种业振兴与粮食安全

种业振兴对保障国家粮食安全具有重要的战略意义。推进中国种业振兴以确保粮食安全,必须坚持大国土观与大食物观,在动态发展格局下解决种业的“卡脖子”问题,在协同发展思路下重视种业振兴的必要匹配条件,在国际竞争与合作视野下拓展种业振兴的发展空间。本文从粮食安全决定因素及其优先序的角度揭示了种业振兴的基础性、关键性与决定性作用;在此基础上,回顾中国种业发展的历程,厘清了种业振兴与粮食安全的关系;在新的粮食安全格局下,解析大食物观下种业振兴的内涵与面临的挑战,对未来中国种业振兴的健康良序发展进行展望并提出对策建议。     

脂肪细胞膜免疫对动物体脂含量的调控

降低动物体内脂肪含量,改善畜产品质量一直是动物研究人员研究的重点。近年发展起来的脂肪细胞膜免疫为降低动物体脂含量提供了一种安全而有效的方法。本文简要介绍了脂肪细胞膜免疫的两种免疫方法,并对其发展前景进行了展望。     

国内文献传递发展不平衡性与改进途径研究

针对国内主要文献传递系统CALLS,CSDL,NSTL近几年的运行状况,结合已有的文献传递工作经验,分析文献传递发展过程中存在的制度管理、基础设施、服务方式等不平衡性因素.探讨各因素之间的因果关系与改进途径,为我国文献传递,资源共享的健康发展提供理论与技术支撑.     

藻类在猪和鸡养殖生产中的应用研究进展

文章总结了畜禽生产中可利用的藻类及其营养成分,重点介绍了含藻饲料对以猪和鸡为代表的畜禽生长、免疫、肌肉品质、产蛋性能和禽蛋品质等方面的影响,还指出了藻类在畜禽饲料应用中存在的问题并提出建议,旨在为藻类资源在猪、鸡养殖生产中的广泛应用提供参考。藻类分布广、易生长、产量大,尤其是海藻,含有陆生植物不具有的生物活性物质和营养物质。将富含不饱和脂肪酸和色素的微藻添加到饲料中能改善畜禽肉品质,提升禽蛋品质;将富含多糖等活性物质的大型海藻添加到饲料中有助于提升畜禽免疫力。饲料中添加少量藻类可提高饲料稳定性,提升畜禽生长性能和饲料利用率;当藻类添加量过高时,其所含的抗营养因子会对畜禽产生负面影响,但通过适当的预处理可消除部分抗营养因子,减轻负面效应。     

DEVELOPMENT AND APPLICATION OF CVA,DRIS, AND CND NORMS FOR THREE HYBRIDS OF POPULUS MAXIMOWICZII PLANTED IN SOUTHERN QUEBEC

Plantations of hybrid poplars adapted to relatively poor soils and cold conditions are being established in abandoned fields and forest sites in southern Quebec. Hybrids of Populus maximowiczii are well adapted to these sites but little is known about their nutritional requirements. The objectives of this study were to develop nutritional norms (CVA, DRIS, CND) for three of these hybrids: 915508, Populus euramericana or canadensis X Populus maximowiczii; 3729, Populus nigra X Populus maximowiczii; and 915303, Populus maximowiczii X Populus balsamifera, and to apply the norms on some sites recently planted in southern Quebec. Six plantations (two per clone) were used for the determination of nutritional norms. In each plantation, individual trees were fertilized with nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) according to a factorial design with three levels of application for each nutrient (3⁵ = 243 treatments). Tree diameter and height, unit foliar mass and foliar chemistry (N, P, K, Ca, and Mg) of each tree were determined two years after fertilization. CVA, DRIS and CND norms were determined using a boundary-line approach with each plantation. Nutritional norms could be established for most combinations of clones and nutrients. CVA, DRIS and CND indices produced with published optimum nutrient concentrations for hybrid poplars closely related to P. maximowiczii were generally in agreement with the ones developed in our study. Differences in nutritional norms among P. maximowiczii hybrids/clones were small but hybrid/clone specific norms could provide more precise estimates of tree nutrition. The application of the norms on some representative sites of southern Quebec revealed more frequent nutrient imbalances than true nutrient deficiencies with generally excessive Ca and Mg, and limiting N, P, and K.     

猪瘟乳前免疫及其抗体检测

本试验对新生仔猪哺乳前初次进行猪瘟疫苗免疫,至７０日龄时进行第二次免疫,免疫持续至７０日龄和１５０日龄时两次应用Ｄｏｔ－ＥＬＩＳＡ方法进行检测,结果表明,阳性率分别为９２．３％和９１．２５％,说明此免疫方法是一较好的预防猪瘟的免疫程序。     

滴鼻免疫疫苗对SPF鸡气管功能影响的研究

为研究疫苗滴鼻免疫对鸡气管功能的影响,本研究对SPF鸡滴鼻免疫新城疫疫苗后气管纤毛摆动速率、气管形态结构和黏液分泌进行了研究。80只7日龄SPF鸡随机分为对照组和试验组,每组40只,试验组SPF鸡滴鼻免疫新城疫弱毒疫苗,对照组滴鼻生理盐水;于免疫后的第0、2、4和6天,每组每次随机剖杀10只鸡,应用红细胞示踪法测定气管纤毛摆动速率,采集气管制备石蜡组织切片进行HE和奥新蓝pH 2.5和pH 1.0染色。结果发现,疫苗免疫后的第0和2天试验组SPF鸡纤毛摆动速率较对照组升高,但差异不显著（P>0.05）;滴鼻免疫后SPF鸡气管结构完整,无明显损伤;滴鼻免疫后试验组SPF鸡气管酸性黏液分布容积在免疫后的第0和2天显著高于对照组（P<0.05）,而后明显降低,于免疫后的第6天又有所升高,但差异不显著（P>0.05）;硫酸化黏液分布容积在免疫后的第0和2天显著升高（P<0.05）,而后降低并与对照组相一致。结果表明,新城疫疫苗滴鼻免疫后前两天SPF鸡气管黏液分泌增多,而后恢复到正常水平,疫苗的免疫对气管形态结构和纤毛的摆动速率无明显影响。     

Cities vs countryside: An example of a science-based peri-urban landscape features rehabilitation in Milan (Italy)

Urban-rural boundaries are often abrupt and unmitigated, a trait that significantly enhances their ecological vulnerability. Nonetheless, such fringe systems enclose a high potential in furnishing buffering and resilience functions and services towards the city. Our study intends to give a contribution on the understanding of the ecological behaviour of peri-urban landscape features (PLFs) systems, showing how floristic-vegetational and landscape ecology studies can inform their multi-functional phytocoenoses ecological reconfiguring. Analyses were led among a fringe context of Milan city. An agri-environmental extra-local scale analysis framed the forthcoming finer scale results. Landscape mosaic structural and functional main traits were interpreted, outlining a current impairment of the landscape system capacity to support ecological functions across the area. In parallel, floristic traits were studied through chorological, life forms and Ellenberg’s ecogram analysis (total flora and single sub-areas values). The main phytocoenoses types were qualitatively described and related to the dynamic patterns of reference vegetation series. Results highlighted a significant deterioration of floristic-vegetational traits, if compared to the local potential. Recurrent anthropic disturbances, open space conditions were identified as the major impact factor on phytoconoeses evolution towards higher diversity, complexity and stability traits. Spontaneous recolonization processes were acknowledged as currently unable to change these trends, while past reforestation interventions showed positive effects. These results informed the building of a functional-dynamic interpretative approach, focused on the ecological roles and physical habitat conditions currently influencing phytocoenoses dynamics, and on which to intervene. Accordingly, the current and potential ecological functions of 9 key PLFs categories were inspected. Consequently, design criterions for corrective interventions were outlined. This brought to the identification of the optimal structural and functional patterns of PLFs to be integrated throughout the urban-rural boundary, as well as their floristic-vegetational design specificities, by pursuing a rebalancing effect on the peri-urban agroecosystem inner complexity and environmental stability parameters.     

Artificial developed habitats can sustain plant communities similar to remnant ecosystems in the Tokyo megacity

Artificially developed habitats in urban ecosystems, known as novel ecosystems, have recently been underscored in terms of increasing urban green cover. However, patterns of changes in species diversity and composition in novel ecosystems over time remain poorly understood, making it unclear whether all novel ecosystems contribute to urban biodiversity. Here, we assessed how plant species diversity and composition in developed habitats changed over the years since the development of habitats (years since development) using a space-for-time substitution approach in the megacity, Tokyo, Japan. We established multiple survey transects at each study site to investigate the plant species diversity and composition. Using the ordination regression-based approach, we found that the plant species composition in developed habitats changed over the years since development and became similar to that in remnant habitats after approximately 130 years. We also found that the diversity of native plant species did not change whereas that of exotic species decreased with the years since development. Our results demonstrate the importance of developing new habitats for conserving urban biodiversity, while highlighting that exotic species can easily establish in newly developed habitats. Given that remnant ecosystems in urban areas are degraded by urbanization, the time required for novel ecosystems to become similar to remnant ecosystems is essential for predicting and conserving future urban ecosystems.     

质量平衡法估测树干呼吸的理论与应用

介绍质量平衡法的理论、估测方法及其应用,并对其进行评价.质量平衡理论认为:一段树干组织产生的CO2,应该是CO2通量的总和,包括通过树皮向外扩散的CO2释放通量、该段树干液流中的CO2运输通量(流入和流出液流的CO2浓度之差)及液流中的CO2储存通量(液流中CO2浓度在时间上的变化量).应用质量平衡法测定树干呼吸的关键是要估测树干内部的CO2通量,即液流中CO2的储存、运输和扩散.对于液流中CO2的估测主要有2种方法:1)用仪器直接测定木质部液流中的CO2浓度;2)通过测定树干液流停止流动或相对很低时(夜间)树干的CO2释放通量与液流流动时(白天)树干CO2释放通量的差值,间接估测木质部液流中CO2浓度.质量平衡方法提供了一个更为精确地估测木本组织呼吸的方法,其结果更为合理.