改变饲养模式 促进畜牧业可持续发展

近年来,我国畜牧业发展迅速,已经成为建设社会主义新农村的主导产业和增加农民收入的重要渠道。然而,在中国加入WTO以后,畜牧业逐渐国际化、市场化,在这种全球经济一体化的形势下,我国传统养殖方式下生产的畜产品面临着国内外市场的双重压力,"动物福利"是我们无法回避的现实问题。改变现有的生产方式,推行标准化、规范化的饲养模式,是养殖业应对国内外竞争的重要途径,也是实现畜牧业可持续发展的必然趋势。     

浑善达克沙地2种行距黄柳林对风速影响的研究

以浑善达克沙地东南部多伦县大骆驼场境内的黄柳灌木防风固沙沙障为研究对象,分别研究了行距为5 m和8 m的黄柳沙障对障后风速的影响.结果表明:随着高度的增加,沙障的防风效果逐渐降低,而随着风速的增大,沙障的防风效能却明显增强.行距5 m和行距8 m的沙障分别在第3排和第1排障后风速降低最显著.2种行距沙障障内的风速廓线都遵循一元线性回归.     

Analysis of hybrid lethality in F<Subscript>1</Subscript> wheat-rye hybrid embryos

The effect of the Embryo lethality mutant (Eml) of rye was studied in crosses between hexaploid wheat and corresponding inbred rye line (L2). Histological analysis of hybrid embryos revealed morphological differences 16 days after pollination. Eml was found to arrest the formation of shoot meristem but had no influence on root meristem formation. The effect of Eml cannot be overcome by in vitro embryo rescue via direct regeneration on Kruse medium. The possibility of complementary interactions between wheat and rye genes and of changes in gene expression through increased variation in dosage-regulated gene expression during hybrid formation is discussed.     

天胡荽的解剖和屏障结构特征研究

利用光学显微镜和荧光显微镜对天胡荽进行了解剖学和组织化学研究,结果表明,1)天胡荽不定根为初生结构,具二原型维管柱、内皮层、皮层、外皮层和表皮。2)茎、花柄和叶主要为初生结构,除了茎和花柄维管束具次生结构,具表皮、厚角组织、皮层、内皮层、维管束和髓;茎具诱导型通气组织。3)天胡荽不定根的屏障结构包括内侧的有凯氏带且栓质化的内皮层,外侧的有凯氏带且栓质化的外皮层和紧邻外侧具扩散状栓质层的表皮细胞;匍匐茎、花柄和叶柄具相似的质外体屏障结构,一是内侧的有凯氏带且栓质化的内皮层,二是外侧的表皮外角质层,但花柄和叶柄有凯氏带的细胞,并不栓质化;叶片的仅为表皮外角质层。4)天胡荽的解剖和屏障结构特征是其适应多种水湿环境的结构基础。该研究为今后选择湿地生态修复植物提供线索。     

引起种公猪繁殖障碍的营养因素研究

适量的营养水平是提高公猪健康水平和繁殖性能的重要因素,营养水平过低或过高,均可导致公猪健康紊乱和生殖性能减退。作者对引起种公猪繁殖障碍的营养因素进行了综述。     

Cytological Behavior of Hybridization Barriers Between Oryza sativa and Oryza officinalis

Oryza officinalis is one of the important wild species in the tertiary gene pool of Oryza sativa.It has a number of elite genes for rice breeding in resistance or tolerance.However,breeding barriers are so serious that the gene transfer is much difficult by sexual cross method between O.sativa and O.officinalis.Characteristics of the breeding barriers were systemically studied in this paper.When both the diploid (AA,2n=2x=24) and autotetraploid (AAAA,2n=4x=48) cultivated rice were crossed as maternal parents with O.officinalis (CC,2n=2x=24),none F1 hybrid seeds were obtained.The young hybrid ovaries aborted at 13-16 d after pollinations (DAP).By rescuing hybrid embryos,in vitro F1 plantlets were obtained in 2x×2x combinations with the crossabilities lower than 0.5％.Lower rates of double-fertilization and abnormal development of hybrid embryo and endosperm were mainly observed in both combinations of 2x×2x and 4xx2x.Free endosperm nuclei in hybrid degenerated early at 1 DAP in a large scale.Almost no normal endosperm cells formed at 3 DAP.Development of a lot of embryos ceased at globular- or pear-shaped stage as well as some degenerated gradually.The hybrid plantlets were both male and female sterility.Due to the abnormal development,a diversity of abnormal embryo sacs formed in hybrids,and hybrid pollen grains were typically abortive.It showed that conflicts ofgenome A and C in hybrid induced abnormal meioses of meiocytes.     

中国输日茶叶贸易及影响因素研究

本文以中日两国茶叶贸易的相关统计数据为依据,对中国输日茶叶贸易的变化进行了研究,并从日本茶叶生产和消费结构、绿色壁垒、日本茶饮料的发展及中国茶叶国际竞争力等方面对可能的影响因素进行了分析,发现中国输日茶叶贸易有进一步上升的趋势,其中绿茶和乌龙茶的输日潜力较大,同时日本茶叶生产和消费结构对中国输日茶叶贸易影响最大,从根本上决定了输日茶叶贸易必将进一步扩大,而茶饮料市场并未对输日茶叶贸易构成实质影响,日本政府的绿色壁垒及中国茶叶国际竞争力的劣势在中国输日茶叶贸易中起一定的负面影响.     

Habitat suitability analysis for lacustrine brown trout (Salmo trutta) in Lake Walchensee,Germany: implications for the conservation of an endangered flagship species

• 1. The lacustrine brown trout (Salmo trutta) is endangered and of high conservation importance. In the only spawning habitat of the population in the Bavarian Lake Walchensee, the River Obernach, a substantial decrease in spawning runs has been reported. In this study, the present ecological state of the spawning stream was analysed with the objective of identifying life‐stage specific limitations to successful recruitment attributable to deficiencies in (i) spawning migration, (ii) spawning habitat quality, and (iii) habitat quality for juveniles.
• 2. Structural stream analysis showed that discharge and several migration barriers — particularly near the river outlet into the lake — prevent successful spawning migrations at normal water levels. Migration barriers are probably the main limiting factor for reproduction of lacustrine brown trout, whereas structural variability of the Obernach meets the habitat requirements of both spawners and juveniles.
• 3. Spawning site quality was suitable for trout, as indicated by stream substratum texture and high exchange rates between free‐flowing water and the interstitial zone in physico‐chemical parameters (redox potential, dissolved oxygen, pH, temperature and conductivity).
• 4. Analyses of fish community structure revealed dominance of lithophilic species, in particular of riverine brown trout (Salmo trutta). Its density and intact demographic population structure suggest that spawning and juvenile habitat quality for salmonids is not limiting. Recapture of stocked lacustrine trout juveniles also indicates habitat suitability for the juvenile stage.
• 5. In conclusion, the results show that the methodology used in this study is suitable for the identification of life‐stage specific habitat deficiencies in lacustrine brown trout and other fish species. Availability of habitat data throughout the species' distribution range is a first crucial step for the development of an effective recovery plan. Copyright © 2009 John Wiley & Sons, Ltd.

     

技术性贸易壁垒下出口水产品监管思路的探讨

本文概述了近年来中国水产品的出口贸易现状及面临的主要技术性贸易壁垒,并从环境因素、企业自律及监管体系等不同角度对出口水产品召回/通报原因进行了详要分析,并针对具体原因提出了拓展性建议。     

科尔沁沙地活沙障对土壤种子库的影响

选取科尔沁沙地不同生长年限活沙障,调查并测定了土壤种子库的种类组成、密度以及物种多样性等特征。结果表明:(1)仅有封育措施时,流动沙丘没有物种存在。建活沙障后,7年和5年样地的行间和行下物种种类比生长3年样地多,1年生植物逐年增多。(2)随沙障生长年限延长,土壤种子库中种子密度表现出逐年增多的趋势。(3)在物种多样性和相似性方面,建活沙障的样地变化趋势不明显。封育3年后的流动沙丘无物种多样性,与其他样地相比相似性系数为零。(4)建活沙障后,各样地在物种种类和种子数方面逐年增多,认为建黄柳和羊柴网格状活沙障可以达到治理沙丘的目的。