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1.
甘南玛曲高寒草甸草地沙化的研究   总被引:7,自引:1,他引:7  
以甘南玛曲高寒草甸生态系统植物群落样地调查资料为基础,对不同沙化程度植物群落结构及物种多样性特征进行了研究分析。结果表明:随着草地沙化程度的加剧,植物群落多样性指数,均匀度指数及丰富度指数下降,优势度指数增加;禾草地上植物量减少,杂草、莎草地上植物量增加,其中,莎草增加最快。中度沙化阶段是植物群落丰富度、多样性、优势度、地上植物量和均匀度变化的一个转折点,演替早期群落多样性,均匀度及地上总植物量最高,在极度沙化阶段,地上总植物量最低,优势度指数最大。  相似文献   

2.
高原鼠兔洞口区侵蚀过程高山草甸土壤的变化   总被引:4,自引:0,他引:4  
在西藏那曲高山嵩草草甸,选择高原鼠兔活动区域不同高度土堆和不同深度侵蚀坑,分析表层土壤粒度和养分.结果表明,高原鼠兔掘洞形成洞口土堆,造成草甸土壤发生侵蚀,侵蚀程度随着侵蚀坑深度逐渐增加而减弱,在侵蚀坑深度达到20cm时侵蚀基本停止;在侵蚀过程中,细粒物质减少,砾石含量增加.在强烈侵蚀阶段初期,有机物分解条件改善,土堆表层土壤的有机质、全N、全P、水解N、速效K含量提高,但土壤养分物质在侵蚀作用下迅速流失,土壤有机质、全N、全P、水解N、速效P和速效K含量减少;在侵蚀减缓阶段,养分损失速度减缓,补偿作用逐渐增加;在侵蚀基本停止阶段,土壤表层有机质、全N、水解N和速效K含量明显增加.  相似文献   

3.
通过在青海湖的蛋岛、鸬鹚岛、海心山、三块石、布哈河口等鸟类栖息地的鸟类种群数量监测,甘子河乡、沙岛东、克土、小泊湖、湖东种羊场、倒淌河镇元者、青海湖农场、哈尔盖乡、快尔玛乡、生格乡等地进行普氏原羚种群数量监测。目前,普氏原羚种群数量为702—845只。11月份种群数量比8月份增加22只,仅增长4.21个百分点;5个鸟类...  相似文献   

4.
为探讨犬常见肿瘤的发病规律,试验收集哈尔滨地区2016-2017年宠物医院部分犬肿瘤病例71例,采用组织病理学方法对犬肿瘤进行病理学诊断,并对患病动物的品种、性别、年龄、发生部位和饮食情况与肿瘤发生关系进行统计分析。结果显示,71例确诊肿瘤病例中,恶性肿瘤28例,包括鳞状上皮细胞癌3例,基底细胞癌5例,乳腺癌14例,淋巴瘤2例,肾母细胞瘤、精原细胞癌、生殖细胞癌、侵袭性血管黏液瘤各1例;良性肿瘤43例,包括良性乳腺肿瘤15例,纤维瘤10例,平滑肌瘤5例,乳头状瘤和精原细胞瘤各3例,造釉细胞瘤、耵聍腺瘤、脂肪瘤、结节样增生、性索间质细胞瘤、颗粒细胞瘤、肛周腺瘤各1例。上述病例中,乳腺和皮肤是犬肿瘤的高发部位,分别占全部患犬的40.8%和34.0%;患病犬年龄1~16岁不等,平均发病年龄为9.1岁,7岁以后是肿瘤的高发期,中老年犬仍为主要发病群体,但低龄犬发病数量上升;各品种犬均可发生肿瘤,其中杂种犬发病率最高,其次是贵宾犬和京巴犬,且主要为乳腺肿瘤;饮食习惯主要以剩饭剩菜类和肉拌饭类为主,分别占患犬总数的39%和30%;部分肿瘤类型与犬的性别、是否绝育有关,如乳腺肿瘤多发生于未绝育的老年母犬。本研究结果为犬肿瘤的流行病学及诊断提供了参考依据,对犬肿瘤的预防和诊断有一定的借鉴意义。  相似文献   

5.
Specific-pathogen-free chickens inoculated with H5N1 highly pathogenic avian influenza (HPAI) viruses isolated in Japan in 2004 were investigated pathologically. The chickens inoculated intravenously with the viruses died within 26 hr after inoculation. Macroscopically, minimal necrosis of the tip of the comb, and hemorrhages of the palpebral conjunctiva, liver, cerebellum, and muscles were rarely observed. Histologically, dead chickens had minimal focal necrosis of hepatocytes with fibrinous thrombi in sinusoids, mild necrosis of splenic ellipsoids with fibrinous exudation, minimal necrosis of the brain, mild necrosis of epidermal cells of the comb with congestion of the lamina propria, and hemorrhages and edema of the lamina propria of the conjunctiva. Virus antigens were seen in the sinusoidal endothelial cells and hepatocytes in the liver, the capillary endothelial cells of the spleen, the capillary endothelial cells and cardiac myocytes in the heart, the capillary endothelial cells and necrotic nerve cells in the brain, the capillary endothelial cells in the lamina propria of the comb, the renal tubular epithelial cells, and the pancreatic acinar cells. The chickens inoculated by natural infectious routes died within 1-4 days after inoculation. Macroscopically, some chickens had hemorrhages in the conjunctiva, edematous swelling of the face and wattles, hydropericardium, hemorrhages of the proventriculus and bursa of Fabricius, increased secretion of tracheal mucus, and congestion and edema of lungs. Histologic lesions by natural infectious routes were similar to those by intravenous inoculation, except for the pancreatic necrosis. This study suggests H5N1 HPAI viruses isolated in Japan in 2004 cause pathologic conditions similar to natural cases.  相似文献   

6.
王莺  王健顺  张强 《草业学报》2022,31(8):1-12
干旱灾害是制约中国草原生产力的首要自然灾害。通过分析草原干旱风险的形成原因,收集气象、土壤、植被、地形地貌等数据,从干旱灾害的致灾因子危险性、承灾体暴露性和敏感性以及孕灾环境脆弱性入手,建立了草原干旱风险评价指标体系。采用熵权法确定各指标权重,构建了干旱风险评价模型。基于地理信息系统(GIS)空间分析功能,对中国草原进行了干旱风险评估与区划。结果表明,中国草原的较高危险区主要位于内蒙古地区、河西走廊、柴达木和塔里木盆地边缘、青藏高原西部以及云南地区。较高暴露区主要位于中国的西南和华南地区。较高敏感区主要位于内蒙古东南部、东北地区、青藏高原南部和东部边坡、塔里木盆地北边缘以及西南地区。较高脆弱区主要分布在内蒙古中部和东部、甘肃河西走廊、新疆北部、青藏高原大部分地区、云南和川东地区。较高干旱风险区主要位于内蒙古东北部、东北西部、宁夏北部、塔里木盆地北边缘、青藏高原南部、云贵高原、河南和山东地区。研究结果可为中国草原的科学抗旱提供基础数据与理论支撑。  相似文献   

7.
为明确青藏高原海拔对垂穗披碱草(Elymus nytans)青贮饲料发酵品质的影响,本研究以不同海拔区(天祝2 965m、果洛3 763m、当雄4 228m和那曲4 752m)的垂穗披碱草为发酵原料,测定其在青贮14、30、60、90d后的青贮指标。结果表明,随海拔的升高,垂穗披碱草附着乳酸菌数量呈升高趋势,酵母数量呈下降趋势,而霉菌数量受海拔影响小;时间和海拔的互作极显著影响pH、乳酸、乙酸含量和霉菌的数量(P0.001);不同海拔地区的垂穗披碱草同一青贮时间的pH、干物质、乳酸和乙酸的含量以及微生物数量均存在差异(P0.05),且那曲和果洛地区垂穗披碱草青贮饲料的发酵品质优于天祝和当雄地区;当青贮90d时,随海拔的升高,可溶性糖呈降低趋势,粗蛋白呈上升趋势。上述结果表明,在高海拔的那曲和果洛地区,青贮有利于垂穗披碱草保存更多的营养价值。  相似文献   

8.
临床型乳房炎奶牛致病性大肠杆菌血清型研究   总被引:4,自引:1,他引:3  
为有效防治乳房炎以及进一步研究致病性大肠杆菌的危害性,本研究对呼和浩特市某奶牛场16头患临床型乳房炎的奶牛进行采样分析了致病性大肠杆菌。结果表明,在16份粪样、乳样中致病性大肠杆菌的检出率分别为100%和68.75%,血样中未检出致病性大肠杆菌。经动物试验表明,所检出的致病菌均有强致病力。在血清型鉴定中,粪样中分离鉴定出致病性大肠杆菌为O51、O55、O127、O7、O91、O101、O112、O92、O142血清型较多;乳样中分离出的致病性大肠杆菌为O55、O101、O112、O134、O51、O53、O78、O91、O126、O128、O158血清型较多。且粪样中分离出的致病性大肠杆菌42种血清型,乳样中分离出的致病性大肠杆菌33种血清型中具有25种血清型相同,分别为:O8、O35、O44、O51、O55、O61、O62、O65、O69、O80、O91、O92、O95、O96、O98、O99、O100、O101、O112、O120、O127、O134、O142、O153、O158。因此可见,作为环境性病原菌,大肠杆菌侵入乳房而引发了奶牛乳房炎。  相似文献   

9.
《动物营养(英文)》2021,7(4):1145-1151
The unique structure of the stomach, including the rumen, reticulum, omasum, and abomasum, indicates the differences between the ruminant and monogastric animals in the digestion of nutrients. This difference is reflected in the majority of dietary nutrients that may be fermented in the rumen. Significant proteins and a certain amount of starch can flow to the small intestine apart from rumen. The initial phase of small intestinal digestion requires pancreatic digestive enzymes. In theory, the enzymatic digestion and utilization efficiency of starch in the small intestine are considerably higher than that in the rumen, but the starch digestibility in the small intestine is quite low in ruminants. Therefore, improving the digestion of nutrients, especially starch in the small intestine is more urgent for high-yield ruminants. Although the pancreas plays a central role in nutrient digestion, the progress of research investigating pancreatic exocrine regulation in the ruminant is slow due to some factors, such as the complex structure of the pancreas, the selection of experimental model and duration, and internal (hormones or ages) and external (diet) influences. The present review is based on the research findings of pancreatic exocrine regulation of dairy animals and expounded from the physiological structure of the ruminant pancreas, the factors affecting the digestion and exocrine processing of carbohydrates, and the regulatory mechanism governing this process. The review aims to better understand the characteristics of enzymatic digestion, thereby advancing pancreatic exocrine research and improving the digestion and utilization of nutrients in ruminants. Additionally, this review provides the theoretical basis for improving nutrient utilization efficiency, reducing wastage of feed resources, and promoting the efficient development of the dairy industry.  相似文献   

10.
采用Levins生态位指数、Pianka生态位重叠指数和物种多样性指数,分析草甸草原区主要植物种群生态位对封育年限的响应特征。结果表明:退化草地实施封育措施后,群落中主要植物种群生态位宽度发生变化,未封育(对照区)样地以多年生草本植物蒲公英生态位宽度最大;封育年限为4和13年时,生态位宽度最大的物种均为展枝唐松草;封育年限为5、6、8和10年时,生态位宽度最高的物种依次是羊草、麻花头、囊花鸢尾和贝加尔针茅;退化草地实施封育后,物种间生态位重叠指数值集中在0.6~0.9,而未封育样地物种生态位重叠指数值在0.0~0.3;随着封育年限的增加,生态位重叠指数总平均值表现出先增加后降低的变化趋势,其中未封育(对照区)样地主要植物种群生态位重叠指数总平均值最低,封育5年时,主要植物种群生态位重叠指数总平均值最大,为0.68;封育草地的主要植物种群的生态位重叠指数平均值较未封育(对照区)样地增加了40.76%~93.68%;封育年限为5年时,Shannon-Wiener多样性指数、Simpson多样性指数和Margalef丰富度指数、Pielou均匀度指数最大,分别比未封育(对照区)增加了45.46%、16.51%、45.80%和23.38%。封育后,群落多样性、丰富度和均匀度显著增加,并且植物种间竞争加剧,但在封育5年后,随着封育年限的增加,多样性、丰富度以及均匀度逐渐降低,导致生态位分化,种间竞争减缓,群落趋于稳定。因此,从物种多样性角度出发,该区封育时间不宜过长,在封育5年后,可采取适当利用,保护群落多样性。  相似文献   

11.
Components of three cytoskeletal elements, namely, microtubule, intermediate and actin filaments have been localised in the tegument of the 3-week-old juvenile and adult Fasciola gigantica by means of immunofluorescence and immunoperoxidase techniques, using mouse monoclonal anti-alpha-tubulin, anti-cytokeratin antibodies and biotinylated-phalloidin, respectively. The immunostaining with the above probes were also performed in adult Schistosoma mansoni for comparison. The presence of tubulin, indicative of microtubules, was demonstrated in the tegumental cell bodies, their cytoplasmic processes, and the basal layer of the tegumental syncytium of F. gigantica. While in S. mansoni, tubulin appeared as vertical lines stretching across the whole thickness of the syncytium. Cytokeratin, representing one type of intermediate filaments, was detected in the tegumental cell bodies, their cytoplasmic processes, tegumental syncytium and spines of F. gigantica. In contrast, cytokeratin was evident only in the syncytium of S. mansoni, but not in the spines. Phalloidin, which could bind to actin, a subunit of microfilament, was detected in the tegumental cell bodies, their processes, and the microtrabecular network which form the scaffold of the tegumental syncytium of F. gigantica. In S. mansoni, actin was localized in similar tissues except the syncytium was not stained while spines exhibited intense staining. In F. gigantica, the presence of microtubules and actin filaments in the tegumental cells, their processes and in the syncytium could mediate the movement of secretory granules from the cell bodies towards the basal as well as the apical layer of the tegument. Cytokeratin filaments may serve to reinforce the integrity of the tegumental syncytium as well as the spines.  相似文献   

12.
通识教育的研究在我国方兴未艾,概括起来不外乎三个主要方面:本体论研究、本土化研究和实践论研究。其中本体论研究是通识教育的基础理论研究,它是通识教育研究的根本,也是其它两项研究全面展开的基础,通识教育概念的研究更是基础中的基础。除了通识教育外延的模糊性、内涵的多元性、理解的开放性、实施的灵活性以及概念本身的历史变异性等复杂原因给研究带来诸多不便以外,研究方法上的局限也直接影响到研究的进程和结果。文中采用多维论证法,从概念的语素构成、语境生成、语意指向以及外延限量四个维度对通识教育进行了多角度、全方位、分层次、立体化的解析,并得出明确结论,以期引起研究者对此问题的进一步讨论。  相似文献   

13.
Chickens, fattened for 56 days, were treated with nitrovin at the dose of 15 mg per kg of feed, cyadox at the dose of 20 mg per kg of feed, and virginiamycin at the dose of 10 mg per kg of feed. After the fattening, the chickens were studied for the contents of copper, zinc, and manganese in the blood serum, thigh muscle, breast muscle, and feathers. The contents of copper, zinc and manganese in the serum ranged within the limits of physiological values. As for the breast muscle, the content of copper increased but the content of manganese declined in both breast and thigh muscle, as compared with the control group. The feathers contained more manganese in all the groups, as compared with the controls.  相似文献   

14.
松嫩平原贝加尔针茅草甸草原植物组成的结构分析   总被引:15,自引:1,他引:14  
松嫩平原贝加尔针茅草甸草原是蒙古植物区系、东北植物区系、兴安植物区系和华北植物区系4个植物区系相汇集的区域,在全区所设的27个调查样地中,共有153种植物,隶属于34个科,6个株生长型,5个根生长型,6个生活型,4个水分生态类型,15个分布区型和6个饲用价值类型。其中,菊科种类最多占20.9%,豆科和禾本科分别占11.8%;株生长型结构以分枝型种类最多占32%,丛生型和直立型分别为24%和18%;根生长型结构以刷状根的种类最多占55%,直根型和根茎型分别为18%和16%;生活型结构以地面芽植物最多占40%,地下芽植物次之占29%,地面-地下芽植物占15%;水分生态类型结构以中生型种类最多占51%,中旱生型次之占34%;分布区型结构以蒙古-东北-兴安-华北分布区型的种类最多占29%,蒙古-兴安分布区型次之占13%;经济价值类型结构以中、低等质量的种类最多,所占比重高达52%,而优、良牧草种类只占22%。松嫩平原贝加尔针茅草甸草原具有温带草本群落植株和根系的特点,典型的温带地面芽植物气候特征,中生生境条件,复杂的分布区型结构和多样的饲用价值类型。  相似文献   

15.
朱方容  何彬  林强  胡乐山 《蚕业科学》1999,25(3):135-140
对72 个桑树杂交组合进行两种冬伐处理,研究冬伐形式对桑树的花叶病抗性、春叶产量和叶质的影响。结果表明:不同冬伐处理对桑树的花叶病抗性、春叶产量和叶质均有极显著的影响。采用冬留长枝的冬伐形式,可使花叶病的株发病率降低5517 % ,病情指数降低7399 % ,病害对产量的综合损失率降低8645 % ;桑树的总枝条长度、单位条长叶片数、单叶重分别增加3296% 、1233 % 和2377 % ,从而使春叶产量大幅提高,平均增产13593 % ;春叶的干物含量、可溶性糖含量、总糖含量显著提高,桑叶养蚕可使全茧量、茧层量、产卵数、良卵数分别提高388 % 、416 % 、60 % 和60% 。  相似文献   

16.
After cryopreservation for 13.3-15.8 years, the viability of the infective larvae (L3) of Trichostrongylus axei, T. colubriformis, Oesophagostomum columbianum, Haemonchus contortus, Ostertagia circumcincta, T. falculatus, Nematodirus spathiger, Chabertia ovina and Dictyocaulus filaria was assessed in sheep, by being deposited at their predilection sites. D. filaria was, however, an exception, in that the L3 were injected into the jugular vein. The mean development of all the species was 22.8%, but if three species (O. columbianum, C. ovina and D. filaria), that developed poorly are disregarded, then the mean development was 33.4%, similar to previous tests after shorter periods of cryopreservation. The L3 of some of the species appeared sluggish when examined 10-15 min after being thawed, and in the case of H. contortus practically all the larvae of the original batch tested in the previous trials of the series appeared dead when thawed for use in the present trial, and were replaced by another batch of L3 of the same species. When re-examined after about 8 h, however, a high percentage of the L3 of the original batch appeared to have become revitalised, and their viability was tested in a trial reported elsewhere. The intestinal cells of the majority of the L3 of N. spathiger, O. circumcincta and C. ovina were vesiculated when they were thawed. Nevertheless, the degree of development of the former two species was of the highest in the trial, and it can be concluded that this phenomenon does not necessarily impede the viability of larvae.  相似文献   

17.
本文依据西藏那曲地区和日喀则市885份入户调查数据,运用有序Logit模型考察了牧民肉羊养殖规模的影响因素。研究表明:牧民扩大养殖规模较为普遍;牧民的生态环境认知、政策认知、家庭收入水平、肉羊养殖收入比重、文化程度、村民相处情况、村干部经历等对家庭控制肉羊规模有显著正向影响。对此,政府在草原保护中需要强化草原监管中牧民参与、加强政策内容与草原退化情况宣传、提高牧民政策满意度、拓展牧民增收渠道,在降低牧民肉羊养殖规模的同时提高牧民家庭生计水平,进而促进草原畜牧业可持续发展。  相似文献   

18.
为明确白草(Pennisetum centrasiaticum Tzvel.)生殖生长期生物量分配规律,本研究选择西藏自治区日喀则市萨迦县一处白草单优种群落,采用野外调查取样和室内分析方法,研究白草不同生育期的基本生长特征、构件生物量分配特征和构件占比相关关系。结果表明:白草株高、茎粗、凋落物占比、茎占比、叶鞘占比、穗占比、生殖枝占比和地上营养体占比随生育进程呈“∩”型变化;根茎占比从孕穗期65.42%显著下降到灌浆期45.10%,后在成熟期显著上升至63.22%,呈“∪”型变化。白草灌浆期茎叶比2.16,根茎占比45.10%,地上生物量占比达到最大的54.90%,大量干物质未转移至地下部贮存,利用价值最大。因此,白草以地下根茎克隆繁殖作为主要繁殖方式,在生殖生长前期将干物质大量分配到地上部完成有性生殖,在成熟期将干物质转移到地下部贮存。  相似文献   

19.
摘 要:为了综合评价广西主栽的不同红肉火龙果品种的果实品质特性和氨基酸组成,以金都1号、大红、蜜宝、美龙3号四个品种为研究对象,对其果实品质和氨基酸组分及含量等指标进行全面系统的比较,旨在为火龙果的种植生产、加工和食用等提供理论依据。结果表明:4个火龙果品种果实外形端正,色泽鲜艳,品质佳,其中金都1号果实最大,美龙3号最小;金都1号和蜜宝的果形为近圆形,大红和美龙3号为椭圆形;萼片都是三角形,金都1号和大红较长,蜜宝较短;萼片数最多的是大红,最少的是蜜宝;果皮最厚的是美龙3号,最薄的是蜜宝;可食率最高的是蜜宝;金都1号果实的可溶性固形物、可溶性糖、还原糖、可滴定酸、维生素C、甜味氨基酸、苏氨酸、蛋氨酸和脯氨酸的含量以及必需氨基酸在总氨基酸中的比例最高,大红的17种氨基酸总量、必需氨基酸、半必需氨基酸、鲜味氨基酸、芳香族氨基酸、赖氨酸、苯丙氨酸、缬氨酸、亮氨酸、异亮氨酸、组氨酸、精氨酸、门冬氨酸和甘氨酸的含量最高,蜜宝的胱氨酸、丙氨酸、丝氨酸和谷氨酸的含量最高,美龙3号的酪氨酸含量最高。4个红肉火龙果品种果实所含的17种氨基酸中,排在前五位的是谷氨酸、脯氨酸、精氨酸、亮氨酸、门冬氨酸。综合进行评价,金都1号的综合品质性状最佳,其次是大红。  相似文献   

20.
Conidiobolomycosis is reported in the state of Piauí, in the semiarid region of northeastern Brazil. Affected sheep had depression, weight loss, serous or mucohemorrhagic nasal discharge, and cranium-facial asymmetry from exophthalmos of 1 eye, generally with increased volume of the eyeball, keratitis, and corneal ulceration. At necropsy of 60 sheep, friable masses were observed in the posterior region of the nasal cavity, often destroying the ethmoturbinate bones. Frequently, the lesions invaded the nasal sinuses, cribiform plate, orbit, and brain. The masses were irregular, granular with moist surfaces, and soft and friable with white, yellow, or tan coloration. Dissemination of the lesion to lungs was observed in 27 sheep, to the brain in 26, to lymph nodes in 3, to the kidney in 2, and to the gallbladder and heart in 1. The microscopic examination showed granulomatous inflammation composed of central necrosis surrounded by lymphocytes, epithelioid and giant cells, and fibrous tissue. In all lesions, negatively stained structures representing hyphae were surrounded by Splendore-Hoeppli material. Coagulative necrosis, thrombosis, and vasculitis were also observed. Grocott methenamine silver stain showed 8-30-microm-thick hyphae, rarely septate or ramified, irregular in shape, and with black contoured wall, sometimes with bulbous dilatation in the extremities. On electron microscopy, the hyphae had a thick double wall surrounded by cellular remnants and an inflammatory exudate. Conidiobolus coronatus was isolated from the lesions of 6 sheep. Conidiobolomycosis is an important disease of sheep in the state of Piauí, and other regions of northeastern Brazil.  相似文献   

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