中国鹅掌楸混合芽的发生和形态建成

本文继中国鹅掌楸花芽分化细胞形态学观察的研究之后,我们又系统观察了混合芽从发生至花器官建成的形态变化、芽的类型和分布以及芽端生长点的细胞形态学,试图为鹅掌楸属的系统学研究、植物性分化的生理学研究和种子品质的遗传学研究提供基础资料和理论依据。     

香菇芦笋复合饮料的研制

利用香菇和芦笋的下脚料加工配制的复合饮料具有香菇和芦笋和芦笋特有的香味,口感纯正,效果很好。     

十和田近等基因系糙米锌含量QTL定位

以十和田为轮回亲本,丽粳2号为供体亲本培育出糙米锌含量近等基因系群体BC5F6为材料,从遍布水稻12条染色体上的600对引物中筛选到一个与糙米锌含量有关的SSR标记RM4608.根据其在水稻染色体上的位置,结合PCR扩增结果又发现了与糙米锌含量有关的4个SSR标记(RM19491,RM19489,RM6119和RM19487).用MAPMAKER3.0软件做出了这5个标记的连锁群,最后采用混合线性模型定位法找到了糙米锌含量的QTL位点.QTL分析结果显示:该位点位于6号染色体上RM4608和RM6119标记之间,贡献率为5%,为新发现的与糙米锌含量有关的微效基因位点,暂命名为qZINC-6.同时与糙米铬和镁含量有关的QTL位点也被发现,其中糙米铬含量QTL位于标记RM19489和RM19491之间,贡献率为9%,是一个主效基因;糙米镁含量QTL位于标记RM4608-RM6119之间,是一个微效基因,贡献率为4%.     

烤烟生物复合肥的应用研究进展

烟草作为中国一种重要的经济作物,而施肥是烤烟栽培的关键技术。通过对近年来生物复合肥在烤烟生产上的应用研究进展的综述,指出了目前烤烟生物复合肥研究中存在的问题。     

Italian ryegrass establishment by self-seeding in integrated crop-livestock systems: Effects of grazing management and crop rotation strategies

We evaluated the re-establishment of an Italian ryegrass pasture by self-seeding on a no-till integrated crop-livestock systems (ICLS) in the southern region of Brazil. This work is part of a long-term experimental protocol initiated in 2003. We tested the effects of various management practices, such as summer crop systems (soybean vs. maize–soybean rotation), stocking methods (continuous vs. rotational) and grazing intensities (low vs. moderate), on Italian ryegrass pasture establishment. In addition, we tested resilience of the system by testing pasture's ability to re-establish following a year without seed head production. The experiment consisted in the rotation, on the same area, of Italian ryegrass pasture grazed by sheep during the winter and up to the end of the grass production cycle, and soybean or soybean-maize grain crops rotation cultivated during the summer. The pasture established itself by self-seeding since 2005. Data were collected in 2011 and 2012 stocking season. The soybean summer crop, continuous stocking and low grazing intensity, all positively affected the production of reproductive tillers in 2011. Grazing intensity in 2011 strongly influenced early vegetative tiller densities (before crop harvest) in 2012. However, none of the grazing intensity or the stocking method treatments affected herbage mass at the end of pasture establishment in 2011 or 2012. On the other hand, the soybean summer crop positively affected pasture establishment, both in term of tiller densities and herbage mass at the end of pasture establishment. The removal of all seed heads in 2011 (preventing seed production) resulted in the total failure of pasture establishment in 2012. Overall, Italian ryegrass establishment by self-seeding relies on the annual replacement of the soil seed bank. This experiment demonstrated that under various stocking methods, moderate grazing intensity and maize or soybean summer crop, Italian ryegrass pasture establishment by self-seeding remains successful even when the stocking periods extended up to the end of the grass production cycle. Self-seeding with moderate grazing intensity ensures successful pasture establishment, reduces labour and costs and allows to increase the stocking period and so animal live weight gain over the grazing season.     

Identification of cultivars of pasture legumes (Centrosema macrocarpum,C. pubescens and C. sp.n.) by acid polyacrylamide gel electrophoresis of cotyledons storage proteins

Summary An electrophoretic procedure was developed for storage proteins which can discriminate cultivars of forage legumes, Centrosema macrocarpum, C. pubescens and C. sp.n. Proteins extracted from cotyledons were separated in 10% polyacrylamide gel containing 10% sucrose. Electrophoretic patterns are presented to illustrate the results that can be obtained with the procedure described. Cultivars of all three species were distinguishable based upon the variation in their acid soluble seed proteins.Joint publiccation of the Department of Food Science, University of Manitoba (No 101) and Centro Internacional de Agricultura Tropical-CIAT.     

青贮玉米混合青贮研究进展

玉米是我国重要的青贮饲料来源,蛋白质含量较低是制约其饲喂价值的主要问题。混合青贮可通过原料间成分的互补性以及发挥微生物的互作效应实现青贮饲料营养品质的均衡与提升。本文综述了玉米与高蛋白牧草、副产品和青贮添加剂混贮的研究进展,分析了现阶段的优势与不足,展望了我国玉米混贮未来的研究方向,为我国玉米混贮应用提供参考。     

基于混合遗传算法的谐波齿轮传动优化设计

以谐波齿轮传动体积最小为优化设计目标,建立了混合离散变量优化设计数学模型。引入混沌移民算子,对基本遗传算法进行了改进,以维持群体的多样性,提高全局收敛能力。提出了一种设计变量的离散化处理方法,结合染色体编码的修正技术,在遗传算法中染色体按离散化后的设计变量进行离散搜索。开发了混合离散变量优化的改进遗传算法程序,给出了谐波齿轮传动的混合离散变量优化设计实例,所得优化设计参数符合设计规范,不需进一步处理就可直接用于制造。     

农民工未来阶级、阶层走向解析

"民工"从语词上界定可以理解为:农民和工人双重身份,本文放在传统农业向现代农业转变的大背景下,着重考察了游离在城乡之间的农民工主题身份的认定,及其未来的阶级、阶层走向,按照断裂社会的运作逻辑,经过分化重组的当下社会必定会出现新的阶级、阶层.这些阶级、阶层与传统阶级、阶层有什么区别和联系,农民工如果被假定为工人阶级而客观存在.那么这些生活在城市里农民能否获得市民身份的认同?对这些问题的回答有利于我们走出"城乡二元格局"的困境,有利于构建更加稳定、和谐的社会主义新农村.     

弧齿锥齿轮齿面闪温分布特性分析

在Blok闪温公式的基础上,计算混合弹流润滑下的齿面平均摩擦因数,修正了公式中的齿面平均摩擦因数,提高了计算精度。同时,通过计算弧齿锥齿轮沿齿面啮合点的切向速度、赫兹接触带半宽和载荷分配系数,提出了混合弹流润滑下弧齿锥齿轮沿接触轨迹和全齿面的闪温公式。经算例分析表明,非正交弧齿锥齿轮副沿接触轨迹闪温的最大值位于啮出轨迹中部,全齿面闪温的最大值在大轮节锥与齿根之间的齿面中部,这些部位最容易发生胶合。