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在冬春季节，对内蒙古锡林河中游草原风滚植物进行了调查，共记录12种风滚植物，隶属于藜科、伞形科、菊科等7科。其中，一二年生草本植物和多年生草本各6种；旱生、中旱生植物7种，旱中生、中生植物5种；在区系地理成分中温带亚洲成分（6种）最多。风滚植物是草原枯草期植物的一种存在形式，它的存在为积雪的再分配，局部土壤水分、养分的改善，种子的传播、萌发奠定了基础，具有十分重要的生态学意义。 相似文献
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1 草原区植物区系特征及主要建群种成分评述据有关资料我国草原区植物区系共有 1 2 5科760余属 360 0多种 ,平均每属不到 5种 ,与面积大致相当的亚热带常绿林区的 1 460 0种相比要少得多 ,种类贫乏是寒冷、干旱等极端生存条件长期作用的结果。区系中种数最多的是菊科 (约 40 0多种 ,占总种数 1 1 %强 ) ,其次为禾本科、蔷薇科、豆科 (各占 6%、7% ) ,再次含 1 0 0种以上科为毛茛科、莎草科、百合科、藜科、十字花科等 ,此外具有 5 0种以上的科还有蓼科、唇形科、玄参科、石竹科、伞形科、龙胆科、杨柳科、忍冬科等。其余除少数科含有较多种外 ,绝大多数为寡种属 ,其至是单种属的科。草原区系在植物地理上属古地中海区 ,区系的发生是由于古地质变迁第四纪冰期后、地壳上升、低温及旱化作用明显增强 ,组成草原植被的旱生类群逐渐发展而取代第三纪的由中生植物类群组成的亚热带针、阔叶林和稀树草原植被类型。长期干旱、寒冷作用 ,使草原植物以各类温带成分为主 ,建群种、优势种多数是亚洲中部成分、蒙古成分与欧亚温带成分 ,在东部沙区—草原区中建群植物约2 9属 5 0多种 ,属于欧亚温带草原成分的有糙... 相似文献
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科尔沁草地有毒植物及其防除 总被引：2，自引：0，他引：2
根据大量的调查和资料整理，查明科尔沁草地有毒植物共１６４种，隶属于４２科９３属。生活型和水分生态类型分析表明，该草地的有毒植物成分中多年生中生、中旱生草本植物占多数。在水分条件较好的草地类型或局部地段有毒植物分布较多。本文归纳了有毒植物所含的毒物成分，指明了引起家畜中毒机会较多的植物种类，探讨了草地有毒植物的防除措施，指出毒草防除工作应列为草原建设的一项内容。 相似文献
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保护区的建立对于保护物种多样性,保护生态环境尤为重要.对保护区草地植物区系、物种多样性的空间分布现状及规律的研究有助于保护区的管理.于2009年7-8月,对辉河国家自然保护区草地植物区系及植物多样性空间分布现状进行了研究,以期为辉河国家自然保护区的管理实践提供理论依据.结果表明:研究区有种子植物154种,分属30科,108属;研究地区草地植物区系地理成分较为简单,以世界广布类型占主导地位,草地植物以旱生草本为主;研究区域草地植物种类存在空间异质性,从高纬度到低纬度,草地植物种类呈现先增加后减少的趋势;在经度方向,自西向东植物种类同样呈现先增加后减少的趋势,且这种变化趋势与海拔高度变化有关. 相似文献
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科尔沁沙地植物的生态及分布区型结构分析 总被引：2，自引：0，他引：2
为调查科尔沁沙地草原近年来植物多样性和植物生态特征,以反映该地区环境变化和植物生态适应性。本研究于2013年8月选取科尔沁沙地共56个样地,对样地植物按典型的科、属、种分类系统和株生长型、根生长型、Raunkiaer生活型、水分生态型及分布区型进行调查和分类,结果表明,科尔沁沙地具有典型的地面芽植物气候、中旱生生境条件、植物分布区系结构复杂的特征,共发现121种植物,隶属于31个科,6个株生长型,5个根生长型,6个生活型,5个水分生态类型和13个分布区型。其中,禾本科最多,占23.1%;菊科和豆科分别占22.3%和11.6%。株生长型结构以直立型种类最多,占37%;分枝型和丛生型分别占30%和19%。根生长型结构以直根型的种类最多,占61%;刷状根型和根茎型分别占22%和15%。生活型结构以地面芽植物种类最多,占35%;一年生植物和地面-地下芽植物分别占26%和14%。水分生态型以中生型植物种类最多,占44%;旱生型和中旱生型分别占26%和23%。分布区型结构中,蒙古-东北-兴安-华北分布区型(Mo-N-D-C)的植物种类占据首位,达30%;接下来是蒙古分布区型(Mo)和蒙古-东北-华北(Mo-N-C)分布区型,分别占18%和10%。结果表明,科尔沁沙地草原目前处于生态恢复的早期阶段,植物区系较复杂,水分环境没有发生重大变化,有利于该地区植物正向演替,但表层土壤生态环境依旧脆弱,一年生植物数量占绝对优势,应继续加强草地管理,合理保护和利用植物资源。 相似文献
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《畜牧与饲料科学》2012,33(12)
随着气候干旱变化和重牧利用对草地的影响,我国北方草原退化日益加重,沙化的面积逐步扩大,严重破坏了自然生态环境平衡.研究适应北方干旱环境的旱生、超旱生植物资源,改良退化植被,恢复生态环境,是我国目前亟待研究的重要课题.
驼绒藜属[Ce ratoides(Tourn.) Gagnebin)]植物是干旱、半干旱地区草原植被类型中的重要植物,属旱生、超旱生半灌木,在荒漠和半荒漠化草原地区是马、羊、骆驼等家畜四季喜食的优良饲草.此外,该属植物还具有良好的防风固沙作用,被誉为沙漠中的"绿色卫士",是改良天然放牧草地最有前途的牧草之一.因此,驼绒藜属植物在改良草原及荒漠化防治中的应用研究具有深远意义.
驼绒藜属牧草是藜科一个最古老的属.全世界共有7个种,主要分布于北温带干旱、半干旱地区,世界分布范围较广,在欧亚大陆,西起西班牙、东至西伯利亚、南至伊朗和巴基斯坦都有分布.我国有4个种和1个变种,分别为:华北驼绒藜(Ceratoides arborescens)、驼绒藜(C.latens)、心叶驼绒藜(C.ewersmanniana)、垫状驼绒藜(C.compacta)和长毛垫状驼绒藜(C.compacta var.longipilosa),主要分布于内蒙古、甘肃、宁夏、青海、新疆和西藏等省(区). 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献
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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献