Growth Response and Metal Accumulation of Sedum alfredii to Cd/Zn Complex-Polluted Ion Levels

Sedum alfredii Hance has been identified as a new Zn-hyperaccumulator native to China. In this study, responses and metal accumulation of S alfredii were examined under Zn/Cd complex polluted conditions. The results showed that optimal growth of S alfredii in terms of the maximum dry matter yield was observed at Zn/Cd complex level of 500/100 mumol/L. Plant cadmium (Cd) or zinc (Zn) concentrations increased with increasing Cd or Zn supply. During the 20 d treatment, the highest Cd concentration in the leaves reached 12.1 g/kg at Zn/Cd level of 50/400 mumol/L and that of Zn in the stems was 23.2 g/kg at Zn/Cd level of 1000/50 mumol/L. The distribution of Cd in different plant parts decreased in the order: leaf > stem greater than or equal to root, whereas that of Zn was: stem > leaf greater than or equal to root. The accumulation of Cd and Zn in the shoots and roots of S. alfredii increased with the increasing of Zn/Cd supply levels, peaked at Zn/Cd levels of 250/400 and 500/100 mumol/L, respectively. The highest Cd and Zn uptake by the shoots was approximately 5 and 11 mg/plant, and was over 20 and 10 times higher than those in the roots, respectively. Zn supply at levels less than or equal to 500 mumol/L increased plant Cd concentrations, whereas high Zn supply decreased root Cd but did not affect leaf Cd concentrations in S alfredii Low Cd supply increased Zn concentration in the leaves, but Cd supply higher than 50 mumol/L considerably reduced root Zn concentrations, especially at low Zn level. These results indicate that S. alfredii can tolerate high Zn/Cd complex levels and has an extraordinary ability to hyperaccumulate not only Zn but also Cd. It could provide a new valuable plant material for understanding the mechanisms responsible for co-hyperaccumulation of Zn and Cd as well as for phytoremediation of the Cd/Zn complex polluted soils.

Differences of Uptake and Accumulation of Zinc in Four Species of Sedum

Four species of Sedum L. were grown in nutrient solution for the comparison of their Zn uptake and accumulation. S. alfredii Hance showed much greater tolerance to Zn than the other three species. Shoot and root yields of S. sarmentosum Bunge, S. bulbiferum Makino, and S. emarginatum Migo decreased with increasing Zn concentration in the solution, while shoot and root yields of S. alfredii increased when Zn concentration was ≤80 mg·L -1. At 80 mg·L -1 Zn, Zn concentration in shoots of S. alfredii reached 19.09 mg·g -1. S. alfredii was also more efficient in Zn translocation from roots to shoots, while Zn concentration in shoots was much higher than in roots. However, this was not the case for the other three species. The results showed that S. alfredii is a Zn hyperaccumulator and could be useful for the phytoremediation of Zn-contaminated soils.

Sedum alfredii : A New Lead-Accumulating Ecotype

hi a survey of plant population, Sedum alfredii Hance, a new lead (Pb)-tolerant and lead (Pb)accumulating ecotype, was found in an old Pb/Zn mining area in Zhejiang Province of China. The growth and Pb content of plant ecotypes being able to and unable to accumulate Pb were studied by hydroponic culture with different concentrations of Pb(NO3)(2). Growth of shoots of accumulating ecotype was not affected by Ph treatments up to 320 mg/L, whereas that of non-accumulating ecotype was inhibited in all Ph treatments. The Ph concentrations in the roots and shoots of accumulating ecotype increased with increasing of Pb level in the nutrient solution. The maximum Ph concentrations in the shoots and roots of accumulating ecotype were 514 mg/kg and 13 922 mg/kg, 2.27 times and 2.62 times as much as that of non-accumulating ecotype, respectively. The highest rate of Pb accumulation of accumulating ecotype was 8.62 mug/plant/d, 7.16 times as much as that of non-accumulating ecotype. Due to its fast growth rate and high Pb-accumulating ability, from a phytoremediation perspective, accumulating ecotype of S. alfredii is a potential plant species for Pb removal from contaminated soils.

Subcellular Distribution of Cadmium in Mining Ecotype Sedum alfredii

The mining ecotype Sedum alfredii Hance could tolerate and grow normally in a nutritive solution containing cadmium (Cd) as high as 400 mumol/L. Under such a high Cd concentration, the subcellular accumulation of Cd in root, stem and leaf of this plant was found to be the highest in the cell wall, less in the soluble fraction and lowest in the cell organs. The mode of subcellular distribution of Cd in the mining ecotype S. alfredii was similar to other hyper accumulators of heavy metals, in which Cd was distributed more in the aerial part of plant. The results suggest that the mining ecotype S. alfredii is a new species of Cd hyperaccumulator.

Photooxidation in Leaves of Facultative CAM Plant Sedum spectabile at C_3 and CAM Mode

The switch from C-3 to CAM pathway was induced by water stress in a C-3/CAM intermediate plant Sedum spectabile Boreau. Typical CAM criteria were observed upon 15 d of withholding water. Leaf delta(13)C value (-%) and water content showed a linear correlation fashion. Chlorophyll fluorescence parameters and antioxidative capacity were altered by water stress. Phi(PSII) and q(P) were reduced by 50% and 34% of the control, respectively, while NPQ rose ca. 180%. SOD activity and ability to scavenge DPPH. free radical went down but membrane permeability changed slightly. However, when an additional photooxidation by MV with high PPFD was carried out with leaf discs from watered (C-3 mode) and drought plants (CAM mode), q(P) and Phi(PSII) in leaves at induced CAM mode stage continuously decreased to a very low level. High 1 - q(P) value (0.86) and 1 - q(P)/NPQ ratio (>1) indicated the presence of high reduction state and unbalance of light energy budget. Together with the marked loss of membrane integral, it was evidenced that photooxidative damage was more serious in the induced CAM mode than in the C-3 mode. No advantage of photooxidation tolerance was found at the induced CAM expression stage of the facultative CAM plant, as compared with its C-3 mode stage, and also with the constitutive CAM plants reported previously. The differences in photooxidation sensitivity between the inducible CAM expressing plant and the constitutive CAM plant were discussed.

东南景天Sedum alfredii修复重金属污染土壤的研究进展

植物修复是净化重金属污染土壤最有潜力的原位修复技术之一,因地制宜地选择植物修复材料是大田植物修复成功实施的关键。国内外已发现的众多重金属超积累植物具有不同的生理特性,其中东南景天Sedum alfredii可忍耐和富集镉(Cd)和锌(Zn)等多种重金属,并且具有生长迅速的特点,是研究植物修复技术的模式植物之一。综述了东南景天对重金属的耐性、吸收、转运及解毒机制,阐明东南景天研究过程中存在的问题,并对其研究前景和方向作了简要分析,为重金属污染土壤植物修复工作的深入开展提供参考。

景天属(Sedum)8种植物茎的解剖学研究

利用光学显微镜 ,首次观察并报道了安徽产景天属 (Sedum ) 8种植物茎的解剖结构 ;结果表明 ,景天属植物茎由表皮 (一层 )、皮层 (数层 )、维管柱 (木质部、韧皮部、髓 )三部分构成 ,并明确提出了肉质植物茎的解剖学处理方法 .

垂盆草(Sedum sarmentosum)水提物对草鱼(Ctenopharyngodon idellus)脂肪性肝损伤治疗效果研究

为了研究景天科中药植物垂盆草(Sedum sarmentosum)水提物对草鱼(Ctenopharyngodon idellus)脂肪性肝损伤治疗作用及机理,本试验通过对连续投喂6周8.1%(鱼油5%+大豆油3.1%)高脂饲料建立的草鱼脂肪性肝损伤模型,投喂添加1200mg/kg、300mg/kg浓度的垂盆草饲料进行6周治疗,测定血清主要脂肪代谢相关生化指标、制作肝脏病理切片及应用半定量RT-PCR技术检测肝细胞脂肪代谢相关酶肉碱棕榈酰转移酶I(CPT-1)、过氧化物酶体增殖物激活受体-α(PPAR-α)及肿瘤坏死因子-α(TNF-α)m RNA相对表达量变化。结果表明:连续投喂6周的高脂饲料草鱼血清生化指标发生显著变化,组织病理学观察肝细胞发生严重的脂肪变性,故已成功建立了草鱼脂肪性肝损伤模型。通过6周治疗,1200mg/kg剂量组、300mg/kg剂量组均可显著降低模型动物的谷丙转氨酶(ALT)、谷草转氨酶(AST)、甘油三酯(TG)和总胆固醇(CHO)(P<0.01);组织病理学观察显示,1200mg/kg、300mg/kg剂量组的肝细胞脂肪变性程度与高脂组相比有一定程度的改善;同时半定量RT-PCR检测结果表明:用药1200mg/kg、300mg/kg剂量组草鱼肝脏CPT-1 m RNA、PPAR-αm RNA相对表达量均显著高于高脂组(P<0.01),且1200mg/kg剂量组TNF-αm RNA表达量显著低于高脂组(P<0.01)。本研究结果表明肝脏是草鱼脂肪沉淀的主要场所,饲料中添加垂盆草水提物可对8.1%高脂饲料引起的草鱼肝脂肪性组织损伤具有治疗作用,该治疗作用与促进肝细胞脂质代谢途径有关。

景天品种Sedum‘Autumn Joy’扦插繁殖研究

对景天属优良品种Sedum‘Autumn Joy’在生长季内不同时期的扦插生根成活率进行研究。结果表明,Sedum‘Autumn Joy’扦插在全年的生长季内任一时间段都可进行,其中春季扦插生根率可以达100%,发根点达3-4个;夏季扦插时较低,平均约为40%;9-10月可达80%-90%。景天扦插不需要施用任何生根激素,在一般的温室内即可进行,生产成本低,非常适合大面积繁殖。

两种生态型东南景天(Sedum alfredii Hance)根系互作效应对植株生长及吸收利用土壤Zn的影响

采用盆栽套种方法探讨了不同程度根系互作对两种生态型东南景天的生长和吸收利用土壤Zn的影响,以及超积累生态型东南景天的根系是否能活化土壤中难利用态Zn。不同程度的根系互作采用不同隔膜处理,即无隔膜处理、400目尼龙筛布隔开和PVC板隔开。结果发现,当两种生态型东南景天套种时,不同程度的根系互作对非超积累生态型东南景天的地上部和根系的生物量、根系Zn含量有显著影响。当与超积累生态型东南景天的根系完全交互作用或采用400目尼龙筛布隔开时,非超积累生态型的根系Zn含量显著增加,其地上部和根系生物量比其单种时显著减少。这些结果间接表明,超积累生态型东南景天根系能够活化土壤中的难溶态Zn。

Zinc adsorption and desorption characteristics in root cell wall involving zinc hyperaccumulation in Sedum alfredii Hance

Radiotracer techniques were employed to characterize 65Zn adsorption and desorption in root-cell-wall of hyperac-cumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) species of Sedum alfredii Hance. The results indicated that at the end of a 30 min short time radioisotope loading period, comparable amounts of 65Zn were accumulated in the roots of the two ecotypes Sedum alfredii, whereas 2.1-fold more 65Zn remains in NHE root after 45-min desorption. At the end of 60 min uptake period, no difference of 65Zn accumulation was observed in undesorbed root-cell-wall of Sedum alfredii. However, 3.0-fold more 65Zn accumulated in desorbed root-cell-wall of NHE. Zn2+ binding in root-cell-wall preparations of NHE was greater than that in HE under high Zn2+ concentration. All these results suggested that root-cell-wall of the two ecotypes Sedum alfredii had the same ability to adsorb Zn2+, whereas the desorption characteristics were different, and with most of 65Zn binding on root of HE being available for loading into the xylem, as a result, more 65Zn was translocated to the shoot.

安徽景天属(Sedum)植物叶表皮研究

利用光学显微镜和扫描电子显微镜观察了安徽省１２ 种景天属（Ｓｅｄｕｍ） 植物的叶表皮，统计并测量了气孔类型、气孔大小、气孔密度及气孔指数等，描述了表皮角质膜、蜡质纹饰及气孔外拱盖的有关特征。结果表明：景天属植物叶表皮气孔器为不等细胞型。气孔器类型、表皮细胞形状及垂周壁式样、角质膜、蜡质纹饰等，种间无差异或极小，而气孔大小、气孔器分布特征、气孔密度、表皮毛等种间差异较大。建议在种间区分上将差异大的特征作为种间第一特征，将差异小的特征作为次级特征。

Comparison between sequential and single extraction procedures for metal speciation in fresh and dried Sedum Plumbizincicola

Sequential and single extraction procedures were applied to both fresh and dried Sedum Plumbizincicola leaves and stems.The extractants, different from those of soil, sediment or sewage sludge metal fractions, were water, 80%(v/v) ethanol, 1 mol/L Na Cl,2% HAc and 0.6 mol/L HCl. Zn, Cd and Cu in the extracts and samples were measured by flame atomic adsorption spectrometry. In sequential extraction procedures, water soluble form and ethanol soluble form are the main fractions for Zn, while water soluble form and Na Cl soluble form for Cd, and comparatively uniform distribution for Cu with the residue form most and HCl soluble form second. Single extraction procedures are used to compare the extraction efficiencies of the five reagents to screen appropriate extractants and operating conditions for liquid extraction to deal with large amount of harvested metal-contained biomass, which will pose a threat to the environment if treated improperly. The sequences of extraction efficiencies are HCl>Na Cl≈HAc>Water≈Ethanol for Zn and HCl≈Na Cl≈HAc>Water>Ethanol for Cd. As for Cu, all the five extractants cannot effectively extract Cu, but HCl achieves a higher efficiency(>70% in fresh samples, and 45%-60% in dried samples). Besides, extraction efficiencies for most extractants in fresh samples are higher than those in dried samples, and extraction efficiencies of stems and leaves for the five extractants are close. The two extraction procedures can obtain high degree of accuracy with the relative standard deviation(RSD)lower than 10%, and metal recoveries are controlled between 80%-120% with most of 90%-110%.

Screening of Anti-tumor Effective Extracts from Sedum bulbiferum Makino and HPLC Determination of Quercetin and Kaempferol in This Herbal Medicine

[Objectives] To investigate the anti-tumor activity of Sedum bulbiferum Makino in vitro,and establish a HPLC method for determination of quercetin and kaempferol in S. bulbiferum. [Methods] The inhibitory activities of different extracts and total flavonoids of S. bulbiferum on proliferation of three kinds of cancer cells( Hep G2,EC109,SW480) were tested by MTT assay. HPLC method for determination of quercetin and kaempferol in S. bulbiferum was established. [Results]The growth and proliferation of the three kinds of cancer cells were all significantly inhibited by ethyl acetate fraction and total flavonoids isolated from S. bulbiferum. With each extraction concentration increasing,stronger anti-tumor activity was found. The linear ranges of quercetin and kaempferol were 0. 03-0. 36 μg( R = 0. 999 9) and0. 08-0. 96 μg( R = 0. 999 9),and the average recoveries were 98. 90%( RSD = 1. 15%) and 98. 27%( RSD = 1. 70%),respectively.[Conclusions]S. bulbiferum has significant anti-tumor activity in vitro. The HPLC method established was accurate,reproducible,and could be used for quality control of this crude drug.

Differential generation of hydrogen peroxide upon exposure to zinc and cadmium in the hyperaccumulating plant specie(Sedum alfredii Hance)

Sedum alfredii Hance has been identified as zinc(Zn) and cadmium(Cd) co-hyperaccumulator.In this paper the relationships of Zn or Cd hyperaccumulation to the generation and the role of H2O2 in Sedum alfredii H.were examined.The results show that Zn and Cd contents in the shoots of Sedum alfredii H.treated with 1000 μmol/L Zn2+ and/or 200 μmol/L Cd2+ increased linearly within 15 d.Contents of total S,glutathione(GSH) and H2O2 in shoots also increased within 15 d,and then decreased.Total S and GSH contents in shoots were higher under Cd2+ treatment than under Zn2+ treatment.However,reverse trends of H2O2 content in shoots were obtained,in which much higher H2O2 content was observed in Zn2+-treated shoots than in Cd2+-treated shoots.Similarly,the microscopic imaging of H2O2 accumulation in leaves using H2O2 probe technique showed that much higher H2O2 accumulation was observed in the Zn2+-treated leaf than in the Cd2+-treated one.These results suggest that there are different responses in the generation of H2O2 upon exposure to Zn2+ and Cd2+ for the hyperaccumulator Sedum alfredii H.And this is the first report that the generation of H2O2 may play an important role in Zn hyperaccumulation in the leaves.Our results also imply that GSH may play an important role in the detoxification of dissociated Zn/Cd and the generation of H2O2.

Integrated Fertilization Regimes Boost Heavy Metals Accumulation and Biomass of Sedum alfredii Hance

The hyperaccumulator Sedum alfredii Hance(S.alfredii)may be employed for zinc(Zn)and cadmium(Cd)-polluted soil remediation.However,the low phytoremediation efficiency,related to the low biomass production,limits its use with that purpose.In this experiment,nitrogen(N),phosphorus(P),and potassium(K)fertilizers,and organic manure were applied to investigate the phytoremediation ability of S.alfredii.Hydroponic and pot experiments were conducted using Zn-Cd polluted soil.The hydroponic experiment indicated that appropriate fertilizer application could increase(p<0.05)the amount of accumulated Zn and Cd in S.alfredii.When N supply ranged from 0.5 to 2.5 mmol L^(−1),it could improve growth and accumulation of Zn and Cd in whole plants of S.alfredii.The 1 mmol L^(−1) N was an optimal N dosage for shoot biomass production and Cd accumulation in shoots,while the 2.5 mmol L^(−1) was an optimal N dosage for Zn accumulation in shoots.Both low(<0.05 mmol L^(−1))and high(>0.8 mmol L^(−1))P supply decreased growth,and Zn/Cd accumulation in whole plants of the studied species.The 0.1 mmol L^(−1) P was an optimal dosage for S.alfredii biomass production and Zn/Cd accumulation in shoots.The supply levels within the range from 0.3 to 1 mmol L^(−1) K could significantly improve the biomass production of S.alfredii and its capability to accumulate Zn and Cd in the biomass.The 0.5 mmol L^(−1) K was an optimal dosage for the whole biomass production and Zn accumulation in shoots,while the 1 mmol L^(−1) was an optimal K dosage for Zn accumulation in shoots,which was 17.2%higher than the control.Moreover,the soil pot experiment showed that the combination of organic(fermented manure)and inorganic fertilizers made significant effects on the Zn and Cd-polluted soil remediation by S.alfredii.These effects varied,however,with the application of different proportions of N,P,K and organic matter.The Zn accumulation by S.alfredii reached the highest efficiency ability under the highest fertilizer mixing rate(N:50 mg kg^(−1),P:40 mg kg^(−1),K:100 mg kg^(−1),organic matter:1%).Even more,S.alfredii showed the strongest ability to accumulate Cd with a lower fertilizer mixing rate(N:25mg kg^(−1),P:20mg kg^(−1),K:50 mg kg^(−1),organic matter:0.5%).

Optimization of Extraction Conditions for SOD in Sedum aizoon by the Response Surface Method

This paper aimed to optimize extracting conditions of SOD in Sedum aizoon by response surface method. First,the single factor optimization tests were carried out. Three single factors were time,p H and liquid-solid ratio respectively. By Design expert 8. 0. 5 software,17 kinds of test scheme were designed. The protein yield of each scheme was obtained,and Design expert 8. 0. 5 software was used to conduct variance analysis and interactive analysis among factors,to obtain the corresponding mathematical model. The results showed that in single factor experiments,the optimal time was 1 h,p H was 7. 8,and liquid-solid ratio was 15:1. The interactive analysis indicated that the optimal scheme for extracting SOD in Sedum aizoon was time of 0. 98 h,p H of 7. 79,liquid-solid ratio of 13. 71:1. By the method of pyrogallol autoxidation,the extracted SOD enzyme activity was measured,namely 12 U/g. The results could provide a reference for further utilization and research of Sedum aizoon resource.

Reactive oxygen species metabolism during the cadmium hyperaccumulation of a new hyperaccumulator Sedum alfredii (Crassulaceae)

Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted sites. Malondialdehyde （MDA）, reactive oxygen species （ROS） and antioxidases （catalase （CAT）; superoxide dismutase （SOD）; peroxidase （POD）） in the leaf were determined when S. alfredii was treated for 15 d with various CdC12 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2＇,7＇-dichlorofluorescein （DCF）, which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.

Application of Sedum Plants in the Urban Landscape Greening

From the angles of the biological characters and ornamental characters of Sedum plants,several kinds of outstanding Sedum plants applied in the current landscape greening were introduced.The application ways of Sedum plants in the garden projects were discussed,which provided reference for selecting the plant materials in the garden landscape greening projects.

Screening of Primers for DNA Barcoding of Sedum Plants

[ Objective] This study aimed to screen primers for DNA barcoding of Sedum plants. [ Method] Sedum lineare Thunb., S. spectabile Boreau, S. ta- tarinowii Maxim, S. aizoon L. and S. sarmentosum Bunge were used as experimental materials. Nuclear DNA and chloroplast DNA were extracted from these five Sedum plants with CTAB method for primer screening by PCR amplification. PCR products were detected by agarose gel electrophoresis. [ Result] Four sequences suitable for DNA barcoding of Sedum plants were preliminarily screened from six candidate sequences （psbA-trnH, ropB, rbcL, rpoC1, ITS 2, marK）, including psbA-trnH, ropB, rpoC1 and ITS 2. The amplification rate of these four sequences reached 100%. [ Conclusion] This study provided basis for DNA barcoding of Sedum plants.