瓶鼻海豚和糙齿海豚血清转铁蛋白的初步研究   总被引：1，自引：0，他引：1  

冉春丽 《水产学报》2007,31(4):551-555

血清转铁蛋白(serum transferrin,Tf)是一种非血红素结合铁的β球蛋白[1],其主要功能是负责机体中的Fe3 在吸收、储存和利用部位间的传递[2],供合成红细胞的主要成分—血红蛋白(结合和输送氧气的蛋白)和维持核糖核苷酸还原酶(ribonudeotide reductase)的活性[3]。同时,Tf是脊椎  相似文献   

Construction and evaluation of subtractive libraries in association with heat adaptation differentially expressed genes in the rat liver     

XIAO Jun  ZOU Fei  CAI Shao-xi  JIN Yue 《园艺学报》2004,20(6):1082-1085

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礼貌的顺应性   总被引：1，自引：0，他引：1       下载免费PDF全文

秦勃 《安徽农业大学学报》2008,(2):102-104

从语境关系顺应、语言结构顺应、动态顺应、意识程度四个方面对礼貌现象的考察说明礼貌具有顺应性。礼貌的顺应性是指在交际活动中, 处于不同心理状态的交际者根据语境变化选择适宜的礼貌策略来表达自己的思想。忽视礼貌的顺应性是礼貌原则存在不足之处的根本原因。  相似文献   

A commentary on current approaches to forest population genetics     

Hans-Rolf Gregorius  Philippe Baradat 《New Forests》1992,6(1-4):409-420

Some of the most frequently chosen approaches to forest population genetics as reflected in the present volume are discussed, and some topics possibly deserving more attention are addressed. Among the first are studies of self-fertilization as a characteristic of forest tree mating systems, gene markers as indicators of adaptive or phylogenetic differentiation, and methodological aspects of the measurement of genetic differentiation. The latter mainly concern generalizable methods of analysis and the involvement of gene markers in the determination of mating systems, detection of mechanisms of frequency dependent selection, and the incorporation of genetic profiles (characteristics of frequency distributions of genetic types) into population genetic analysis.  相似文献   

The Equine Neonatal Cardiovascular System in Health and Disease     

《Veterinary Clinics of North America: Equine Practice》2015,31(3):545-565

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焉耆盆地土壤养分系统敏感性空间分异特征研究     

盛洋  刘维忠  刘新平 《农业机械学报》2023,54(5):295-307

在全球变化背景下,揭示土壤养分系统对气候和人类耕地利用活动变化的响应对于农业可持续发展至关重要。基于焉耆盆地的气候、耕地利用强度(LUI)和土壤养分数据,采用敏感性、贡献率和GIS方法分析了土壤养分系统对气候和人类耕地利用活动变化的敏感性及其空间分异特征。结果表明：焉耆盆地气候暖湿化趋势明显(气温倾向率为3℃/(10a),降水量倾向率为39 mm/(10a)),LUI微幅上升;土壤养分系统对气候和LUI变化的敏感性存在显著的空间差异和响应差异。土壤养分系统对气温变化敏感性的空间异质性更高,对LUI变化敏感性更具有响应深度;气候和LUI对土壤养分系统变化的贡献率空间分异明显,并且LUI的贡献率大于气候;土壤养分系统的敏感性及其空间布局是自然环境和人类耕地利用活动相互调节和空间分异的综合结果。研究结果可为提高区域土壤养分系统应对气候变化的能力和耕地精准高效管理提供科学依据。  相似文献   

农户与政府气候变化认知及适应措施比较研究——以河南省为例          下载免费PDF全文

全水萍  李颖明  汪明月 《农业资源与环境学报》2022,39(4):847-854

基于河南省314家麦农和30个基层政府部门55名工作人员的实地调研数据,对农户和政府的气候变化认知与适应措施进行比较研究。结果显示,麦农和基层政府对气候变化及其对农业生产的影响具有较高的认知度。其中,对于气候系统的变化,麦农的认知度高于基层政府;对于气候变化的具体表现和气候变化对农业生产的影响,麦农的认知度低于基层政府。研究还发现,麦农和基层政府对气候变化适应措施的选择偏好不同。超过80%的小麦种植户采取了气候变化适应措施,但主要是增加农药化肥投入和增加灌溉等被动性适应措施,基层政府倾向选择营造农田防护林和推广农作物新品种等主动性适应措施。对于气候变化适应的政策支持,加强气候变化相关的教育和培训、推荐农作物新品种、暴雨和干旱预警是麦农和基层政府的共同选择。  相似文献   

平原河网水中悬浮颗粒物对金鱼藻、水网藻的影响   总被引：3，自引：0，他引：3  

黎明  刘德启  姜海燕  陆露璐  蔡晔  张静 《淡水渔业》2007,37(1):34-38

研究了水体悬浮颗粒物对修复植物的影响规律,结果揭示了悬浮颗粒物对水生植物影响的两面性以及修复植物对颗粒物胁迫产生自由基进行清除的适应机制。在正常情况下,金鱼藻(Ceratophyllum dem ersumL)体超氧化物歧化酶活性维持在256~280 U/g(鲜重),过氧化物酶活性维持在80~90 U/g(鲜重)的水平,保证了细胞膜脂质氧化的分子标志物MDA的代谢水平低于65μmol/g(鲜重)。当金鱼藻受到大于300 mg/L颗粒物的高强度胁迫时,其体内这两种抗氧化酶活性不仅没有维持在很高的水平,反而均呈下降趋势,致使金鱼藻体内的MDA平均值可达79μmol/g(鲜重)以上,形成了对细胞膜相对损伤率达35%以上的氧化损伤结果。在高浊度水体中水网藻(Hydrodictyon reticulatum)内比金鱼藻具有更强的适应性,因此水网藻更合适作为先锋修复植物。  相似文献   

Taurine transporter from the giant Pacific oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis>: function and expression in response to hyper- and hypo-osmotic stress     

Masatomi Hosoi  Chuya Shinzato  Masaya Takagi  Shoko Hosoi-Tanabe  Hideki Sawada  Eri Terasawa  Haruhiko Toyohara 《Fisheries Science》2007,73(2):385-394

ABSTRACT:   Taurine is the primary osmolyte in marine molluscs, whose cellular osmo-conforming process is vital for environmental adaptation because of a lack of osmotic homeostasis. Here, cDNA cloning and expression, and functional analyses of taurine transporter (TAUT) from the giant Pacific oyster are reported on. The deduced amino-acid sequence of oyster TAUT (oyTAUT) showed 47–51% identity to those of vertebrate TAUT, whereas identity among the vertebrates is 78–95%. Functional analysis of oyTAUT expressed in Xenopus oocytes revealed that oyTAUT has a lower affinity and specificity for taurine and a requirement for higher NaCl concentration, compared with vertebrate TAUT. Taken together with similar functional properties of TAUT from mussel, indicated by our previous study, it is possible that these functional features reflect the internal environment of the molluscs (i.e. higher taurine and NaCl concentrations). Oyster taurine transporter mRNA expression was induced by not only hyper-osmotic stress, similar to other TAUT, but also hypo-osmotic stress. It is speculated that the expression in response to hypo-osmotic stress was induced by a substantial decrease in tissue taurine content following the decrease in the internal osmolality.  相似文献   

Overview of Impacts of Climate Change and Adaptation in China's Agriculture     

《农业科学学报》2014,13(1):1-17

The purpose of this paper is to document the likely impacts of climate change on China’s agriculture and the current adaptation efforts made by government and farmers.The review of literature shows that climate change will have a significant impact on agriculture,primarily through its effect on crop yields.The extent of predicted impacts highly depends on the crop,the CO2 fertilization effect assumption and adaptation abilities.Market response to the production shocks resulting from climate change will lessen the impacts on agricultural production predicted by natural scientists.On adaptation,the government’s major efforts have been in the developing new technologies,reforming extension system and enhancing institutional capacity.Farmers do adapt to climate change,but their adaptation measures cannot fully offset the negative impacts of climate change.The paper concludes and makes implications for future studies.  相似文献