共查询到20条相似文献,搜索用时 78 毫秒
1.
1986年1月至1993年12月,作者在浙江萧山围垦农区采用体重法将臭 种群分为5个年龄组。雄体:Ⅰ.幼年组(体重≤308)、Ⅱ.亚成年组(体重>309,≤40g)、Ⅲ.成年1组(体重>40g,≤52g)、Ⅳ.成年II组(体重>528,≤648)、Ⅴ.老年组(体重>64g);雌体:幼年组(体重≤24g),Ⅱ.亚成年组(体重>24g;≤36g).Ⅲ.成年Ⅰ组(体重>369,≤46g),Ⅳ.成年Ⅱ组(体重>468,≤54g),Ⅴ.老年组(体重>54g)。各年龄组的繁殖特性存在差异。种群以成年Ⅰ组为主,但其种群的年龄结构存在有性别差异,雄性种群以成年Ⅰ组、成年Ⅱ组和老年组为主,雌性种群以亚成年组和成年Ⅰ组为主。种群的年龄结构存在季节性变化。在室内,雄性在春季和冬季以成年Ⅱ组为主,夏季和秋季以老年组为主;在室外春季、秋季和冬季均以成年Ⅰ组为主,夏季则以成年Ⅱ组为主。室内雌性在各季节均以成年Ⅰ组为主,而在室外春季和冬季以亚成年组为主,夏季和秋季以成年Ⅰ组为主。其种群年龄结构存在有年变化。 相似文献
2.
布氏田鼠在低温条件下的实验观察 总被引:3,自引:2,他引:1
实验在-20℃的低温下进行,结果表明:(1)单笼饲养鼠平均存活期为145.9±30.8h,其中幼鼠耐低温力最差,然后依次为老体组,亚成体组,成体组,除幼体外,雌鼠的抗寒能力稍高于雄体。(2)饲喂冷蒿组比饲喂其它6种牧草在低温下布氏田鼠的存活期显著延长。(3)聚集中可明显增强对低温的耐受程度。(4)窝草可使巢内温度保持在5~8℃窝巢内层的温度可在这15~22℃ 相似文献
3.
洞庭平原黄胸鼠种群年龄组的划分 总被引:8,自引:1,他引:7
根据胴体重的频次分布和每5g胴体重组的鼠所对应的发育与繁殖状况,将黄胸鼠分为5个年龄组,Ⅰ,幼年组:胴体重≤35g;Ⅱ。亚成年组,36-65g;Ⅲ。成年一组:66-100g;Ⅳ.成年二组:101-135g;Ⅴ.老年组;〉135g。经t检验,各组间的胴体重,体重,体长尾长都有显著性的差异。各年龄组间的体重与胴体重存在显著的正相关前3个年龄组的体长和尾长与胴体重之间有极显著相关性。各年龄组的雌性比变化 相似文献
4.
洞庭平原褐家鼠年龄分组及种群年龄动态分析 总被引:10,自引:1,他引:9
本文采用1986年10月—1989年12月在洞庭平原收集的褐家鼠(Rattus norvegicus)标本,以胴体重作指标,参考繁殖特征,将褐家鼠划分5个年龄组:Ⅰ.幼体组,雌鼠<60克,雄鼠<70克;Ⅱ.亚成体组,雌鼠60—99克,雄鼠70—119克;Ⅲ.成体Ⅰ组,雌鼠100—139克,雄鼠120—169克;Ⅳ.成体Ⅱ组,雌鼠140—189克,雄鼠170—219克;Ⅴ.老体组,雌鼠>190克,雄鼠>220克。种群年龄结构的季节动态特征是:开春时以Ⅲ、Ⅳ组占优势,初夏时Ⅰ、Ⅱ组明显增加,7、8、9月各年龄组比例较均匀,冬季以Ⅱ、Ⅲ组为主。还探讨了年龄与体重、体长、尾长及繁殖率的相互关系。 相似文献
5.
布氏四鼠在低温条件下的实验观察 总被引:1,自引:1,他引:0
实验在-20℃的低温下进行。结果表明。(1)单笼饲养鼠平均存活期为145.9±30.8h。其中幼鼠耐低温力最差。然后依次为老体组、亚成体组、成体组。除幼体外,雌鼠的抗寒能力稍高于雄体。(2)饲喂冷蒿组比饲喂其它6种牧草在低温下布氏田鼠的存活期显著延长.(3)聚集可明显增强对低温的耐受程度。(4)窝草可使巢内温度保持在5~8℃,窝巢内层的温度可达15~22℃。 相似文献
6.
甘肃灵台文王沟晚中新世-早更新世小哺乳动物 总被引:10,自引:8,他引:2
大量小哺乳动物化石在地层中的分布,将文王沟剖面23层划分出5个生物地层带;Ⅰ带相当于榆社马会组;Ⅱ带与Ⅲ带相同庄组;Ⅳ带相当于麻则沟组;Ⅴ带为午城贡土底部。根据生物属种转换判定出4个主要生物事件发生时期,分别在5.8、3.6、.30、2.4Ma左右。每一个生物事件集中发生的时期指示生态环境的一次显著向干冷方向变化。 相似文献
7.
本文在重瓣丝石竹开发与应用研究中对以下三方面问题进行了探讨与研究。Ⅰ.茎尖和茎段组织培养技术及存在问题的分析与研究;最适诱芽培养基为MS+6-BA 1mg/‘L+琼脂8 ̄10g蔗糖30g,克服试管苗玻璃化现象的方法。Ⅱ.不同介质对重瓣丝石竹试管苗生根试验;最佳生根培养基为1/2MS+NAA0.5mg/L+IBA0.5mg/L+珍珠岩+蔗糖30g,介质为珍珠岩。Ⅲ.移载技术研究;最佳入地栽培的土壤配 相似文献
8.
闽江口海蜇渔业生态学研究 总被引:6,自引:3,他引:3
根据1993年5~9月的调查材料,研究了福建闽江口海域海蜇的渔业生态学.其密度和生物量高峰分别出现在6月20日和7月10日;群体伞径范围为18~546mm,平均328.8mm.体重范围为0.5~9540g,平均2877.4g;伞径为345~485mm的雌性有性繁殖力在1120.6×104~3754.8×104粒,平均2444.7×104粒,有性生殖期在8月初至11月;采用高次方程和指数高次方程分别模拟伞径和体重生长,生长方程为:Φt=12.1337+17.7048t+3.1385t2-0.2049t3+0.00302t4,logeWt=-0.5749+1.4818t-0.0771t2+0.00129t3;以生物经济学原理确定7月20日为合理开捕期,开捕伞径为465.8mm.讨论分析了执行合理开捕期和开捕规格,对保护和合理利用海蜇资源,提高经济效益的重要意义 相似文献
9.
窄颖仲彬草Kengyilia stenachyra(Keng) J.L. Yang ,Yen et Baum 是分布于我国西部的一种多年生六倍体植物。将其与犬草Elymus caninus(L.) L., 鹅观草Roegneria kamoji Ohwi, 糙毛仲彬草K.hirsuta (Keng) J.L.Yang,Yen et Baum 3 个种进行了杂交。对亲本及杂种F1 代花粉母细胞减数分裂中期I染色体配对行为进行了观察。减数分裂平均构型分别为: E. caninus×K. stenachyra23-79 Ⅰ+ 5-20 Ⅱ+ 0-27Ⅲ; R.kamoji ×K.stenachyra18-23 Ⅰ+ 11-68 Ⅱ+ 0-06 Ⅲ+ 0-06 Ⅳ; K.hirsuta ×K.stenachyra4-83Ⅰ+ 17-31 Ⅱ+ 0-55 Ⅲ+ 0-20 Ⅳ+ 0-02 Ⅴ。根据以上结果, 结合种的形态特征, 窄颖仲彬草应从鹅观草属Roegneria C. Koch 拟冰草组ParagropyronKeng 中组合到仲彬草属Kengyilia Yen et Yang。 相似文献
10.
中国五种锄足蟾科无尾两栖动物的细胞遗传学研究 总被引:5,自引:1,他引:4
本文对中国5种锄足蟾科无尾两栖动物的骨髓细胞有丝分裂中期作了细胞遗传学研究,内容包括核型、Ag-NORs和C-带。研究结果表明景东角蟾:2n=26(20M+4SM+2ST),5+8,SC和Ag-NORs位于6p^per,同时呈C-带正染。C-带以着丝点区域正染为主;粗皮角蟾:2n=26(20M+6SM),5+8,Ag-NORs在6q^inter,以着丝点C-带为主,但Nos.12,13有明显的端位 相似文献
11.
12.
13.
14.
Michael Hesse 《Plant Systematics and Evolution》1980,134(3-4):229-267
Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout. 相似文献
15.
Surveillance of Class Ⅰ Newcastle Disease Virus at Live Bird Markets and Commercial Poultry Farms in Eastern China Reveals the Epidemic Characteristics 下载免费PDF全文
Xiaolong Lu Xiaoquan Wang Tiansong Zhan Yifan Sun Xin Wang Naiqing Xu Tianxing Liao Yu Chen Min Gu Shunlin Hu Xiaowen Liu Xiufan Liu 《中国病毒学》2021,36(4):818-822
16.
正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various 相似文献
17.
Altaf Hussain Tiantian Wu Hui Li Linjin Fan Kai Li Li Gao Yongqiang Wang Yulong Gao Changjun Liu Hongyu Cui Qing Pan Yanping Zhang Asim Aslam Khan Muti-Ur-Rehman Muhammad Munir Salman Latif Butt Xiaomei Wang Xiaole Qi 《中国病毒学》2019,34(1):102-105
<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV 相似文献
18.
Jiaming Li Yidun Zhang Lina Jiang Hongliang Cheng Jingjing Li Li Li Zehui Chen Fei Tang Yingying Fu Yifei Jin Bing Lu Jing Zheng Zhongyi Wang 《中国病毒学》2022,37(5):762-764
Highlights
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference. 相似文献
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference. 相似文献
19.
Danrong Shi Keda Chen Xiangyun Lu Linfang Cheng Tianhao Weng Fumin Liu Nanping Wu Lanjuan Li Hangping Yao 《中国病毒学》2022,37(2):295-298
Highlights
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID50 method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC50=0.12 IU/mL in Vero cells and EC50=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC50=0.25 IU/mL in Vero cells and EC50=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy. 相似文献
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID50 method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC50=0.12 IU/mL in Vero cells and EC50=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC50=0.25 IU/mL in Vero cells and EC50=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy. 相似文献
20.
Wenming Jiang Xin Yin Shuo Liu Shaobo Liang Cheng Peng Guangyu Hou Jinping Li Xiaohui Yu Yang Li Jingjing Wang Hualei Liu 《中国病毒学》2022,37(4):631-633
Highlights
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection. 相似文献
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection. 相似文献