Revegetating Russian Knapweed (Acroptilon Repens) Infestations Using Morphologically Diverse Species and Seedbed Preparation

Highly degraded pastures and rangeland dominated by Russian knapweed (Acroptilon repens [L.] DC) are often devoid of desirable plants. Control efforts may be ephemeral because propagules of desirable species are not available to reoccupy niches made available by control procedures. Establishing desirable, competitive plants is essential for enduring management and restoration of Russian knapweed and other weed-infested plant communities. The objective of this study was to investigate the effectiveness of revegetating Russian knapweed–infested pastures with 3 nonnative, morphologically diverse species following 1 of 3 seedbed preparation treatments. In successive years, at 2 similar sites in southeastern Oregon, we sprayed Russian knapweed with glyphosate, then prepared the seedbed by burning, tilling, or leaving untreated. Following seedbed preparation, we seeded a perennial forb (alfalfa [Medicago sativa L.]), a bunchgrass (Siberian wheatgrass [Agropyron fragile {Roth} P. Candargy subsp. sibericum {Willd.} Melderis]), and a sod-forming grass (pubescent wheatgrass [Elytrigia intermedia {Host} Nevski subsp. trichophora {Link} Tvzel]) in monocultures and 2- and 3-species mixtures. We measured Russian knapweed and seeded-species density 1 and 2 years following seeding. The forb-seeding treatment decreased reinvasion of Russia knapweed by 50%–60% at 1 site, but otherwise, seeding treatment had little influence on total seeded-species density or Russian knapweed density. Tilling generally resulted in a 35%–40% reduction in Russian knapweed density compared with the control and resulted in the highest establishment of seeded species. Variability in annual precipitation appeared to influence seeded-species establishment between the sites. Our results suggest shallow tilling (10–15 cm) followed by drill-seeding desirable forbs and grasses may provide the best results when revegetating Russian knapweed infestations. Follow-up management should include strategies to enhance desirable species production while minimizing Russian knapweed reinvasion.     

Native Plant Growth and Seedling Establishment in Soils Influenced by Bromus Tectorum

The invasion of 40 million hectares of the American West by cheatgrass (Bromus tectorum L.) has caused widespread modifications in the vegetation of semi-arid ecosystems and increased the frequency of fires. In addition to well-understood mechanisms by which cheatgrass gains competitive advantage, it has been implicated in reducing arbuscular mycorrhizal fungi (AMF) abundance and taxa diversity. We evaluated this possibility at a high elevation site in a two-pronged approach. To test whether cheatgrass changed native AMF communities in ways that affected subsequent native plant growth, we grew cheatgrass and native plants in native soils and then planted native plants into these soils in a greenhouse experiment. We found that cheatgrass-influenced soils did not inhibit native plant growth or AMF sporulation or colonization. To test whether soils in cheatgrass-dominated areas inhibited establishment and growth of native plants, cheatgrass was removed and six seeding combinations were applied. We found that 14.02 ±  seedlings · m⁻² established and perennial native plant cover increased fourfold over the three years of this study. Glyphosate reduced cheatgrass cover to less than 5% in the year it was applied but did not facilitate native plant establishment or growth compared with no glyphosate. We conclude that cheatgrass influence on the soil community does not appear to contribute to its invasion success in these high elevation soils. It appears that once cheatgrass is controlled on sites with sufficient native plant abundance, there may be few lingering effects to inhibit the natural reestablishment of native plant communities.     

多种动物血清中生物活性LH/CG的放射受体测定法(RRA)

利用绵羊卵巢黄体细胞膜作为 LH / CG受体来源 ,以放射性12 5 I- h CG作为示踪标记配体 ,以高纯度的h CG为标准品建立标准曲线 ,建立了一种有效的 LH- RRA测定方法。它能够直接检测多种动物血清中与受体结合的具有生物活性的 LH的动态变化。该法测定程序简单 ,在 2 h内完成并获得可重复性结果。测定方法的灵敏度为 0 .3ng/管 ,批内和批间误差分别为 ( 3.4 1± 3.14 ) %和 ( 8.70± 7.93) %。动物 (牛、兔、猪 )垂体液中 LH含量反应曲线和 h CG标准曲线平行良好。牛、羊、猪、兔、鼠和仓鼠血清中 LH的剂量反应曲线和h CG标准曲线的平行性表明 ,该 LH- RRA可以用来检测不同动物血清中的具有生物活性的 LH变化。回收试验表明 ,在该测定方法中加入 3、10、30 ng h CG时的回收率分别为 ( 10 0 .59± 5.55) %、( 99.55± 9.86 ) %、( 10 4 .2 8± 7.4 5) %,说明测定结果的正确性。该 LH - RRA的测定结果反映了动物正常的生理状态。本试验垂体中有活性的 LH水平远远高于外周循环中的水平 ,雌、雄动物循环血液中的 LH含量不一致。     

Climatic Influences on Establishment Pulses of Four Artemisia Species in Nevada

Shrub recruitment in arid and semiarid regions often occurs in pulses controlled by specific weather events. Previous research suggested that Wyoming sagebrush in Wyoming is no exception. We examined four species/subspecies of sagebrush in Nevada, in 2009 and 2010, to discover if evidence of recruitment pulses was contained in the annual growth-ring records. Sagebrush species and subspecies occur on a wide variety of ecological sites that require different management strategies. Species included black sagebrush (Artemisia nova A. Nelson), Wyoming big sagebrush (Artemisia tridentata subsp. wyomingensis Beetle & Young), Lahontan sagebrush (Artemisia arbuscula subsp. longicaulis Winward & McArthur), and low sagebrush (Artemisia arbuscula Nutt. ssp. arbuscula). Eighty stem sections were collected from each of 24 stands (6 stands per species or subspecies) at different geographic locations along east-west or north-south gradients where each species or subspecies naturally occurred. Annual growth-ring analysis was used to determine the year of establishment and the relationship between recruitment and weather events. Results indicated stand ages and locations were different (P > 0.001) among species and subspecies, and years of recruitment were strongly correlated with local and hemispheric weather patterns. Linear and multiple regressions modeled recruitment pulses for all four species. Weather-based predictor variables indicated complex interactions between recruitment and climatic controls. Pacific Decadal Oscillation (PDO) index variables were prominent predictors for all four species at their associated sites. Other important local weather variables included total annual precipitation the year before recruitment, the year of recruitment, and the year following recruitment. In Nevada and the Great Basin, it is imperative that successful sagebrush seeding technologies are discovered and implemented. Ecological restoration and postfire rehabilitation methods should be timed correctly with respect to precipitation patterns (positive phase PDO) and/or designed to mimic conditions responsible for natural sagebrush recruitment.     

呼和浩特市本土草坪草与引进草坪草竞争特性研究进展

本文综述了呼和浩特市本土草坪草与引进草坪草竞争特性研究的科学意义,国内外研究现状及研究展望。特色与创新之处在于:分析各种可控条件对本土草坪草与引进草坪草竞争、生存能力的影响,为探究有效保护本土草坪草、降低外来物种入侵率提供参考。     

灌溉对白三叶生殖生长及种子产量和质量的影响

白三叶(Trifolium repens L.)是温带重要的豆科牧草,在我国草地改良及生态环境建设中具有重要作用。而目前我国白三叶种子主要依靠进口,其生产研究匮乏、技术落后,使之生产利用受到严重制约。本研究以白三叶海法品种为对象,于2003年11月-2005年6月在云南省种羊场,采用随机区组试验设计,设置5个水分调控处理;结合室内土培法,通过对白三叶种子田需水量及灌水时间的确定,水分对白三叶种子产量及产量构成要素的影响、对营养生长与生殖生长的调控、对种子发育及种子质量的影响等方面研究其种子生产的高产灌溉制度,并从生理生化的角度研究水分对白三叶生长发育的调控。     

Preliminary Observations on the Relationships of Barbus Species From Cape Coastal Rivers,South Africa (Cypriniformes: Cyprinidae)

Observations on the phylogenetic relationships of Barbus species from the southern Cape Province are made in the light of new data on the post-cranial axial skeleton and other osteological and anatomical features. Particular attention is paid to the relationships of the ‘red fin’ Barbus species, and new evidence on the problematical relationships of the rare African cyprinid species Oreodaimon quathlambae, is presented.     

Impact of Cultivation Legacies on Rehabilitation Seedings and Native Species Re-Establishment in Great Basin Shrublands

Little is known about how cultivation legacies affect the outcome of rehabilitation seedings in the Great Basin, even though both frequently co-occur on the same lands. Similarly, there is little known about how these legacies affect native species re-establishment into these seedings. We examined these legacy effects by comparing areas historically cultivated and seeded to adjacent areas that were seeded but never cultivated, for density of seeded crested wheatgrass (Agropyron cristatum [L.] Gaertn.) and native perennial grasses, vegetation cover, and ground cover. At half of the sites, historically cultivated areas had lower crested wheatgrass density (P < 0.05), and only one site had a higher density of crested wheatgrass (P < 0.05). Likewise, the native shrub Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle & Young) had lower cover (P < 0.05) in historically cultivated areas at half the sites. Sandberg bluegrass (Poa secunda J. Presl.) density was consistently lower in historically cultivated areas relative to those seeded-only. At sites where black greasewood (Sarcobatus vermiculatus [Hook.] Torr.) and bottlebrush squirreltail (Elymus elymoides [Raf.] Swezey) were encountered, there was either no difference or a higher density and cover within historically cultivated areas (P < 0.05). Likewise, cover of exotic forbs, especially halogeton (Halogeton glomeratus [M. Bieb.] C. A. Mey.), was either not different or higher in historically cultivated areas (P < 0.05). Bare ground was greater in historically cultivated areas at three sites (P < 0.05). These results suggest that cultivation legacies can affect seeding success and re-establishment of native vegetation, and therefore should not be overlooked when selecting research sites or planning land treatments that include seeding and or management to achieve greater native species diversity.     

浙江绿地草坪草种混播组合筛选研究

根据立地条件和生物学特性,选择高羊茅、草地早熟禾和多年生黑麦草在浙江按照不同比例混合成14种不同类型混播草坪进行试验来筛选浙江建植绿地草坪最优组合。结果表明,14种不同混播草坪质量有所差异,成坪后用模糊数学综合评判法评定草坪质量,以高羊茅(3个品种)70% 20%草地早熟禾(3个品种) 10%多年生黑麦草(1个品种)、高羊茅(3个品种)60% 40%草地早熟禾(3个品种)为好,综合评判值分别为0.721和0.7005。     

乡土物种补播对青藏高原高寒草甸群落稳定性的影响

为了探究高寒草甸天然草地补播乡土物种对草地群落稳定性的影响，本试验以垂穗披碱草（Elymus nutans）、异针茅（Stipa aliena）、中华羊茅（Festuca sinensis）、溚草（Koeleria cristata）、星星草（Puccinellia tenuiflora）、扁蓿豆（Melissitus rutenica）、冷地早熟禾（Poa crymophila）为试验材料，设置5种混播组合，于2017年在青海省贵南县天然草地上进行补播。试验采用方差比率法（Variance ratio，VR）、M.Godron贡献定率法（Contribution law）以及生物量稳定性分析方法，结果表明：5种组合补播后使得群落联结性降低、生物量稳定性增大，群落整体稳定性增强，正向着稳定方向发展；5种组合中，组合D （扁蓿豆+星星草+垂穗披碱草+异针茅+溚草）的生物量稳定性最大，是对草地恢复最有效的物种组合。本试验筛选出了对草地生态修复最有效的物种组合，为草地保护及利用提供了科学依据。     

Paratuberculosis (Johne's Disease) in Cattle and Other Susceptible Species

Paratuberculosis (Johne's disease) is a widespread and costly disease. This consensus statement will summarize recommendations regarding diagnosis, control, and treatment of Johne's disease in cattle and other species. Each section of recommendations is followed by a statement that subjectively characterizes the strength of the supporting evidence. The role played by Mycobacterium avium subsp. paratuberculosis (MAP) in the pathogenesis has been a matter of controversy for many years. This statement concludes with an assessment of the evidence in favor of MAP as a potential zoonotic pathogen.     

Species of flea (siphonaptera) infesting pets and hedgehogs in Germany

The species of flea infesting pets and hedgehogs in Germany were investigated through a survey of small animal practitioners throughout the country who were asked to collect specimens at their veterinary practices. A total of 625 veterinarians/veterinary practices responded and provided 2445 intact anti identifiable flea specimens. These fleas originated from 294 dogs (795 fleas), 334 cats (1152 fleas), 76 hedgehogs (481 fleas), five domestic rabbits (10 fleas), one golden hamster (four fleas) and one ferret (three fleas). Dogs were found to be infested with Archaeopsylla erinacei, Chaetopsylla globiceps, Ctenocephalides canis, Ctenocephalides felis, Hystrichopsylla talpae, Nosopsyllus fasciatus, Paraceras melis and Pulex irritans. From cats, Archaeopsylla erinacei, Ceratophyllus gallinae, Ceratophyllus garei, Ctenocephalides felis, Ctenophthalmus assimilis, Hystrichopsylla talpae, Monopsyllus sciurorum, Nosopsyllus fasciatus, Spilopsyllus cuniculi and Typhloceras poppei were collected. In both dogs and cats the most prevalent species were Ctenocephalides felis (78.9% and 91.6%, respectively) and Archaeopsylla erinacei (21.1% and 12.6%, respectively) followed by Ctenocephalides canis in dogs (5.8%) and Hystrichopsylla talpae in cats (1.2%). The fleas isolated from rabbits were Ctenocephalides felis, Hystrichopsylla talpae and Spilopsyllus cuniculi. Nosopsyllus fasciatus and Ctenocephalides felis were recovered from the golden hamster and the ferret, respectively. The hedgehogs were found to be infested with Archaeopsylla erinacei, Ceratophyllus gallinae and Ctenocephalides felis.     

Evaluating the Effectiveness of Low Soil-Disturbance Treatments for Improving Native Plant Establishment in Stable Crested Wheatgrass Stands

Past seedings of crested wheatgrass (Agropyron cristatum [L.] Gaertn. and A. desertorum [Fisch. ex Link] Schult.) have the potential to persist as stable, near-monospecific stands, thereby necessitating active intervention to initiate greater species diversity and structural complexity of vegetation. However, the success of suppression treatments and native species seedings is limited by rapid recovery of crested wheatgrass and the influx of exotic annual weeds associated with herbicidal control and mechanical soil disturbances. We designed a long-term study to evaluate the efficacy of low-disturbance herbicide and seed-reduction treatments applied together or alone and either once or twice before seeding native species. Consecutive herbicide applications reduced crested wheatgrass density for up to 6 ? 7 yr depending on study site, but seed removal did not reduce crested wheatgrass abundance; however, in some cases combining herbicide application with seed removal significantly increased densities of seeded species relative to herbicide alone, especially for the site with a more northern aspect. Although our low-disturbance treatments avoided the pitfalls of secondary exotic weed influx, we conclude that crested wheatgrass suppression must reduce established density to values much lower than 4 ? 7 plants/m², a range that has not been obtained by ours or any previous study, in order to diminish its competitive influence on seed native species. In addition, our results indicated that site differences in environmental stress and land-use legacies exacerbate the well-recognized limitations of native species establishment and persistence in the Great Basin region.     

聚合酶链式反应检测猪细小病毒方法的研究

本研究依据编码猪细小病毒结构蛋白VP2基因序列,合成了一对寡核苷酸引物,通过减少病毒核酸的提取时间、费用及优化聚合酶链式反应(PCR)的条件,成功地从猪细小病毒(PPV)感染的细胞中扩增出预期的158 bp片段,经EcoRⅠ酶切鉴定,证实了该扩增片段的特异性.经敏感性试验测定,PCR的最低检出量为0.008病毒血凝(HA)单位.这些结果表明本试验建立的PCR对PPV的检测人有快速、简便、经济、灵敏度高和特异性强的特点.     

Establishment of embryo transfer in the musk shrew (Suncus murinus)

The present study established techniques to induce pseudopregnancy, in vitro oocyte cultures from pronuclear to 2- to 4-cell stages, and embryo transfer in musk shrews, a reflex ovulator. Offspring were subsequently obtained by transferring in vivo-developed or in vitro-cultured embryos. Female musk shrews received human chronic gonadotropin (hCG), with or without mating stimuli, from vasectomized males to produce pseudopregnant recipients. Embryos at the 2- to 4-cell stage were collected 44–48 h after mating. Another set of embryos was collected 26–27 h after mating and then cultured for 20 h from the pronuclear to 2- to 4-cell stages. Subsequently, embryos were transferred into the oviducts of pseudopregnant recipients 24 or 48 h after the induction of pseudopregnancy. Offsprings were successfully obtained from recipients that received hCG 24 h before embryo transfer, regardless of mating stimuli. These techniques may be valuable for producing transgenic musk shrews.     

青海玉树高寒地区草坪建植与管理(简报)

青海省玉树州一年一度的"三江源"赛马艺术节是藏民俗文化大汇展,承载着厚重的历史文化积淀,具有鲜明的民族民俗文化特色和广泛的群众基础,对于展示康巴地区独具魅力的自然风光、人文景观和民族风情,弘扬民族文化,拓宽经济合作,促进地方经济发展产生了积极的影响^[1]。作为主会场的扎西科草原近年来由于赛事规模扩大,观光旅游人数较众,天然草地退化严重。为筹备2007年第五届青、滇、藏、川毗邻地区文化旅游节暨玉树“三江源”赛马艺术节在扎西科草原的举行,由玉树县草原站负责实施赛马场草地恢复、建植工作任务。     

南岭山脉三节叶蜂科昆虫种类和区系

南岭山脉共有三节叶蜂28种,隶属于膜翅目叶蜂总科,其中南岭山脉特有种3种。区系分析表明,东洋种22种,占78.57%;其余6种为东洋古北兼有种,说明南岭山脉的三节叶蜂以东洋种占优势。南岭山脉三节叶蜂在我国动物地理区划中共有9个区系组合;其中最多的是华中+华南种,其次是华中种,两者之和已达物种总数的60.72%。南岭山脉不同自然保护区、不同海拔、不同植被类型间三节叶蜂的Jaccard相似性系数均小于0.5,属极不相似或中等不相似。     

牛科家养动物催产素(OXT)基因研究进展

催产素(oxytocin, OXT)系全球首个被测序并人工合成的9肽神经内分泌激素,能以神经递质和激素两种形式发挥功能。以激素发挥功能时,需要与催产素受体(oxytocin receptor, OXTR)结合形成复合物方可发挥生理功能。OXT存在于机体多个组织器官,具有广泛的生物学功能,尤其在哺乳动物泌乳过程中发挥重要的调控作用。本文综述了牛科物种OXT基因结构及其编码多肽的分子特征、OXT与OXTR间的定位与相互识别过程、OXT调控泌乳过程的机制及其在动物生产中的应用,并对其下一步研究进行了展望,以期为深入解析OXT基因的结构与功能提供参考。     

基于AHP的黄土高原乡土地被植物评价体系的建立与应用

以充分发掘黄土高原地区乡土地被植物为目标，采用层次分析法(Analytic hierarchy process，AHP)构建了乡土地被植物综合评价体系，运用该体系对兰州野生地被植物进行了评价。结果显示，该体系中指标权重值的排序为生态适应性＞园艺学特性＞园林观赏性＞开发新颖性，生态适应性最为重要，符合黄土高原地区生态环境特点和绿化需求；在兰州市共调查采集到乡土地被植物70种，其中开发利用价值高的有草地早熟禾(Poa pratensis)、芨芨草(Achnatherum splendens)等共13种；地被特性较好、可适度开发的有细叶鸢尾(Iris tenuifolia)等共31种;开发利用价值一般的有甘青铁线莲(Clematis tangutica)等共14种；三裂绣线菊(Spiraea trilobata)等12种植物对生境要求严格，繁殖难度大，不适宜在兰州市作地被应用。该评价体系把定性判断和定量判断相结合，能准确、快速反映乡土地被植物资源特点，可为黄土高原地区开发利用乡土植物提供参考。