湖北省典型茶园土壤重金属污染状况及评价

通过对湖北省61个典型茶园的土壤重金属Cu、Ph、As、Hg、Cd和Cr的含量测定,明确了湖北省典型茶园土壤重金属污染状况.结合土壤环境质量评价国家标准,采用单因子污染指数和内梅罗综合污染指数法,对湖北省典型茶园土壤重金属污染状况进行了分析评价.结果表明,湖北省茶园土壤环境质量状况良好,符合国家土壤环境质量标准(二级),处于清洁和尚清洁级标准的茶园比例分别为85.25%和13.11%,仅有1个茶园出现中度污染.茶园土壤重金属Pb、As和Hg的含量均未超标,个别茶园土壤重金属Cu、Cd和Cr出现超标现象.     

福安市社口镇茶园土壤重金属含量与安全质量评价

测定了福安市社口镇茶场等6个茶园土壤砷（As）、镉（Cd）、铬（Cr）、铜（Cu）、汞（Hg）和铅（Pb）的含量,并结合无公害、有机茶园土壤环境标准和茶园土壤污染分级标准,采用单因子污染指数法和Nemerow污染指数法进行污染评价。结果表明,社口镇茶园土壤环境质量良好,符合无公害茶园土壤环境标准,6个茶园土壤的As、Cd、Cr、Cu、Hg和Pb单项污染指数均小于1.0,综合污染指数也都小于0.7;参照有机茶园土壤环境标准,除吉洋村茶园土壤的Pb单项污染指数略大于1.0外,其余茶园土壤的As、Cd、Cr、Cu、Hg和Pb单项污染指数均小于1.0,吉洋村和山里村茶园的综合污染指数介于0.7-1.0之间、为警戒级,其它茶园土壤的综合污染指数都小于0.7,符合有机茶园土壤质量标准。     

青岛市花生产地土壤环境质量的现状分析

对青岛市花生产地土壤重金属Cd、Hg、As、Pb、Cr、Cu、Zn和Ni的含量进行了调查分析,并采用单项质量指数与综合质量指数相结合的方法对环境质量状况进行了评价。结果表明各重金属的平均含量均低于“食用农产品产地环境质量评价标准”（HJ 332-2006）规定的限值,土壤环境质量定为1级,属于清洁水平,适宜发展无公害花生。但莱西一个监测点的土壤样品重金属Cu、Ni含量超标。若以国家土壤自然背景值为标准,Cu的超标率增加了将近3倍,表明Cu在土壤中已经产生了一定的积累。Hg与As的含量呈显著负相关（P ＜0.05）,Hg和Ni、Cr与Cu之间呈显著正相关（P ＜ 0.05）,其它元素之间的相关性未达到显著水平。推测个别元素超标的情况仅属于点源污染,不会引起复合污染。青岛市3个花生优势产区莱西、平度、即墨土壤重金属的环境质量均属于1级,适宜作为无公害花生的生产基地。     

云南部分古茶园土壤重金属元素的监测与评价

对10个云南古茶园(种植年限为百年、数百年甚至千年)50个土壤样品的金属元素As、Pb、Cd、Hg、Cr、Cu、Fe、Mn、Zn和Se的含量进行测定,研究其分布特征和变化规律,并用污染指数方法评价其土壤环境质量.结果表明:云南古茶园土壤Fe和Mn含量较高,Se含量较低,Pb(10.7～33.5 mg/kg),Hg(0.030～0.148 mg/kg),Cd (0.033～0.120 mg/kg),Zn (21.4～87.3 mg/kg)均达到国家土壤环境质量一级标准;Cr(15.4～98.5 mg/kg),As(12.2～33.1 mg/kg),Cu(13.6～43.4 mg/kg)均达到国家土壤环境质量二级标准.根据土壤环境质量二级标准评价古茶园土壤重金属综合污染状况,所有古茶园综合污染指数小于0.7,表明古茶区土壤属于清洁水平,未受重金属污染,满足有机茶园环境条件,适合建设有机茶园.     

贵州某茶叶种植区土壤重金属含量及环境质量评价

以贵州某茶叶基地为研究对象,对土壤中重金属Pb、As、Cd、Cr、Cu的含量进行测定,并采用单因子污染指数法和内梅罗综合污染指数法对其污染程度进行评价。结果表明:Pb、As、Cd、Cr、Cu的含量均值均低于无公害茶园土壤环境质量限量标准,除Pb元素外,As、Cd、Cr、Cu的含量均值均低于贵州省土壤背景值;Pb的平均污染程度为轻污染,As、Cd、Cr、Cu的平均污染均为无污染水平;土壤重金属的综合污染指数Pn均值为0.94,整体处于清洁无污染程度,其整体环境质量通过适当调控适宜建立无公害绿色茶园。     

琼海市水稻土重金属污染现状及评价

在琼海市12个乡镇的典型土壤中采集21个混合土壤样本,并对各土壤样本中重金属元素Hg、Cd、Cr、Pb和As的含量进行测定,以了解琼海市水稻土重金属含量及污染现状。依据国家土壤环境质量二级标准,采用单项污染指数法以及内梅罗综合污染指数法评价土壤中重金属的污染程度。结果表明：琼海市水稻土各重金属元素的平均含量均小于二级标准值;表层土壤Pb和Hg、Pb和Cd、As和Cd、As和Pb之间存在显著相关性(P＜0.01);从单项污染指数来看,除了大路镇存在Cr元素轻度污染外,其他各乡镇均未受到重金属Hg、Cd、Cr、Pb和As的污染;从全市范围来看,仅有大路镇为警戒级程度,其他11个乡镇安全清洁,全市的综合污染指数仅为0.32,说明全市水稻土环境质量状况整体清洁,处于安全水平。     

三明市郊区农产品产地土壤环境质量评价

以三明市郊区茶园、耕地、果园及菜地4种不同农产品土壤为调查对象,通过分析土壤中重金属含量,采用单项质量指数与综合质量指数相结合的方法评价了不同土地利用下的土壤环境质量状况。结果表明,三明市郊区农产品基地土壤重金属的平均含量均低于"HJ332-2006"(食用农产品产地环境质量评价标准)规定的限值,单项污染指数和综合污染指数均小于0.7,综合评价均为1级,土壤环境质量属于清洁,适宜发展无公害农产品。同时发现,部分基地的土壤中重金属含量有超标现象,4种农产品产地均出现部分取样品Cd含量超标情况;茶园、水稻田、蔬菜地均出现部分样品Pb含量超标;水稻田、果园、蔬菜3种基地部分取样品Hg含量超标;茶叶产地、水果产地出现部分样品Cu含量超标。大部分取样点土壤重金属均高于福建省土壤重金属背景值,表明在监测点土壤中存地重金属污染风险。     

海南省万宁市水稻土重金属污染的初步研究

为调查万宁市水稻田土壤的重金属污染状况, 在该地区 12 个乡镇的典型土壤中采集了 19 个混合土壤样本, 并对各土壤样本中的重金属元素 Hg、 Cd、 Cr、 Pb 和 As 的含量进行了测定。 依据国家土壤环境质量二级标准, 用单项污染指数法和内梅罗综合污染指数法评价土壤重金属的污染程度。 结果表明： 各乡镇水稻土壤均未受到重金属 Hg、 Cd、 Cr、 Pb 和 As 的污染; 从全市范围来看, 综合污染指数仅为 0.22, 说明全市水稻土壤环境清洁, 处于安全水平。     

铜陵市老洲乡蔬菜基地重金属污染现状评价

以安徽省自然土壤背景值为参数,以国家土壤环境质量二级评价标准为依据,结合单污染指数和综合污染指数的计算,对铜陵市老洲乡蔬菜基地土壤重金属污染现状进行了评价。结果表明,土壤中5种重金属的平均含量均低于国家土壤重金属污染物二级标准,Hg、As和Cu的平均含量超过安徽省自然土壤背景值;但单项污染指标均未超过1．0,综合污染指数均在0．7以下,属于安全范围。     

依据EurepGAP标准评价海南省福山镇荔枝种植区环境质量主要指标

按照《EurepGAP综合农业保证通则》，对海南省澄迈县荔枝种植区4个监控区大气、农田土壤和农田灌溉水环境质量进行定点、定位监测分析。结果表明，海南省澄迈县荔枝种植区大气无污染，土壤和灌溉水中综合污染指数显示清洁或尚清洁水平，监测项目值均低于EurepGAP标准，未造成污染。海南省澄迈县荔枝种植区达到EurepGap农产品产地环境质量要求。     

On the Chemistry,Toxicology and Genetics of the Cyanobacterial Toxins,Microcystin, Nodularin,Saxitoxin and Cylindrospermopsin

The cyanobacteria or “blue-green algae”, as they are commonly termed, comprise a diverse group of oxygenic photosynthetic bacteria that inhabit a wide range of aquatic and terrestrial environments, and display incredible morphological diversity. Many aquatic, bloom-forming species of cyanobacteria are capable of producing biologically active secondary metabolites, which are highly toxic to humans and other animals. From a toxicological viewpoint, the cyanotoxins span four major classes: the neurotoxins, hepatotoxins, cytotoxins, and dermatoxins (irritant toxins). However, structurally they are quite diverse. Over the past decade, the biosynthesis pathways of the four major cyanotoxins: microcystin, nodularin, saxitoxin and cylindrospermopsin, have been genetically and biochemically elucidated. This review provides an overview of these biosynthesis pathways and additionally summarizes the chemistry and toxicology of these remarkable secondary metabolites.     

Structure Elucidation of New Acetylated Saponins,Lessoniosides A,B, C,D, and E,and Non-Acetylated Saponins,Lessoniosides F and G,from the Viscera of the Sea Cucumber Holothuria lessoni

Sea cucumbers produce numerous compounds with a wide range of chemical structural diversity. Among these, saponins are the most diverse and include sulfated, non-sulfated, acetylated and methylated congeners with different aglycone and sugar moieties. In this study, MALDI and ESI tandem mass spectrometry, in the positive ion mode, were used to elucidate the structure of new saponins extracted from the viscera of H. lessoni. Fragmentation of the aglycone provided structural information on the presence of the acetyl group. The presence of the O-acetyl group was confirmed by observing the mass transition of 60 u corresponding to the loss of a molecule of acetic acid. Ion fingerprints from the glycosidic cleavage provided information on the mass of the aglycone (core), and the sequence and type of monosaccharides that constitute the sugar moiety. The tandem mass spectra of the saponin precursor ions [M + Na]⁺ provided a wealth of detailed structural information on the glycosidic bond cleavages. As a result, and in conjunction with existing literature, we characterized the structure of five new acetylated saponins, Lessoniosides A–E, along with two non-acetylated saponins Lessoniosides F and G at m/z 1477.7, which are promising candidates for future drug development. The presented strategy allows a rapid, reliable and complete analysis of native saponins.     

Millets, Rice, Social Complexity, and the Spread of Agriculture to the Chengdu Plain and Southwest China

Southwest China played a pivotal role in the spread of agriculture across East and Southeast Asia. Both rice and millet were important in the spread of populations and the expansion of agriculture into this region. Recent finds in the mountainous peripheries of Sichuan Province show that the earliest inhabitants of this region practiced a combination of broomcorn and foxtail millet agriculture (ca 4000?C2500 BC). These crops are adapted to high altitude and arid environments, which facilitated their movement across this region and eventually into the Tibetan Plateau. At around 2700 BC, a combined system of rice and foxtail millet agriculture appears suddenly in sites of the Baodun culture on the Chengdu Plain. The use of this double cropping system provided advantages to the inhabitants of this region in both risk reduction and yield. I argue that this had important consequences for spurring population growth, facilitating expansion into new territories and the development of social complexity.     

Evaluation of the enzyme-amplified ELISA for the detection of potato viruses A,M, S,X, Y,and leafroll

Various parameters,e.g. types of microtiter plate for DAS-ELISA (double antibody sandwich-enzyme-linked immunosorbent assay), use of fresh or frozen amplifier solutions for enzyme-amplified-ELISA, and use of sodium diethyldithiocarbamate (NaDIECA) in sample buffer in cocktail-ELISA were evaluated for the detection of potato viruses A, M, S, X, Y and leafroll from potato foliage. Dynatech Immulon immunoplates provided higher readings for all viruses. Fresh amplifier solution in amplifed-ELISA was superior to frozen solutions. Amplified ELISA gave only marginal improvement in the sensitivity over the standard DAS-ELISA. Addition of NaDIECA in sample buffer did not improve the detection of viruses in DAS-, amplified-, or cocktail-ELISA. Cocktail-ELISA can reduce antigen incubation time to as short as 15 min for PVA, PVM and PVX; 1 hr for PVY and PLRV; and 2–4 hr for PVS using pre-coated plates. Although amplified-ELISA is slightly more sensitive than DAS-ELISA for certain potato viruses, it is not suitable for large-scale indexing of potato viruses in Seed Certification Laboratories, in view of the additional steps needed in carrying out this procedure.     

Gibberellins,inhibitors, and tuber formation in the potato,Solanum tuberosum

Endogenous gibberellins were measured in extracts of ‘Red Pontiac’ potato tubers sampled during tuber ontogeny. Stolons contained high levels of activity and developing tubers low activity, as indicated by elongation in the dwarf pea and maize mutant bioassays. However, dilution of the extracts of young tubers revealed that low gibberellin-like activity may have been due to the presence of an inhibitor. Based on co-chromatography this inhibitor was found not to be abscisic acid nor did abscisic acid induce tuber formation after treatment of the intact plant, treatment of the developing stolons or after addition to potato stolons grown in tissue culture medium.     

Temperature,cyanide, and oxygen effects on the respiration,chip color,sugars, and organic acids of stored tubers

The possibility that sugar accumulation of potatoes stored at low temperatures may be linked to activation of cyanide-resistant respiration (CRR) was investigated. After a lag period of several days, continuous HCN treatment stimulated CO₂ production of tubers stored in 20% O₂. At 1°C in 20% O₂, HCN treatment increased respiration over that effected by low temperature treatment. After several weeks of treatment, cyanide-stimulated CO₂ production was greater at 1°C than at 10°C. Sucrose and malate levels of HCN treated tubers were sometimes higher than those of the 10°C control tubers, but they were always lower than those of the 1°C control tubers. This indicated that CRR alone could not account for the sugar increases at 1°C. Storage in 2% O₂ blocked the increase in CO₂ production and changes in constituents associated with HCN treatments in 20% O₂. HCN treatment had no significant effect on chip color. The level of CRR was measured in freshly cut slices from Monona, Norchip, and Kennebec tubers previously stored at 10°, 5°, or 1°C for several months. Slices from tubers previously stored at 1°C had increased CRR, but there was no difference in CRR between the 5°C and 10°C treatments. Sugars accumulated at 5°C, again indicating that sugar accumulation in potatoes stored at low temperatures was at least partially independent of the activation of CRR.     

Influence of a non-copper algicide on the cyanobacterium, Nostoc spongiaeforme, and the green alga, Hydrodictyon reticulatum, in field and laboratory experiments

Cyanobacteria and algae grow in California rice fields where they form large mats that may smother seedlings or cause them to dislodge, resulting in reduced rice stand establishment and potential yield loss. The most troublesome species of cyanobacteria is Nostoc spongiaeforme. It is very difficult to control using currently accepted methods, i.e., aerial applications of copper sulfate. A non-copper algicide, the mono (N,N-dimethylalkylamine) salt of endothall has been suggested as an alternative method for controlling nuisance cyanobacterial and algal growths in California rice fields. The purpose of the experiments described here was to evaluate the effect of the mono (N,N-dimethylalkylamine) salt of endothall on growth of N. spongiaeforme and the green alga, Hydrodictyon reticulatum. In laboratory experiments, the mono (N,N-dimethylalkylamine) salt of endothall reduced N. spongiaeforme growth at 0.3 mg L^?1. This effect was removed when rice straw was added to the growth medium, indicating that the rice straw may have introduced bacteria capable of degrading the mono (N,N-dimethylalkylamine) salt of endothall. In outdoor experiments, which used rice field water containing decomposing rice straw, the mono (N,N-dimethylalkylamine) salt of endothall concentrations between 0 and 5 mg L^?1 had little effect on N. spongiaeforme. In contrast, H. reticulatum exhibited injury symptoms at 1 mg L^?1 or greater. However, H. reticulatum recovered by the end of the 7-day exposure. It is not clear how this algicide will be useful in the management of N. spongiaeforme or H. reticulatum in California rice fields.     

Indole Diterpenoids and Isocoumarin from the Fungus,Aspergillus flavus,Isolated from the Prawn,Penaeus vannamei

Two new indole-diterpenoids (1 and 2) and a new isocoumarin (3), along with the known β-aflatrem (4), paspalinine (5), leporin B (6), α-cyclopiazonic acid (7), iso-α-cyclopiazonic acid (8), ditryptophenaline (9), aflatoxin B₁ (10), 7-O-acetylkojic acid (11) and kojic acid (12), were isolated from the fermentation broth of the marine-derived fungus, Aspergillus flavus OUCMDZ-2205. The structures of Compounds 1–12 were elucidated by spectroscopic analyses, quantum ECD calculations and the chemical method. New Compound 1 exhibited antibacterial activity against Staphylococcus aureus with a MIC value of 20.5 μM. Both new Compounds 1 and 2 could arrest the A549 cell cycle in the S phase at a concentration of 10 μM. Compound 1 showed PKC-beta inhibition with an IC₅₀ value of 15.6 μM. In addition, the absolute configurations of the known compounds, 4–6 and leporin A (6a), were also determined for the first time.     

Sugars of the unfermented sap and the wine from the oil palm,Elaeis guinensis,tree

The sugar composition of the unfermented sap from oil palm (Elaeis guinensis) trees growing in the plantations of the Nigerian Institute for Oil Palm Research, Benin City, has been determined. While sucrose concentration ranges from 9.59 to 10.59% (w/v) in the pure unfermented sap, that of either glucose or fructose is much less than 1% (w/v) (0.13–0.73% w/v). Raffinose occurs in traces only (0.13–0.35 w/v). These results were derived from our improved methods which eliminate completely, or reduce to a bare minimum, fermentation of the sap during collection. The variation with time of storage of the individual sugars in the sap during fermentation to form palm wine reveals that, as sucrose steadily decreases, fructose reaches a peak at 1.51% (w/v) at the 9th hour, and thereafter declines, while glucose and raffinose remain continuously low; all sugars disappear beyond the 33rd hour. Concomittantly, pH decreases from pH 6.60 at zero time and stabilizes at pH 3.30 after 48 h, while titrable acidity increases continuously up until the 96th hour. These changes account for the variations in the quality of palm wine during storages.