Effect of Exposure to Heatwave During Blastocyst Formation on Reproductive Performance of Female Rabbits     

F Marco‐Jiménez  C Naturil‐Alfonso  DS Peñaranda  E Jiménez‐Trigos  FJ García‐Diego  JS Vicente 《Reproduction in domestic animals》2014,49(4):629-635

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喜马拉雅紫茉莉正丁醇提取物的化学成分     

邹妍琳  胡益杰  刘爽  令狐浪  兰小中  廖志华  陈敏 《西北农业学报》2014,23(5):202-214

对喜马拉雅紫茉莉(Mirabilis himalaica)正丁醇提取物进行研究,利用反相硅胶柱色谱、Sephedex LH-20、半制备HPLC进行分离,通过理化性质和UV、IR、MS、1 H-NMR和13 C-NMR等方法进行结构鉴定,分离鉴定5个化合物,分别为:腺苷(1),色氨酸(2),1-甲基-1,2,3,4-四氢-β-咔啉-3-羧酸(3),6′-O-(E)-feruloylsucrose(4),丁香树脂酚单-β-D-葡萄糖苷(5),化合物1~4均为首次从该植物中得到,通过还原力和DPPH自由基清除能力试验表明,化合物2、4、5仅有较弱的抗氧化能力。  相似文献   

Expression of Bax and Bim in coxsackievirus B3-infected HeLa cells     

YANG Li  LI Xin  TIAN Lang  HUANG Li-hua  LI Zhuo-ying  YANG Zuo-cheng 《园艺学报》2014,30(3):524-528

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The relative influence of catchment and site variables on fish and macroinvertebrate richness in cerrado biome streams     

Diego R. Macedo  Robert M. Hughes  Raphael Ligeiro  Wander R. Ferreira  Miriam A. Castro  Nara T. Junqueira  Deborah R. Oliveira  Kele R. Firmiano  Philip R. Kaufmann  Paulo S. Pompeu  Marcos Callisto 《Landscape Ecology》2014,29(6):1001-1016

Landscape and site-scale data analyses aid the interpretation of biological data and thereby help us develop more cost-effective natural resource management strategies. Our study focused on environmental influences on stream assemblages and we evaluated how three classes of environmental variables (geophysical landscape, land use and cover, and site habitat), influence fish and macroinvertebrate assemblage richness in the Brazilian Cerrado biome. We analyzed our data through use of multiple linear regression (MLR) models using the three classes of predictor variables alone and in combination. The four MLR models explained dissimilar amounts of benthic macroinvertebrate taxa richness (geophysical landscape R ² ≈ 35 %, land use and cover R ² ≈ 28 %, site habitat R ² ≈ 36 %, and combined R ² ≈ 51 %). For fish assemblages, geophysical landscape, land use and cover, site habitat, and combined models explained R ² ≈ 28 %, R ² ≈ 10 %, R ² ≈ 31 %, and R ² ≈ 47 % of the variability in fish species richness, respectively. We conclude that (1) environmental variables differed in the degree to which they explain assemblage richness, (2) the amounts of variance in assemblage richness explained by geophysical landscape and site habitat were similar, (3) the variables explained more variability in macroinvertebrate taxa richness than in fish species richness, and (4) all three classes of environmental variables studied were useful for explaining assemblage richness in Cerrado headwater streams. These results help us to understand the drivers of assemblage patterns at regional scales in tropical areas.  相似文献   

鲮鱼、麦瑞加拉鲮鱼和露斯塔野鲮的染色体组型比较   总被引：2，自引：0，他引：2  

邬国民  陈焜慈  罗建仁  冼炽彬  明朗 《水产学报》1989,13(3):259-263

近年来,人们对维科染色体的研究报道甚多,认为其染色体的基本二倍数为2N=50和2N=48,变异范围在2N=44～200之间。Gold等认为北美洲已见核型报道的绝大多数鱼类为2N=50。但欧亚大陆大多数为2N=48～50。Arai对欧亚大陆已研究过核型的141种鲤科鱼进行了分析,提出2N=50是鲤科鱼最原始的核型。周暾等对中国鲤科核型的研究也做了大量的工作并得出与Arai一致的结论。  相似文献   

Design and development of a geothermal temperature control system for broodstock management of channel catfish Ictalurus punctatus     

Steven G. Hall  James Finney  R. Paul Lang  Terrence R. Tiersch 《Aquacultural Engineering》2002,26(4):277-289

A control system was designed to raise and maintain water temperatures within 0.03-ha earthen ponds to a range conducive for spawning (24–30 °C) channel catfish Ictalurus punctatus. Heating was done during February 2001 to April 2001, when temperatures would have otherwise prohibited spawning (<24 °C). Temperature was increased from 10 °C (ambient) by 2 °C per day, and maintained at 27 °C, by the addition of geothermally warmed water (36 °C). The control system substantially increased the controllability and precision of heating ponds compared to manual operation. Systems were designed to control sets of four ponds. In designing this control system, consideration of biological constraints was essential. Reproduction in channel catfish is most strongly influenced by temperature. Because cold fronts are common during the winter and early spring (January–March), it was essential to ensure that pond temperatures did not fall below the range for spawning. Constraints on the heating rate and temperature variability to maintain fish health and stimulate spawning behavior were considered. Components of the control system included temperature measurement devices (type-T thermocouples), a central electronic control unit, electronic switches and electrically actuated ball valves. In response to the temperature sensed by each thermocouple, the controller sent a message to close or open the valve. When the valve was opened, warm water was added to the pond to increase the average pond temperature. Hardware and algorithm design and initial system testing were the major components of this project. The final design incorporated information on relevant biological parameters and safety features including peak pond temperature, independent aeration and water pressure control mechanisms. Initial results indicate successful control of this biological system, and ongoing studies suggest similar mechanisms may be used for additional control objectives. In particular, this system could be used to vary pond temperatures to study biological responses and to cool ponds by addition of well water during summer months.  相似文献   

Factors (type,colour, density,and shape) determining the removal of marine plastic debris by seabirds from the South Pacific Ocean: Is there a pattern?     

Valeria Hidalgo-Ruz  Guillermo Luna-Jorquera  Marcus Eriksen  Hanna Frick  Diego Miranda-Urbina  Matias Portflitt-Toro  Marcelo M. Rivadeneira  Christopher J.R. Robertson  R. Paul Scofield  Juan Serratosa  Cristián G. Suazo  Martin Thiel 《水产资源保护:海洋与淡水生态系统》2021,31(2):389-407

1. While floating near the sea surface plastic debris interacts with a number of external factors, including many different organisms. Seabirds have the most extensive documented history of interactions with plastics, through ingestion, entanglement, and nest construction.
2. In the present study, eight seabird species from the South Pacific Ocean were used as a proxy to determine potential patterns of removal of marine plastic debris, and three hypotheses were tested in relation to their feeding habits and nesting areas.
3. Plastics from abiotic compartments (Chilean continental coast, South Pacific Gyre, and Rapa Nui beaches) and biotic compartments (surface-feeding seabirds, diving seabirds, and nesting areas) were compared, according to their type, colour, shape, and density.
4. Continental beaches had a relatively wide range of colours and shapes, with many non-buoyant plastics. Samples from the South Pacific Gyre (SPG) and Rapa Nui (Easter Island) beaches comprised mainly hard, rounded, buoyant, and white/grey plastics.
5. These results indicate that the composition of floating plastics from terrestrial sources changes during transport with oceanic currents, reducing the proportion of prey-like plastics present in the subtropical gyres.
6. The stomach contents of surface-feeding and diving seabirds were dominated by hard, white/grey, and round plastic items, similar to plastics from the SPG, suggesting non-selective (accidental or secondary) ingestion.
7. Nesting areas had a more variable composition of brightly coloured plastics, suggesting a pattern of selective removal of plastics by seabirds, probably from oceanic sources.
8. The present study reveals extensive interactions of seabirds with plastics on a broader scale, which is highly relevant given that the impacts of plastics on seabirds are increasing worldwide, compromising their efficient conservation.

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区域植被对不同时间尺度气象干旱的响应——以贵州省为例     

皮贵宁  贺中华  张浪  杨铭珂  游漫 《水土保持研究》2022,29(4):277-284+291

为探究贵州省植被生长变化趋势对多时间尺度气象干旱的响应,基于2001—2020年的逐月MODIS-NDVI、EVI影像和气象数据,利用皮尔森相关系数、slope趋势性分析等方法,对贵州省20 a的植被生长状况及气象干旱时空变化特征进行了分析。结果表明:(1)贵州省不同时间尺度下的SPEI在整体上呈现出缓慢增加趋势,表明干旱程度有所降低; 空间分布上干旱化趋势表现在北部的遵义、铜仁及黔西南地区。(2)贵州省植被生长状况整体呈现出增加趋势,空间分布上的黔东南地区以降低趋势为主,毕节西部地区以增长趋势为主;(3)贵州省植被生长状况与不同时间尺度的气象干旱呈现出不同程度的正相关性,以贵州省植被在黔西南和北部地区对干旱的响应最强,其次为贵阳和毕节东部; 不同的土地利用类型中,草地对SPEI₃的响应最强,其次为耕地和林地; 生长季内的不同植被类型对SPEI₃和SPEI₁₂的响应较强。综上,贵州省植被和气象干旱时空分布特征存在一定的差异性,且不同植被类型对不同时间尺度气象干旱的响应情况也有所差别。  相似文献   

旺根技术培育的3种植物田间长势调查     

王贵璜  余浪  张宝琴 《热带农业科学》2014,(1):13-18

陈新独创"旺根技术"能促使植物根系发达,移栽田间后保持强盛生长力,提前投产。测定儋州基地旺根技术培育的沉香、花梨木和斯里兰卡橄榄苗木的树高和地径等指标,结果表明,移栽1.5年的沉香和花梨木的平均地径分别达到(5.84±1.43)cm和(4.04±0.64)cm;而移栽2.5年的沉香、花梨木和斯里兰卡橄榄,平均地径分别为(12.10±1.89)cm,(9.37±1.05)cm和(15.26±3.18)cm,均已开花结果,且硕果累累。此外,旺根植物间隔3个月的平均地径增大明显,沉香为1.0 cm,花梨木为0.7 cm,斯里兰卡橄榄为1.44 cm,比传统苗木的生长速度提升数倍。该技术为作物超高产研究提供栽培依据。  相似文献   

海南南药黎药发展研究     

张浪  任军方  云勇 《农业科学与技术》2014,(10):1770-1773

分析了海南南药黎药开发利用现状、发展优势及存在问题,提出海南发展南药黎药产业的思路、对策,旨在为政府有关部门和投资者提供参考。  相似文献