人参药材中人参皂苷的空间变异性及影响因子

为探究人参(Panax ginseng)皂苷含量的空间变异性及其影响因子,该研究以采自黑龙江、吉林、辽宁的28份六年生人参为研究对象,测定人参中9种单体皂苷含量,用单因素方差分析方法研究了人参皂苷含量的空间变异性。并用主成分分析、相关性分析和冗余分析法进行人参皂苷含量与气候因子、土壤因子的相关性分析。结果表明:吉林与辽宁人参的皂苷含量接近,且其含量高于黑龙江人参;影响皂苷含量的气候因子主要是降水,高温、日照时间是皂苷含量的限制因子;全氮、铁、钾、有机质、pH值、锰、磷、锌对人参化学品质的影响较大。     

南四湖区农田土壤有机质和微量元素空间分布特征及影响因素

基于地统计学和GIS技术相结合的方法,研究了南四湖区农田土壤有机质和微量元素的空间分布特征及其影响因素。结果表明,土壤有机质和微量元素均属中等变异程度,除硼符合正态分布外,其余土壤属性均符合对数正态分布。结构分析表明,除硼为纯块金效应外,土壤有机质和其它微量元素空间自相关性较强,其中结构性因素起主导作用。克里格插值结果表明,土壤有机质分布总体趋势为由北向南逐渐降低,锰、铜、锌分布总体趋势为中部高,南北两端低。影响因素分析表明,土壤类型、耕层质地、坡度、土地利用类型和地貌类型对土壤有机质均有显著影响。土壤类型主要是由于成土母质的差异影响土壤有机质的高低与分布,随质地由砂变粘、坡度由低变高,土壤有机质含量逐步升高,田间管理水平的差异是造成不同土地利用类型下土壤有机质含量差异的主要原因。微量元素中,除硼不受影响外,铁、锰、铜和锌与土壤类型、耕层质地、坡度、土地利用类型和地貌类型密切相关。     

土人参的化学成分与药理活性研究进展CSCD

土人参Talinum paniculatum(Jacq.)Gaertn.为马齿苋科一年生或多年生植物,主要分布在我国中南部地区,易于生长。土人参是一种重要的药食同源植物,具有解毒消痈,补中益气,通经下乳等功效。现代药理学研究发现土人参含有多糖、黄酮、植物甾醇、生物碱、三萜、有机酸等化学成分,具有抗氧化、消炎止痛、抗菌和保护心脏等药理活性。该文主要对土人参的化学成分、药理活性和安全性的研究进行综述,为土人参的进一步开发利用提供参考。     

北方土壤中Mn的形态及其与活性Mn的关系

用逐步连续分级浸提法研究了我国北方主要土壤中Mn的存在形态及其与活性Mn的关系.碱性土壤中Mn的形态分布特征为氧化锰态Mn>残留态Mn>有机质结合态Mn>无定形铁结合态Mn>晶形铁结合态Mn>代换态Mn,与酸性土壤的排列顺序明显不同.碱性上壤条件导致土壤中的Mn更多地向生物无效态转化,使得土壤的活性Mn主要以氧化锰态和代换态存在.     

速生薄口螨Histiostoma feronirum Dufour与人参坏死病

本文首次报告人参坏死病的传播介体为速生薄口螨。在速生薄口螨的消化道和唾液腺均查到大量的类菌原体 MLO,大小为90～1300nm,单位膜厚度为9～11nm。与在罹病人参的筛管细胞里观察到的类菌原体 MLO 相同。在子一代和子二代速生薄口螨体内仍可查到类菌原体。将带毒活螨或螨液接种健株人参,健株人参发病。使用三氯杀螨(虫风)拌土,对人参坏死病有显著的抑制作用。初步认为速生薄口螨是人参坏死病的传播介体。     

用葫芦藓证实叶绿体是光合作用的重要细胞器

绿色植物的光合作用主要是在叶绿体中进行的,叶绿体是光合作用的重要细胞器。葫芦藓（ＦｕｎａｒｉａｈｙｇｒｏｍｅｔｒｉｃａＨｅｄｗ．）为小型土生藓类,多生于有机质丰富含氮素较多的湿土。我国南北各地均有分布,系植物学教学中苔藓植物门藓纲常见的代表植物;盆栽...     

土壤肥力对板栗枝干病害的影响

通过对土壤肥力与板栗枝干病害关系的研究表明,在土壤物理因素中,土壤类型以粘土、石砾土的栗园发病较重,壤土、沙壤土、黄棕壤的栗园发病较轻;土壤容重与感病指数呈正相关;土层厚度与感病指数呈负相关。在土壤化学因素中,有机质、速效磷与病情呈负相关;pH值、全氮和钾含量与病情关系不显著,并通过对土壤肥力因素与病情关系的逐步回归分析,筛选出土层厚度、土壤容重、粘性土、有机质和速效磷5个因素对病情贡献较大。以此建立了病情预测的回归模型,根据这一模型,可以预测研究范围内的任一给定条件下病害可能发生的水平,该研究将为今后的板栗生产和管理提供指导。     

白浆土—植物系统营养物质转化机制及其有效性研究Ⅱ.白浆土无机 …

采用室内培养和微区试验研究表明,施入白浆土中无机磷在短时间内主要向Ｆｅ－Ｐ和Ａｌ－Ｐ转变,较长时间后,Ａｌ－Ｐ向Ｆｅ－Ｐ转化,Ｃａ－Ｐ变化较弱,土壤中无机磷形态转化与白浆土本身的土壤属性具有密切着关系,施用有机肥改变了土壤中无机磷形态的转化过程,其与土壤中的铁、铝氧化物反应形成的“Ａｌ－有机质－Ｐ”和“Ｆｅ－有机质－Ｐ”是作物较易利用的有效Ｐ源。     

应用11371复合剂防治人参锈腐病的研究

人参锈腐病是栽培参的主要病害,发病率一般在60—80％,对栽培参的损失很大。由于该病是土传病害,而且致病菌复杂,多年来尚无较好的防治方法。本文介绍了使用抗生素11371为主的复合药剂防治人参锈腐病的情况;几年来田间防效稳定在45％以上,最高防效可达70％,并且用药当年可增产15％左右。     

人参皂苷与生态因子的相关性

环境条件影响中药材活性成分的形成和积累.利用各种数学统计分析方法探讨影响人参皂苷积累的生态因子,提高人参品质.人参样品采自人参道地产区(主产区)吉林、辽宁、黑龙江三省5年生栽培人参,同时采集采样点处的土壤样品.超高效液相(UPLC)色谱法分析了不同产区9种人参皂苷(Rg1、Re、Rf、Rg2、Rb1、Rc、Rb2、Rb3、Rd)的含量;利用“中药材产地适宜性分析地理信息系统”的生态因子空间数据库,获得采样区包括温度、水分、光照等10个生态因子数据;按土壤理化性质常规方法测定土壤样品中的有效硼、有效铁等微量元素和速效氮、速效钾等有效养分.对人参有效成分含量与土壤养分进行典型相关性分析发现,土壤中的有效硼、有效铁、速效氮与人参皂苷含量呈显著正相关,即适当提高土壤中有效硼、有效铁和速效氮的含量可以促进人参皂苷成分的积累,土壤水分与所测人参皂苷含量(Rb3除外)呈显著正相关,速效磷(P)、pH、速效锌(Zn)与各人参皂苷含量呈弱相关;人参皂苷与气候因子相关分析表明,温度(年活动积温、年平均气温、7月最高气温、7月平均气温、1月最低气温、1月平均气温)与人参皂苷含量呈显著负相关,其中与药典中人参含量测定项下的人参皂苷Rg1、Re、Rb1负相关尤为显著(r＞0.6),说明在一定温度范围内,人参皂苷是随着温度的降低而升高的,即适当低温有利于人参皂苷有效成分的积累;海拔与人参皂苷Rc、Rb2、Rb3含量呈显著正相关(r＞0.6),即相对较高的海拔可以促进这3种成分的积累;而年均降水量、年相对湿度和年均日照时数与人参皂苷相关不显著.通过主成分分析(PCA)、典型相关分析、排序等统计方法,考察不同产地样品中人参皂苷含量与生态因子间的相关性,研究结果揭示了温度在人参的主要活性成分-皂苷类形成中起决定性作用,在一定的温度范围内,温度越低越有利于人参皂苷的积累;阐明了土壤中的有效硼、有效铁、速效氮与人参皂苷含量成正相关.研究结果提示在人参实践生产中可以通过适当低温处理,增施硼、铁、氮肥等农艺措施来调控人参皂苷含量.     

有机物料对滨海盐渍土重金属根际效应的影响Ⅱ.土壤内源铁形态分布

研究了排水条件下施用腐熟有机物料、种稻改良滨海盐渍土内源铁形态分布．结果表明,单淹水利于土中无定形氧化铁、络合态铁、有效态铁以及氧化铁活化度升高,并且络合态铁与有效态铁升高程度,低盐土壤显著;晶形氧化铁变化不明显,土中可能存在其它形态铁向晶形氧化铁转化．种稻不施有机物料,根际络合态铁和有效态铁富集;无定形氧化铁和晶形氧化铁亏缺．根际氧化铁活化度稍低于非根际．增施有机物料利于两种盐渍土根际内外铁形态向络合态铁和无定形氧化铁转化;有效态铁和氧化铁活化度提高,低盐土壤根际较明显     

Organic matter mineralization with the reduction of ferric iron: A review

A review of the literature indicates that numerous microorganisms can reduce ferric iron during the metabolism of organic matter. In most cases, the reduction of ferric iron appears to be enzymatically catalyzed and, in some instances, may be coupled to an electron transport chain that could generate ATP. However, the physiology and biochemistry of ferric iron reduction are poorly understood. In pure culture, ferric iron‐reducing organisms metabolize fermentable substrates, such as glucose, primarily to typical fermentation products, and transfer only a minor portion of the electron equivalents in the fermentable substrates to ferric iron. However, fermentation products, especially hydrogen and acetate, may be important electron donors for ferric iron reduction in natural environments. The ability of some organisms to couple the oxidation of fermentation products to the reduction of ferric iron means that it is possible for a food chain of iron‐reducing organisms to completely mineralize nonrecalcitrant organic matter with ferric iron as the sole electron acceptor. The rate and extent of ferric iron reduction depend on the forms of ferric iron that are available. Most of the ferric iron in sediments is resistant to microbial reduction. Ferric iron‐reducing organisms can exclude sulfate reduction and methane production from the zone of ferric iron reduction in sediments by outcompeting sulfate‐reducing and methanogenic food chains for organic matter when ferric iron is available as amorphic ferric oxyhydroxide. There are few quantitative estimates of the rates of ferric iron reduction in natural environments, but there is evidence that ferric iron reduction can be an important pathway for organic matter decomposition in some environments. There is a strong need for further study on all aspects of microbial reduction of ferric iron.     

Reduction of ferric green rust by Shewanella putrefaciens

AIMS: To reduce carbonated ferric green rust (GR*) using an iron respiring bacterium and obtain its reduced homologue, the mixed Fe(II)-Fe(III) carbonated green rust (GR). METHODS AND RESULTS: The GR* was chemically synthesized by oxidation of the GR and was incubated with Shewanella putrefaciens cells at a defined [Fe(III)]/[cell] ratio. Sodium methanoate served as the sole electron donor. The GR* was quickly transformed in GR (iron reducing rate = 8.7 mmol l(-1) h(-1)). CONCLUSIONS: Ferric green rust is available for S. putrefaciens respiration as an electron acceptor. The reversibility of the GR redox state can be driven by bacterial activity. SIGNIFICANCE AND IMPACT OF THE STUDY: This work suggests that GRs would act as an electronic balance in presence of bacteria. It provides also new perspectives for using iron reducing bacterial activity to regenerate the reactive form of GR during soil or water decontamination processes.     

蚯蚓和铁处理对苹果根铁营养影响

试验于2007～2009年在河北省永年县曹庄村和中国农业大学曲周实验站进行。在苹果树根际用不同价态的2500、5000、10000、20000mg/kg的铁处理玉米秸秆后接种蚯蚓,研究蚯蚓和铁对苹果根系生长、蚯蚓对铁的富集转移及根质外体铁的影响。结果表明:蚯蚓对铁有很大的富集量,在20000mg/kg(试验所用最高浓度)二价铁和三价铁处理的秸秆中可以成活并把秸秆转化为蚯蚓粪,促进根系生长,提高根的质外体铁含量,蚯蚓对二价铁的适应性高于三价铁。蚯蚓可将有机物料中的铁转移到果树根系内,5000mg/kg铁处理增加蚯蚓体内Fe2+含量和根质外体铁含量效果最好,蚯蚓、蚯蚓粪和根中的全铁含量随铁处理浓度的增加而增加。铁显著促进果树根系生长,没有用铁处理过的秸秆接种蚯蚓诱导的新根量明显少于用铁处理的,两种不同价态的铁都是以5000mg/kg的新根量最多。蚯蚓显著促进根系生长,没有接种蚯蚓的处理新根量显著少于接种蚯蚓的处理。     

Microbial Communities Involved in Fe Reduction and Mobility During Soil Organic Matter (SOM) Mineralization in Two Contrasted Paddy Soils

Lowland rice fields of West Africa (Ivory Coast) and South Asia (Thailand) are affected by ferrous toxicity or salinity, respectively, and their soil waters contain large amounts of ferrous iron, depending on reducing irrigation condition and suggesting occurrence of bacterial reducing processes. To determine the involvement, dynamic and activities of bacterial communities in Fe(III) reduction and mobilization during anaerobic degradation and mineralization of soil organic matter (SOM), different experiments and analyses have been performed. Results demonstrated that the utilization of SOM as sole carbon, nutrient and energy sources favored the presence of large bacterial communities: facultative anaerobic and anaerobic bacteria, Fe(III)-reducing bacteria (FeRB) (fermentative and Fe respiring), sulfate reducing bacteria (SRB) which are involved in carbon, nitrogen, iron and sulfur cycling. The larger functional diversity is observed in the Ivory Coast paddy soils containing larger amounts of organic matter and sulfur compounds. These communities contained complementary populations (chemoorganotrophic, chemolitotrophic, aerobic, facultative anaerobic and anaerobic) that can be active at different steps of iron solubilization with simultaneous organic matter mineralization. Our results indicate that the pH controlled by bacterial activity, the nature much more than the content of organic matter, and consequently the structure and activity of bacterial communities influence significantly the availability and dynamic of iron in paddy fields which affect the soil quality.     

Influence of carbon sources and electron shuttles on ferric iron reduction by <Emphasis Type="Italic">Cellulomonas</Emphasis> sp. strain ES6

Microbially reduced iron minerals can reductively transform a variety of contaminants including heavy metals, radionuclides, chlorinated aliphatics, and nitroaromatics. A number of Cellulomonas spp. strains, including strain ES6, isolated from aquifer samples obtained at the U.S. Department of Energy’s Hanford site in Washington, have been shown to be capable of reducing Cr(VI), TNT, natural organic matter, and soluble ferric iron [Fe(III)]. This research investigated the ability of Cellulomonas sp. strain ES6 to reduce solid phase and dissolved Fe(III) utilizing different carbon sources and various electron shuttling compounds. Results suggest that Fe(III) reduction by and growth of strain ES6 was dependent upon the type of electron donor, the form of iron present, and the presence of synthetic or natural organic matter, such as anthraquinone-2,6-disulfonate (AQDS) or humic substances. This research suggests that Cellulomonas sp. strain ES6 could play a significant role in metal reduction in the Hanford subsurface and that the choice of carbon source and organic matter addition can allow for independent control of growth and iron reduction activity.     

湿地植物根表的铁锰氧化物膜

湿地植物根系具有泌氧能力 ,使其根表及根际微环境呈氧化状态。因而 ,土壤溶液中一些还原性物质被氧化 ,如 Fe2 ,Mn2 ,形成的氧化物呈红色或红棕色胶膜状包裹在根表 ,称为铁锰氧化物膜。铁锰氧化物膜及其根际微环境是湿地植物根系吸收养分和污染物的门户 ,势必会影响这些物质的吸收。主要综述了铁锰氧化物膜的形成和组成 ,以及根表形成的氧化物膜的生态效应 ,也就是氧化物胶膜对植物根系吸收外部介质中的养分及污染物质——重金属离子的影响     

Organic Matter Mineralization with Reduction of Ferric Iron in Anaerobic Sediments

The potential for ferric iron reduction with fermentable substrates, fermentation products, and complex organic matter as electron donors was investigated with sediments from freshwater and brackish water sites in the Potomac River Estuary. In enrichments with glucose and hematite, iron reduction was a minor pathway for electron flow, and fermentation products accumulated. The substitution of amorphous ferric oxyhydroxide for hematite in glucose enrichments increased iron reduction 50-fold because the fermentation products could also be metabolized with concomitant iron reduction. Acetate, hydrogen, propionate, butyrate, ethanol, methanol, and trimethylamine stimulated the reduction of amorphous ferric oxyhydroxide in enrichments inoculated with sediments but not in uninoculated or heat-killed controls. The addition of ferric iron inhibited methane production in sediments. The degree of inhibition of methane production by various forms of ferric iron was related to the effectiveness of these ferric compounds as electron acceptors for the metabolism of acetate. The addition of acetate or hydrogen relieved the inhibition of methane production by ferric iron. The decrease of electron equivalents proceeding to methane in sediments supplemented with amorphous ferric oxyhydroxides was compensated for by a corresponding increase of electron equivalents in ferrous iron. These results indicate that iron reduction can outcompete methanogenic food chains for sediment organic matter. Thus, when amorphous ferric oxyhydroxides are available in anaerobic sediments, the transfer of electrons from organic matter to ferric iron can be a major pathway for organic matter decomposition.     

Characterization of Phloem iron and its possible role in the regulation of fe-efficiency reactions

`Fe-efficiency reactions' are induced in the roots of dicotyledonous plants as a response to Fe deficiency. The role of phloem Fe in the regulation of these reactions was investigated. Iron travels in the phloem of Ricinus communis L. as a complex with an estimated molecular weight of 2400, as determined by gel exclusion chromatography. The complex is predominantly in the ferric form, but because of the presence of reducing compounds in the phloem sap, there must be a fast turnover in situ between ferric and ferrous (k ≈ 1 min⁻¹). Iron concentrations in R. communis phloem were determined colorimetrically or after addition of ⁵⁹Fe to the nutrient solution. The iron content of the phloem in Fe-deficient plants was lower (7 micromolar) than in Fe-sufficient plants (20 micromolar). Administration of Fe-EDTA to leaves of Phaseolus vulgaris L. increased the iron content of the roots within 2 days, and decreased proton extrusion and ferric chelate reduction. The increase in iron content of the roots was about the same as the difference between iron contents of roots grown on two iron levels with a concomitantly different expression of Fe-efficiency reactions. We conclude that the iron content of the leaves is reflected by the iron content of the phloem sap, and that the capacity of the phloem to carry iron to the roots is sufficient to influence the development of Fe-efficiency reactions. This does not preclude other ways for the shoot to influence these reactions.