼针草（Bidens pilosa）和非入侵植物黑心菊（Rudbeckia hirta）的根系分泌物对三叶鬼针草入侵和潜在扩散区代表蕨类植物井栏边草（Pteris multifida）配子体叶绿素荧光参数的影响.结果表明,与对照相比,除非光化学荧光淬灭系数外,三叶鬼针草和黑心菊均可降低井栏边草其他叶绿素荧光参数.这种抑制作用随2种植物根系分泌物浓度升高而增强.处理第十天,抑制效果最明显.当三叶鬼针草和黑心菊根系分泌物浓度高于12.5％时,在处理4-10d后,配子体各叶绿素荧光参数均受到显著影响.综上所述,三叶鬼针草和黑心菊对井栏边草配子体光合能力均可产生抑制作用,且三叶鬼针草抑制作用更强.

植物生长调节素对西南凤尾蕨组织培养的影响

以西南凤尾蕨(Pteris wallichiana)的成熟孢子为外植体,以MS、1/2MS为基本培养基,研究了植物生长调节素对西南凤尾蕨离体组织培养的影响。结果表明,不同细胞分裂素和生长激素配比对西南凤尾蕨的组织培养影响不同,最适诱导培养基为MS+6-BA 1.0 mg/L+NAA 2.0 mg/L;最适增殖培养基为MS+6-BA 1.0 mg/L+NAA 1.0 mg/L+AC 1.0 g/L,最高增殖倍数为7.05倍;最适生根壮苗培养基为1/2MS+6-BA 0.5 mg/L+NAA 0.5 mg/L,生根率达到90%以上。

彩叶凤尾蕨孢子离体繁殖及组织培养

彩叶凤尾蕨 Pteris aspericaulis Wall var.tricolor Moore.(中国新记录),又名三色凤尾蕨,生长在云南南部,是一种稀有的观赏植物,叶片纵向呈红、白、绿三色条纹,叶片中间部份(包括叶脉)为红色,紧接着为白色,叶边缘部份为绿色,在温度高(25℃以上)温度大的条件下,三种色彩更为鲜明,深受人们喜爱。试验材料为野外采回的长有孢子束群的叶片,将叶片在0.1%升汞溶液中浸10分钟,无菌水冲洗5次,在无菌条件下,将孢子束群的束群盖剥开。

微波辅助提取凤尾蕨中总黄酮的工艺研究

以黄酮提取率为考察指标,采用单因素试验和正交试验,进行了微波辅助乙醇提取凤尾蕨(Pteris multifide Poir)中总黄酮的研究,得到微波辅助提取凤尾蕨中总黄酮的最佳工艺条件为乙醇体积分数60%,料液比1∶60(g∶m L),微波功率320 W,微波提取时间60 s。此工艺条件下,凤尾蕨中总黄酮的提取率为3.318%。

基于Petri网和故障树的变电站故障诊断方法

针对变电站的设备组成及联接特点,利用Petri网(PN)的图形特性,提出了一种基于Petri网和故障树的变电站故障诊断模型和诊断方法.利用PN建立了可能性故障区域诊断模型,利用PN和故障树建立故障元件诊断模型.详细给出了变电站可能的故障区域诊断方法和变电站故障元件诊断方法.在故障元件的诊断中,建立了针对可能故障区域的面向设备的子Petri网模型,降低了诊断的复杂性.仿真研究表明,利用该方法可以比较容易实现变电站故障诊断系统,且有高的准确性和诊断效率.

Ent-11α-Hydroxy-15-oxo-kaur-16-en-19-oic-acid Inhibits Growth of Human Lung Cancer A549 Cells by Arresting Cell Cycle and Triggering Apoptosis

Objective： To examine the apoptotic effect of ent-llα-hydroxy-15-oxo-kaur-16-en-19-oic-acid （5F）, a compound isolated from Pteris semipinnata L （PsL）, in human lung cancer A549 cells. Methods： A549 cells were treated with 5F （0-80 lag/ml） for different time periods. Cytotoxicity was examined using a Ml-I- method. Cell cycle was examined using propidium iodide staining. Apoptosis was examined using Hoechst 33258 staining, enzyme-linked immunosorbent assay （ELISA） and caspase-3 activity analysis. Expression of representative apoptosis-related proteins was evaluated by Western blot analysis. Reactive oxygen species （ROS） level was measured using standard protocols. Potential interaction of 5F with cisplatin was also examined. Results： 5F inhibited the proliferation of A549 cells in a concentration- and time-dependent manner. 5F increased the accumulation of cells in sub-G1 phase and arrested the cells in the G2 phase. Exposure to 5F induced morphological changes and DNA fragmentation that are characteristic of apoptosis. The expression of p21 was increased. 5F exposure also increased Bax expression, release of cytochrome c and apoptosis inducing factor （AIF）, and activation of caspase-3. 5F significantly sensitized the cells to cisplatin toxicity. Interestingly, treatment with 5F did not increase ROS, but reduced ROS production induced by cisplatin. Conclusion： 5F could inhibit the proliferation of A549 cells by arresting the cells in G2 phase and by inducing mitochondrial-mediated apoptosis.

浙江省2种蕨类植物新记录

报道了2种分布于浙江的蕨类新记录植物,分别是蹄盖蕨科(Athyriaceae)的沼生蹄盖蕨(Athyrium palustre Seriz.)(中国大陆分布新记录)和凤尾蕨科(Pteridaceae)的擬乌来凤尾蕨(Pteris pseudowulaiensis Y.S. Chao)(浙江省分布新记录),提供了形态描述与生态照片,并讨论了该发现的生物地理学意义,凭证标本保存在浙江自然博物院标本馆(ZM).

湿地超富集植物对重金属矿山生态修复的比较分析

重金属矿山地区由于重金属含量较高,严重影响矿山生态环境。为了开发降低重金属矿山土壤污染的方法,本研究旨在揭示湿地超富集植物对重金属矿山生态修复的影响。本研究以龙葵(Solanum nigrum)和大叶井口边草(Pteris nervosa)为试验植物,用采自陕西省府谷县已停止开采的矿山中的土壤对其进行单作和间作盆栽培养,并分析相关实验数据。试验结果显示,种植30 d后,单作和间作种植湿地超富集植物明显降低了土壤中铬元素、铅元素、铜元素以及镉元素的含量,间作对重金属吸收能力最好(P<0.05)。种植30 d后,单作和间作种植湿地超富集植物均显著提高了植物多样性指数,间作对植物多样性指数的提升效果最明显(P<0.05)。本研究结果表明湿地超富集植物在重金属矿山生态修复中具有积极影响,可有效降低地区土壤的重金属含量,同时改善地区的物种多样性。

砷超富集植物中元素的微区分布及其与砷富集的关系

摘要 通过同步辐射X射线荧光方法(SRXRF)研究 As超富集植物大叶井口边草(Pteris Cretica L varnervosa Thu)根、叶柄和叶片(羽片)中 As及其他 10种元素的微区分布和 As的吸收及转运特点.结果表明,AS在根部具有向维管柱转运的趋势,在叶脉中具有向近轴皮层转运的趋势,但是在叶柄中却被限制在维管柱中.在羽叶中AS主要富集在叶肉组织中,叶表皮细胞的AS含量相对较低.在羽叶、叶脉和叶柄中,As的微区分布与K,Ca,Mn,Fe,Cu和Zn等阳离子元素分布规律非常相似,它有]在转运过程中很可能存在协同作用,但是在羽叶中As与O和Br存在显著的竞争关系或桔抗作用.

EXAFS study on arsenic species and transformation in arsenic hyperaccumulator

Synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperaccumulator, Cretan brake (Pteris cretica L. var ner-vosa Thunb). It showed that the arsenic in the plant mainly coordinated with oxygen, except that some arsenic coordinated with S as As-GSH in root. The complexation of arsenic with GSH might not be the predominant detoxification mechanism in Cretan brake. Although some arsenic in root presented as As(V) in Na2HAsO4 treatments, most of arsenic in plant presented as As(III)-O in both treatments, indicating that As(V) tended to be reduced to As(III) after it was taken up into the root, and arsenic was kept as As(III) when it was transported to the above-ground tissues. The reduction of As(V) primarily proceeded in the root.