Impact of site conditions and farming practices on the occurrence of rare and endangered weeds on arable land in the Czech Republic     

M Kolářová  L Tyšer  J Soukup 《Weed Research》2013,53(6):489-498

This article documents the impact of site conditions and farming practices on the occurrence of rare and endangered weeds on arable land in the Czech Republic. A survey was conducted between 2006 and 2008 in winter cereals, spring cereals and wide‐row crops. The relationship between the occurrence of plants and explanatory factors was analysed using a multivariate analysis to calculate species frequencies in different types of farming, crops and altitudes. In total, 290 relevés were recorded, with a total number of 172 weed species. Nineteen weeds, classified as rare and endangered species according to the national Czech list, were identified in 106 relevés. The highest effect on the occurrence of rare and endangered weed species was observed for altitude. Almost half of the recorded endangered and rare species belonged to the thermophilous weed vegetation typical for cereals on basic soils. A higher occurrence of endangered species has been confirmed for organic farming, where the sum of frequencies was 4.5 times higher than in conventional farming. Field size was not included in our analyses, but could be a factor affecting weed assemblages. The highest frequency of rare species was recorded in spring cereals, followed by winter cereals and wide‐row crops. Higher numbers were identified within fields with higher weed coverage. Lower farming intensity and diversified farming systems at higher altitudes provided better conditions for the occurrence of rare species than intensively farmed lowlands.  相似文献   

绿茶和红茶提取物抑制中波紫外线诱导HaCaT细胞氧化损伤和凋亡的比较     

马蕊  刘仲华 《湖南农业大学学报(自然科学版)》2013,39(4):377-381

为比较绿茶、红茶提取物对中波紫外线(UVB)诱导角质形成细胞光损伤的抑制作用,用不同浓度的绿茶、红茶提取物对人表皮角质形成细胞(HaCaT)预处理6 h,以60 mJ/cm2的剂量照射细胞,比较细胞生存率和细胞上清液中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH–Px)、乳酸脱氢酶(LDH)的活性以及丙二醛(MDA)含量的变化,用荧光法检测细胞内活性氧(ROS)的含量,用流式细胞仪检测细胞的凋亡变化,并对绿茶、红茶的茶多酚及儿茶素类物质含量进行比较。结果表明：与空白对照组相比,UVB辐射模型组的HaCaT细胞活性下降了21.61%,细胞损伤严重;与UVB辐射模型组相比,绿茶、红茶提取物可提高UVB辐射后HaCaT细胞的存活率,提高SOD、GSH–Px活性(P<0.01),降低LDH活性、MDA含量和细胞内氧自由基含量(P<0.01),降低由UVB辐射导致的细胞凋亡率(P<0.01),使细胞凋亡率分别降低了6.94%和3.68%;绿茶中茶多酚和儿茶素类物质的含量明显高于红茶,绿茶提取物的抑制效果优于红茶提取物。综合分析以上结果,认为绿茶、红茶提取物可以减少由UVB辐射导致的HaCaT细胞损伤和凋亡,具有光保护作用,其机制与细胞抗氧化能力的增强和氧自由基的加速清除有关,且绿茶提取物的作用效果比红茶提取物的好。  相似文献   

Efficacy of Newcastle disease virus recombinant expressing avian influenza virus H6 hemagglutinin against Newcastle disease and low pathogenic avian influenza in chickens and turkeys     

Schröer D  Veits J  Keil G  Römer-Oberdörfer A  Weber S  Mettenleiter TC 《Avian diseases》2011,55(2):201-211

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Fatal epizootic equine herpesvirus 1 infections in new and unnatural hosts     

Wohlsein P  Lehmbecker A  Spitzbarth I  Algermissen D  Baumgärtner W  Böer M  Kummrow M  Haas L  Grummer B 《Veterinary microbiology》2011,149(3-4):456-460

In a zoological collection, four black bears (Ursus americanus) died from neurological disease within six months. Independently in a geographically different zoo, two Thomson's gazelles (Eudorcas thomsoni) and 18 guinea pigs (Cavia porcellus f. dom.) suffered from neurological disorders. In addition, guinea pigs showed abortions and stillbirths. All affected animals displayed a non suppurative meningoencephalitis with intranuclear inclusion bodies. Immunohistology demonstrated equine herpes virus antigen and ultrastructurally herpes viral particles were detected. Virus isolation and molecular analysis identified neurotropic equine herpesvirus (EHV) 1 strains in both epizootics. There is serological evidence of a possible virus transmission from other equids to the affected animals. Cross-species transmission of EHV-1 should be considered in the management of captive wild equids and ungulates, particularly with respect to fatal disease in irreplaceable species.  相似文献   

Changes in growth and nitrogen assimilation in barley seedlings under cadmium stress     

Naïma Boussama  Omar Ouariti  Mohamed Habib Ghorbal 《Journal of plant nutrition》2013,36(4-5):731-752

Barley (Hordeum vulgare L. cv. Martin) plants grown in solution culture, were exposed to increasing cadmium (Cd) concentration (0, 5, 10, 25, 50, and 100 μM) for a duration of 12 days. The sequence of important biochemical steps of nitrate (NO₃) assimilation were studied in roots and shoots as a function of external Cd concentration. Cadmium uptake in roots and shoots increased gradually with Cd concentration in the medium. This Cd accumulation lowered substantially root and shoot biomass. The nitrate reductase (NR, EC 1.6.6.1) and nitrite reductase (NiR, EC 1.6.6.4) activities declined under Cd stress. Concurrently, tissue NO₃ contents and xylem sap NO₃ concentration were also decreased in Cd‐treated plants. These results suggest that Cd could exert an inhibitory effect on the assimilatory NO₃ reducing system (NR and NiR) through a restriction of NO₃ availability in the tissues. We therefore examined, in short‐term experiments (12 h), the impact of Cd on NO₃ uptake and the two reductases in nitrogen (N)‐starved plants that were pretreated or not with Cd. It was found that Cd induced inhibition of both NO₃ uptake and activities of NR and NiR, during NO₃ induction period. The possible mechanisms of Cd action on NO₃ uptake are proposed. Further, in Cd‐grown plants, the glutamine synthetase (GS, EC 6.3.1.2) showed a decreasing activity both in shoots and roots. However, increasing external Cd concentration resulted in a marked enhancement of glutamate dehydrogenase (NADH‐GDH, EC 1.4.1.2) activity, coupled with elevated levels of ammonium (NH₄ in tissues. On the other hand, the total protein content in Cd‐treated plants declined with a progressive and substantial increase of protease activity in the tissues. These findings indicate that under Cd stress the usual pathway of NH₄ assimilation (glutamine synthetase/glutamate synthase) can switch to an alternative one (glutamate dehydrogenase). The changes in all parameters investigated were concentration‐dependent and more marked in roots than shoots. The regulation of N absorption and assimilation by Cd in relation to growth and adaptation to stress conditions are discussed.  相似文献   

Antimicrobial activity of the essential oil of Centaurea aladagensis     

Bülent Köse Y  Işcan G  Demirci B  Başer KH  Celik S 《Fitoterapia》2007,78(3):253-254

Composition of the water-distilled oil of the aerial parts of Centaurea aladagensis, endemic in Turkey, was analysed by GC-MS. Hexadecanoic acid (39.3%), caryophyllene oxide (6.6%) and hexahydrofarnesyl acetone (4.3%) were found as main constituents in the oil. The oil was tested against 7 human pathogenic microorganisms.  相似文献   

什么是动植物检疫徇私舞弊罪     

马春生 《中国动物检疫》2000,17(2):6-7

动植物检疫询私舞弊罪是指动植物检疫机关的检疫人员询私舞弊、伪造检疫结果的行为。动植物检疫河私舞弊罪是1997年3月14日八届全国人民代表大会第五次会议修订《中华人民共和国刑法》后新确立的罪名。动植物检疫构私舞弊罪的犯罪构成条件是：回主体必须是我国动植物检疫机关的检疫人员在我国目前的动植物检疫机关有四个：（1）中华人民共和国出入境检疫检验局及其分支机构。《中华人民共和国进出境动植物检疫活》第三条规定,国务院动植物检疫机关和国务院动植物检疫机关在对外开放的口岸和进出境动植物检疫业务集中的地点设立的口岸动植物…  相似文献   

禽流感病原特性及其危害   总被引：1，自引：1，他引：0  

范根成  马艳霞  胡春伟  王春峰 《中国动物检疫》2000,17(6):40-41

禽流感（AI）又称鸡瘟、真性鸡瘟和欧洲鸡瘟,是由A型正粘病毒一禽流感病毒（AIV）引起的,可感染各种家禽和野生鸟类的一种感染和疾病综合症［1］。禽流感病毒的血清亚型多而复杂,同一血清亚型内有不同的变异株,不同变异株对不同禽类的致病性又有很大差异,有的毒株感染禽类后,无任何症状,而有的则可引起75％以上的发病死亡。自1878年意大利首次报道此病以来,已有100多年历史,由于禽流感病毒能感染多种动物,特别是飞禽、候鸟对远距离大范围传播病毒起重要作用,使得该病已乎遍及世界各地。现将禽流感的病原特性及其危害简述如下…  相似文献   

闵行区实施“放心肉”工程措施     

潘锦平  祝涵申  张曹民  王伟禄  马孟祖 《中国动物检疫》2000,17(6):9-11

闵行区是上海市畜牧业重要生产基地之一,1999年度生猪屠宰量达63万多头。屠宰加工的生猪产品除在本区销售外,还大量运往本市中心城区,以满足广大消费者对“热气肉”的需求。为确保肉类卫生质量,让广大群众吃上“放心肉”,1999年闵行区动物防疫监督机构实施了“放心肉”工程的综合技术措施,围绕屠宰检疫这一重点,强化了产地、运输、市场等环节的检疫和监督检查,推行“放心肉”市场,制定有关技术规模和规章制度,取得明显成效。1生猪定点屠宰场硬件设施整改技术闵行区现有统一规划、设置的生猪定点屠宰场4个。1999年全区加大对定点屠…  相似文献   

    

Georg Priehäußer 《Forstwissenschaftliches Centralblatt》1941,63(4):73-84

Ohne Zusammenfassung  相似文献