EMS离体诱变及抗草莓灰霉病愈伤组织的筛选

试验用甲基磺酸乙酯（EMS）处理草莓愈伤组织后通过草莓灰霉病病原毒素（Toxin）离体筛选获得抗病愈伤组织并诱导成苗。EMS诱变处理‘幸香’草莓离体叶片产生的愈伤组织,用经毒力检测的草莓灰霉菌毒素粗提液进行离体筛选,通过在愈伤组织继代培养中附加不同浓度毒素粗提液,以确定适宜的抗病选择压,获得抗灰霉病突变体材料。结果表明,将愈伤组织直接进行EMS处理的成活率高于将愈伤组织切割成小块继代培养再经EMS处理的愈伤组织;且0.2% EMS处理1h为最适剂量。在含80%毒素粗提液的培养基培养10 d为抗性筛选的适宜选择压。诱变处理后的867块愈伤组织,在经不连续二次筛选后有195块成活,成活率22.5%,其中有82块再生出了不定芽,再生率为42.1%。不定芽经生根后移栽至田间进一步进行抗性鉴定。     

EMS诱发草莓不同组培材料的耐盐性变异

以全明星草莓花药诱导的愈伤组织以及组培苗叶片为试验材料,用化学诱变剂甲基磺酸乙酯(EMS)进行诱变处理。结果表明,愈伤组织诱变处理的适宜浓度与时间组合为0.1%+1.5h和0.2%+1.0h,而(0.2%~0.4%)+(1.0~2.0h)可作为离体叶片诱变处理的适宜浓度和时间范围。与离体叶片诱变相比,草莓花药的愈伤组织对诱变剂EMS更为敏感。通过对再生植株的耐盐性进行比较发现,愈伤组织诱变筛选植株的盐害率和盐害指数低于离体叶片诱变筛选植株,说明愈伤组织较组培苗叶片更适于作为草莓耐盐诱变育种的起始材料。     

垂吊型矮牵牛叶片培养不定芽发生和微繁研究

以垂吊型矮牵牛叶片为材料 ,建立了垂吊型矮牵牛叶片高效不定芽发生、植株再生和微繁的技术体系。研究了不同激素及其组合对叶片不定芽发生、壮苗和生根的效应。结果显示 ,MS +BA 2mg L +NAA 0 1mg L是叶片不定芽发生的适宜培养基 ;MS +BA 0 5mg L +IBA0 1mg L +GA 0 5mg L是不定芽形成壮苗的适宜培养基 ;MS +IAA 0 1mg L是壮苗生根的适宜培养基 ;草炭珍珠岩基质是生根苗移栽的适宜基质     

EMS诱导太子参抗性突变体及分子检测

为创建太子参突变体库及创造太子参抗叶斑病新种质,用甲基磺酸乙酯(EMS)处理太子参愈伤组织后通过叶斑病粗毒素离体胁迫培养筛选抗病突变体,以愈伤组织0%相对生长量为指标,筛选抗病突变体的粗毒素临界致死浓度选择压,以愈伤组织在粗毒素培养基上50%存活率为指标,筛选EMS半致死处理组合。结果表明:25%粗毒素液培养20 d的处理组合可作为抗性突变体筛选的选择压;0.8%EMS处理2 h,0.8%EMS处理3 h和1%EMS处理2 h,可作为筛选突变体的EMS半致死组合。经EMS处理的愈伤组织提高了在叶斑病粗毒素液临界致死浓度中的存活率。50条RAPD引物PCR检测结果表明,突变体DNA序列发生了变异。突变体苗经田间鉴定,抗性评价为高抗。本研究为建立太子参EMS离体诱变定向改良性状技术体系奠定基础。     

农杆菌介导的洋桔梗遗传转化体系的建立

以洋桔梗叶片为外植体,建立了植株再生体系,并在此基础上,用根癌农杆菌介导法,研究了影响洋桔梗转化的若干因素。结果表明,诱导最佳培养基为MS+6-BA 1.0mg/L+NAA 0.15mg/L,不定芽诱导率达74.5%;不定芽生根培养基为1/2MS+IBA 0.5 mg/L,生根率达90%。不定芽分化阶段和生根阶段的Km筛选浓度分别为45mg/L和15mg/L;根癌农杆菌菌液浓度OD600值为0.6,侵染时间10min,共培养时间3d,有利于抗性芽的产生。Km筛选得到的抗性植株经过PCR和Southern检测表明,八氢番茄红素合成酶基因(PSY)已经整合到洋桔梗基因组中。     

蝴蝶兰类圆球茎的化学诱变试验

用不同浓度的甲基磺酸乙酯(EMS)和叠氮化钠(NaN3)对蝴蝶兰类圆球茎(PLB)作不同时间处理。结果显示:EMS和NaN3均可使部分PLB白化或褐化并逐渐致死。0.4%EMS接近PLB半致死剂量。PLB切片观察发现:用EMS和NaN3处理均可使细胞体积增大,细胞形状改变,细胞质浓缩。较高浓度NaN3处理的PLB细胞中出现晶体物质、双核、畸形核和核仁丢失等现象。较高浓度EMS处理的PLB细胞中出现微核、畸形核、多核、核破裂和核仁丢失等现象。同浓度的同种诱变剂随处理时间的增加材料的变异程度有增大趋势,但不很显著。EMS比NaN3的诱变处理效果好。0.5%EMS可作为创造蝴蝶兰PLB突变体的参考浓度。     

观赏羽衣甘蓝高频再生体系的建立

观赏羽衣甘蓝是一种赏食兼用的耐冻优良景观植物。为了通过基因工程手段赋予其抗虫性,并进一步提高其低温耐受性,获得新的抗性种质,本研究以优良育种品系为试材,详细探讨了影响离体培养不定芽再生的因素,建立了高效再生体系。以8份不同类型羽衣甘蓝基因型的带柄子叶、子叶、下胚轴为外植体,研究了不同基因型、不同外植体、不同的培养基激素浓度配比及添加AgNO3对不定芽诱导的影响。结果表明:无论基因型及使用的培养基,带柄子叶均为最佳外植体;不同的基因型、不同外植体其最佳的芽诱导培养基不同;筛选出两份材料,其带柄子叶分别在L6(MS+6-BA1.0mg/L+NAA0.1mg/L)及L3(MS+6-BA1.5mg/L)培养基中不定芽诱导率为100%,下胚轴诱导率最高也能达88.33%;培养基中添加4mg/L AgNO3不利于羽衣甘蓝的不定芽诱导;再生株生根以MS+NAA0.1mg/L效果好,生根率可达100%。     

多年生黑麦草EMS诱变与耐旱性评价

为构建多年生黑麦草突变体库,本研究采用甲基磺酸乙酯(EMS)对多年生黑麦草品种‘首相’种子进行诱变处理,设置6个诱变浓度(0%、0.4%、0.8%、1.2%、1.6%和2.0%)和3个处理时间(6、12、24 h),分析诱变后种子萌发、幼苗生长及耐旱变异株主要抗旱生理指标的变化。结果表明,1.6%EMS处理12 h与0.8%EMS处理24 h的种子发芽率均接近50%,综合分析结果表明,0.8%EMS处理24 h可作为适宜诱变组合。通过对诱变材料进行抗旱性筛选,共获得15株耐旱变异株,基于丙二醛、脯氨酸、可溶性糖含量、抗氧化酶活性等抗旱生理指标的综合评价表明,变异株B9、B10、B12在干旱胁迫下抗旱性较强,说明EMS诱变可以诱发抗旱变异体。本研究结果为多年生黑麦草的EMS诱变及耐旱育种提供了理论支撑。     

应用组织培养技术进行三倍体毛白杨快繁的研究

应用植物组织培养技术对三倍体毛白杨快速繁殖进行了研究 ,结果表明 ,适宜三倍体毛白杨茎段芽增殖的培养基为MS +BA 0 5mg/L +NAA 0 0 1～ 0 0 2mg/L ,适宜叶切块产生不定芽的最佳培养基为MS +BA 0 15～ 0 5mg/L+NAA 0 0 2～ 0 0 5mg/L +IAA 0～ 0 2 5mg/L ,在此培养基上 ,可建立良好的快速繁殖体系。适宜芽生根的培养基为MS +IBA 0 2mg/L ,生根率在 10 0 %。     

百合农杆菌介导的遗传转化受体系统的建立

以麝香百合"素雅"(white-Elegance)作为供试材料建立了百合农杆菌介导的受体系统。鳞茎片的诱导分化以MS培养基中添加0.5mg/L6-BA 0.2mg/LNAA为最好;再生苗鳞茎片的不定芽分化以MS培养基中添加1.0mg/L6-BA 0.2mg/LNAA为最好;再生苗小叶柄的诱导以MS培养基中添加1mg/LNAA为佳。确定了再生苗不同部位适宜的抗生素筛选浓度,卡那霉素的筛选浓度小鳞茎块确定为125mg/L,而小叶柄确定为75mg/L;头孢霉素抑菌浓度确定为250mg/L。     

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.