柿属植物ISSR分析技术的建立

以部分柿属(Diospyros)植物为材料,对ISSR-PCR反应体系腗g2+、dNTPs、引物、模板DNA和Taq DNA聚合酶浓度,退火温度及扩增循环次数进行了探讨,确立了适合柿属植物ISSR分析技术体系在25 μL反应体系中,含1× Buffer,Mg2+2.0或2.5 mmol/L,dNTPs 0.2 mmol/L,引物0.6 μmol/L,Taq DNA聚合酶1U,甲酰胺2%,模板DNA 2.4 ng/μL;PCR扩增程序94℃变性3 min;94℃ 30 s,(Tm+2)℃(根据引物不同设定)45 s,72℃1.5 min,35个循环;72℃延伸7 min;2%琼脂糖电泳分离PCR产物.结果为柿属植物遗传多样性和分子系统学研究提供技术支持.     

正交设计优化玉米SSR—PCR反应体系的研究

为建立适宜玉米SSR—PCR的反应体系和扩增程序,利用正交设计L16（4^5）表,对反应体系的模板DNA、dNTPs、Primers、Taq DNA聚合酶的浓度进行4因素4水平优化筛选和扩增程序的优化,确立了最优反应体系和扩增程序。即在10μL体系中,模板DNA20ng,1×PCR buffer,dNTPs62．5pmol／μL,Primers0．25pmol／μL,Taq DNA polymerase0．5U。反应程序为：94℃预变性5min;94℃变性45S,60℃退火45S,72℃延伸1min,32个循环;72℃延伸5min,4℃保存。使用300对SSR引物对重组近交系的两亲本扩增,筛选出条带清晰,有差异的引物94对,用于基因连锁图谱构建和QTL定位。     

东兴金花茶SSR-PCR反应体系的优化及引物筛选

采用L16（45）正交设计试验对东兴金花茶SSR-PCR反应的五因素（Mg^2＋,dNTPs,引物,Taq酶和模板DNA浓度）四水平进行了优化试验,然后利用优化后的反应体系,将31对同属植物SSR引物（4对茶树,7对山茶和20对金花茶引物）运用于东兴金花茶材料上,筛选适宜东兴金花茶遗传分析的SSR引物。结果表明,东兴金花茶最佳反应体系（15μL）及扩增条件为：Mg^2＋1.50 mmol/L、dNTP 0.30 mmol/L、引物0.40μmol/L、Taq酶0.75 U、模板DNA 40.00 ng;最佳扩增程序为：94℃预变性5 min;94℃变性30 s,58℃退火30 s（因引物而异,该温度为引物CN10的退火温度）,72℃延伸40 s,共36个循环;72℃最后延伸10 min。山茶属的不同植物之间可以共享部分SSR引物信息,东兴金花茶获得了9对能扩增出条带清晰且具有多态性的引物,引物最适退货温度为54-60℃,观测杂合度（HO）和期望杂合度（HE）分别为0.433-1.000和0.391-0.932。本试验为下一步进行的东兴金花茶遗传多样性分析、遗传图谱的构建等研究奠定了基础。     

枣SRAP-PCR体系的正交优化研究

采用正交试验设计的方法,建立了枣SRAP分析的优化反应体系,即20µL反应体系中含有1×buffer,dNTP 200µmol/L、引物各30ng、MgCl2 2.5mmol/L、Taq酶1.0U和模板DNA 20ng。适宜的扩增条件为94℃预变性5min;94℃变性1min,33℃复性1min,72℃延伸1min,5个循环;94℃变性1min,53℃复性1min,72℃延伸1min,30个循环;最后72 ℃延伸5min。本研究建立的枣SRAP 体系重复性好,稳定性强。     

兰州百合DNA提取方法比较及RAPD体系的快速优化

以兰州百合鳞片和叶片为试材,采用改良CTAB法获得了高质量的基因组DNA。为优化兰州百合RAPD-PCR反应体系,利用正交试验设计,对兰州百合RAPD-PCR反应体系中的5种主要因素进行4水平共计16个组合设计,并选用3种反应程序,通过琼脂糖凝胶电泳结果分析,最终获得最佳反应体系为:20 uL反应体系中含30 ng模板DNA、0.5 μmol/L随机引物、0.2 mmol/L dNTPs、2.25 mmol/L MgCl2, 及1.5U Taq DNA聚合酶。最佳反应程序:94 ℃预变性4 min;94 ℃变性1 min,36 ℃退火1.5 min;72 ℃延伸2 min;35个循环;最后72 ℃延伸7 min。     

龙眼SCoT-PCR反应体系的优化

目标起始密码子多态（start condon tardeted polymorphism,SCoT）分子标记结合了ISSR标记和RAPD标记的优点,具有操作简单﹑成本低廉﹑多态性丰富﹑重复性好﹑引物设计简单且通用性良好等诸多优点。本实验以石硖龙眼的新鲜叶片为试材,采用单因素试验的方法分别研究模版、引物、rTaqDNA聚合酶、dNTPs、缓冲液（Mg2＋）及退火温度共6因素各8个水平对龙眼SCoT-PCR扩增结果的影响。结果表明：龙眼SCoT标记的20μL优化反应体系为：10×BufferⅡ（含Mg2＋）2.0μL、DNA模板30ng、引物浓度为30μmol/L、rTaqD-NA聚合酶用量为0.45U、dNTP浓度为4.0mmol/L。适宜的扩增程序为：94℃预变性4min;95℃变性50s,49.5℃退火40s,72℃复性2min,36个循环;最后72℃延伸10min。利用24个龙眼品种验证该反应体系,1.5%琼脂糖电泳检测结果显示,扩增产物在400-2200bp之间,不同品种间DNA谱带具有多态性,反应体系具有良好的稳定性和可重复性。     

荔枝SRAP—PCR反应体系的优化

SRAP（sequence-related amplified polymorphism）是基于基因的内含子和外显子区域进行检测的新型分子标记技术,具有多态性高、重复性好、易测序、便于克隆目标片段等特点,在荔枝（Litchi chinensis Sonn）中还没有相关的研究报道。为了建立适合荔枝的SRAP反应体系,对反应体系中的DNA模板、Mg^2＋、dNTP、引物、砌DNA聚合酶诸因子的用量进行了探索,确立了适合荔枝的SRAP反应体系为：在20μL反应体系中,模板DNA为40ng,Mg^2＋浓度2．5mmol／L,dNTP0．3mmol／L,引物5mmol／L,TaqDNA聚合酶1．0U。扩增程序为：94℃预变性3min,反应前5个循环在94℃1min、35℃1min、72℃1 min的条件下运行;随后的35个循环退火温度提高到50℃;最后72℃延伸10min。利用该反应体系对荔枝10个不同品系进行SRAP反应,用5％的变性聚丙烯酰胺凝胶电泳检测,结果显示：不同品系间DNA谱带多态性丰富。证实该体系稳定可靠,可以用于荔枝的分子标记研究。     

北方黑土土壤细菌16S rDNA扩增体系的优化

采用降落PCR方法扩增目的基因,设计两次正交试验对PCR反应体系中的各组分浓度进行筛选,同时对退火时间、延伸时间及循环次数进行摸索。结果表明,适合北方黑钙土土壤细菌16S rDNA扩增体系为:在25μl体系中,10×buffer2.5μl,DNA模板20ng,Mg2+2.5mmolL-1,dNTPs0.25mmolL-1,引物0.3μmolL-1,TaqDNA聚合酶1.5U。降落PCR扩增程序为:95℃,5min;95℃,45s;65~56℃,60s;72℃,90s;每两个循环降低1℃。95℃,45s;5.5℃,60s;72℃,90s;10个循环。最后72℃,10min。     

松毛虫DNA的提取及ISSR反应体系的建立

为摸索适宜松毛虫的ISSR体系，以油松毛虫为实验材料，研究了ISSR技术中PCR反应体系的主要成分对ISSR扩增结果的影响。对ISSR反应体系中Mg2+的浓度、引物浓度、dNTP浓度、Tag DNA聚合酶浓度、模板浓度以及退火温度进行了探索， 确立了适合松毛虫的ISSR反应体系为： 在25μL反应体系、Mg2+、引物和dNTP的最适浓度分别为2.5mmol.L-1、0.8μmolL-1、0.20mmol.L-1； 反应体系中Tag DNA聚合酶宜加入1.25Ｕ， 模板DNA应加入15～30ng；引物的最佳退火温度为45.9～52.4℃。并利用该反应体系对14个地区的5种松毛虫进行ISSR反应，用1.5％的琼脂糖凝胶电泳检测，谱带多态性丰富，清晰稳定，证实该体系稳定可靠。     

柿和君迁子SSR分析技术的建立

通过搜寻核酸数据库中柿属植物核苷酸序列,利用Sputnik程序查找微卫星,利用Primer Premier 5.0软件设计特异微卫星引物,并对影响PCR扩增的Mg2+、dNTPs、Taq DNA聚合酶、引物浓度,以及退火温度等因素进行优化.最终确定柿(Diospyroskaki)和君迁子(D.lotus)SSR-PCR最佳反应体系为模板DNA30 ng,Buffer1×,Mg2+2.5mmol/L,dNTPs0.2mmol/L,Taq DNA酶1 U,引物0.3 μmol/L,反应总体积20μL,退火温度50℃.     

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.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

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.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.