高压微射流法制备白藜芦醇纳米脂质体

为提高白藜芦醇生物利用率与缓释作用,采用高压微射流法制备白藜芦醇纳米脂质体,以纳米脂质体包封率为评价指标,在单因素试验的基础上,通过二次旋转回归试验设计确定最佳制备工艺.结果表明,最佳制备工艺为卵磷脂/VE=10∶1,卵磷脂/白藜芦醇=11.6∶1,卵磷脂/胆固醇=10.5∶1,微射流压力18 366 PSI,循环次数3次.在此条件下制得白藜芦醇纳米脂质体的包封率为87.74％±1.01％,平均粒径为78.31nm±1.37nm,Zeta电位为-55.5 mV.该方法制得的白藜芦醇纳米脂质体包封率高、粒径小、分布范围窄,且体系稳定.该研究为白藜芦醇新剂型的开发及利用提供理论依据和实际指导.     

花生根、茎中白藜芦醇含量影响因素

为了获得含白藜芦醇较多的花生根、茎作为提取白藜芦醇的原料。该文考察了华东不同地区、不同品种、不同采收时间以及采后存放、提取环境对花生根、茎中的白藜芦醇含量的影响。结果表明:白藜芦醇富集在花生根表皮,木质部含量较少;不同生长环境、不同品种对花生中白藜芦醇的含量影响较大;同一品种,采收时间越晚,白藜芦醇含量越高。采收后的花生根霉变会提高其中的白藜芦醇含量;花生中白藜芦醇在酸性条件下较为稳定,而碱性条件下易变性。采用合适品种的晚收花生根在酸性条件下提取可得到白藜芦醇含量较高的原料。     

花生植株白藜芦醇提取工艺优化

为了提高花生的综合利用价值,开发天然白藜芦醇新原料,对花生中的白藜芦醇提取工艺进行了研究。通过对花生叶、茎、根和壳中白藜芦醇含量的比较,选出含量最高的花生根为提取原料,并从5种提取方法中选出纤维素酶法作为花生根白藜芦醇的提取方法。通过单因素试验和正交试验对酶法提取花生根白藜芦醇酶解工艺进行了优化。结果表明:最佳的酶解条件为酶用量为1.6mg/g,酶解温度为45℃,酶解pH值为4.5,反应时间为60min,底物浓度为15%,在此条件下白藜芦醇的提取率是传统提取工艺的2倍。     

T7RNAP基因的克隆及其质体定位表达载体的构建

为在番茄成熟果实组织中建立T7/T7RNAP质体转基因特异与高效表达系统,本文克隆了原核T7RNAP基因,在添加上质体定位信号肽编码序列后,由番茄果实成熟特异表达启动子PDS和Tnos终止子控制,构成了含有PDS-ptT7RNAP-Tnos基因表达盒的植物基因双元表达载体。该研究为在番茄质体工程中控制外源质体转基因在番茄成熟果实成熟组织中定点表达奠定了基础。     

水分胁迫对葡萄果实白藜芦醇合成相关基因表达的影响

为探究水分胁迫对葡萄果实白藜芦醇合成的影响,本研究以赤霞珠为试验材料,对其进行不同程度水分胁迫处理,测定葡萄果实白藜芦醇含量及白藜芦醇生物合成相关基因表达量。结果表明,葡萄果实进入转色期,PAL、4CL、STS基因随白藜芦醇合成而大量表达;不同水分胁迫处理均能增加葡萄果实白藜芦醇含量,同时提高白藜芦醇合成相关基因的表达量,不同水分胁迫处理间存在差异;水分胁迫对果实转色前期和后期PAL、STS基因表达的促进作用最为显著,但水分胁迫显著降低了CHS基因的表达量。相关性分析表明,白藜芦醇含量与PAL、STS基因的表达量呈显著正相关,表明水分胁迫主要通过诱导PAL、STS基因表达来增加果实白藜芦醇含量。本研究结果为进一步阐明葡萄白藜芦醇合成调控机制奠定了理论基础。     

利用甘薯质体同源片段构建多顺反子表达载体

本研究利用质体基因组的进化保守性，根据烟草质体基因组全序列设计引物，从甘薯（lpomoea batatas L．）质体基因组中克隆了两个相邻的功能基因rbcL（GenBank登录号为AY942199）和HaccD（GenBank登录号为AY942200），以此作为定点整合外源基因的同源重组片段。选用水稻质体基因组强启动子prm及psbA3’非翻译区调控选择标记基因aadA和报告基因gfp，构建多顺反子表达盒prm—aadA-gfp-psbA-3＇，之后将表达盒克隆进甘薯质体同源片段中，获得甘薯质体多顺反子定点整合表达载体pSAG，酶切鉴定结果表明所构建的载体符合预期设计。这为后期甘薯质体转化体系的建立和通过质体基因工程手段将更多目的基因导入甘薯进行遗传改良奠定了基础。     

不同钾肥组合对烤烟质体色素及降解产物的影响

采用田间试验,以普通钾肥为对照,研究了缓释钾肥及其与普通钾肥、黄腐酸钾的配施对烤后烟叶质体色素及其降解产物的影响.结果表明:T1(普通钾肥)和T2(缓释钾肥)均不利于降低烤后烟叶叶绿素含量,T2处理两种等级烟叶质体色素降解物质总量均低于T1处理,而T3处理(普通钾肥+缓释钾肥)显著降低了两种等级烟叶叶绿素含量,提高了中部叶质体色素降解物质总量,却降低了上部叶质体色素降解物质总量和类胡萝卜素含量;T4处理(普通钾肥+缓释钾肥+黄腐酸钾)能降低两种等级烟叶叶绿素含量、提高上部叶类胡萝卜素含量,其上部叶质体色素降解物质总量高于其他各处理,中部叶质体色素降解物质总量仅低于T3处理,此外上部和中部叶中分别有12种和8种类胡萝卜素降解产物含量高于其他各处理.故综合看,T4是最优的施钾处理.     

农杆菌VirD2蛋白的定位特异性改造

农杆菌(Agrobacterium tumefaciens)VirD2蛋白具有与单链T-DNA(ssT-DNA)共价结合并将其转运至植物细胞核,将外源基因高效整合进核基因组的功能;如果将该蛋白改定位于质体,则有可能利用其将外源基因携带进质体,建立质体转化新方法.本研究对VirD2蛋白的定位信号进行了改造,采用重叠延伸PCR突变技术对Vir2的N端核定位信号(NLS)编码序列进行点突变,对C端编码序列实施缺失突变,并在合成的突变VirD2(mVirD2)基因3’端连接上增强绿色荧光蛋白(eGFP)报告基因,在其5’端加上或不加源自拟南芥(A rabidopsis thaliana)冷调节基因(AtCOR15A)的质体定位信号肽编码序列,分别构成pt-mVirD2-eGFP和mVirD2-eGFP嵌合基因,由CaMV 35 S启动子控制,经农杆菌介导整合进烟草(ic otiana tab ac um)核基因组.荧光检验显示,mVirD2带质体定位信号时绿色荧光集中于叶绿体,mVirD2不带质体定位信号时绿色荧光弥散在细胞质中,且两者的细胞核均无荧光,表明pt-mVirD2-eGFP嵌合基因表达的蛋白具有质体定位特性,并失去了核定位能力.该结果为今后探讨利用pt-mVirD2融合蛋白将外源DNA主动定向牵引进质体,实现质体高效转化研究提供基础资料.     

RS基因转化胡萝卜及高白藜芦醇转基因胡萝卜株系筛选

摘要：白藜芦醇是具有抗病及多种保健功能的芪类次生代谢物,胡萝卜则是富含β胡萝卜素等多种营养成分的重要蔬菜。本研究着眼于创建具有白藜芦醇保健功能的胡萝卜新种质资源，在对葡萄白藜芦醇合成酶（Resveratrol synthase 简称RS）基因针对在胡萝卜中表达的密码子优化基础上构建无潮霉素抗性基因的转化载体pCB－RS－hyg-，应用农杆菌介导遗传转化方法将pCB和pCB－RS－hyg-共转化到胡萝卜并获得再生植株。经过T0、T1和T2代的逐代筛选，获得2个白藜芦醇含量较高的转基因胡萝卜株系，为进一步开发利用以及相关代谢途径的分子生物学研究奠定了重要基础。     

钙对苹果果实发育及果肉细胞超微结构的影响

以"红富士"苹果果实为试材,从盛花后10d开始,分3次向果实中引入CaCl2及EGTA,研究了钙对果实细胞超微结构和果实生长的影响。结果表明,钙处理使果实细胞细胞壁、质体等区域的电子密度增大,质体上的嗜锇颗粒大而清晰;钙的缺乏造成细胞壁扭曲、断裂等现象,使质体结构异常。钙处理抑制了果实生长。花后10～20d钙缺乏,促使果实横径发育,之后缺乏,对果实横径生长起到抑制作用。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

In-situ enrichment and analysis of atrazine-degrading microbial communities using atrazine-containing porous beads

We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg⁻¹ buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg⁻¹ in conditioned and control soil, respectively. The results demonstrate that BioSep^® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.