基于都市农业背景下的农业科技在农业生产中的作用

农业基础竞争力不强、比较优势逐步丧失等问题逐步成为我国今后一个时期农业面临的最大挑战,科技创新作为农业发展的重要支撑,必须发挥其引领作用,为农业转型升级增加新动能。北京国际都市农业科技园作为现代农业科技示范园区,紧紧围绕农业科技创新驱动,统筹国内外农业科技创新资源,在农业生产过程中实现科技全覆盖。该研究以北京国际都市农业科技园为例,从种子到餐桌的角度分析了农业科技在农业生产中的应用,以期为农业转型升级提供借鉴。     

鄱阳湖湿地灰化苔草群落物种多度分布格局沿水分梯度的变化

为揭示鄱阳湖湿地苔草群落的构建机制,选择灰化苔草(Carex cinerascens)群落作为研究对象,通过设立3条样带调查不同水分梯度的群落物种多度,选用断棍模型(BSM)、生态位优先占领模型(NPM)、优势优先模型(DPM)、随机分配模型(RAM)和生态位重叠模型(ONM)5个生态位模型对群落种-多度关系进行拟合,结果表明,1)灰化苔草群落可按土壤水分划分为高湿度、中湿度和低湿度3组,分别对应从湖边、湿地中间和湿地边缘的梯度分布;2)从高到低的水分梯度上,灰化苔草群落的物种数先增加后降低,优势种多度逐渐增加,物种多度分布曲线由相对平缓变为陡峭;3)高湿度灰化苔草群落物种多度分布格局的最佳拟合模型为BSM,中、低湿度的理想模型转变为NPM。研究认为,水分条件的变化是灰化苔草群落物种多度分布格局改变的主因,随着水分梯度降低,群落构建的生态学过程由随机生态位变为生态位优先占领。研究为鄱阳湖湿地多样性保育和生态功能管理提供了理论参考。     

小麦显性雄性不育基因的发现与利用——太谷不育小麦鉴定总结

1972年,山西省太谷县水秀公社郭家堡大队高忠丽同志在大田发现一株不育小麦。几年来该大队与一些研究单位协作搞三系配套,主攻保持系,至今还未筛选出有完全保持能力的品种或有完全恢复力的品种。1976年,我组从郭家堡大队引进这份材料。经过三年研究,通过细胞学观察,并结合多年的数据分析,初步确定这个太谷不育小麦是“无花粉     

太谷核不育小麦雄性败育过程的细胞形态学研究

本文总结了由 Tal 基因控制的太谷核不育小麦的败育特点;描述了从造孢细胞一直到单核花粉期的多种退化现象:花粉母细胞早期衰退,减数分裂不正常,生长发育不整齐,几种败育现象并存于一朵小花乃至一个花药之中。不论败育早晚,形态各异,其特点都是在很短时间之内就急剧而彻底地解体,最后药室空空,仅剩下两层空肥化的药壁。作者从     

固体氧化钴pH电极的研制

本文制备了一种可用于溶液pH值测定的固体氧化钴印刷电极。该电极可在2～12pH范围内呈现出良好的Nernst响应。文中就氧化钴的合成方法及印刷电极的制备工艺参数对电极响应行为的影响进行讨论。     

双波灯诱集棉铃虫的效果评价

通过对１９９６ ～１９９８ 年３ ａ 的双波灯与杨树把诱集棉铃虫的结果比较分析,双波 灯诱蛾具有诱蛾数量多、蛾峰明显、雄蛾多于雌蛾等特点。可以将之用于棉铃虫的预测预报。     

Reproductive performance and offspring quality of Chinese mitten crab Eriocheir sinensis (H. Milne-Edwards) females fed an optimized formulated diet and the razor clam Sinonovacula constricta

After feeding female Eriocheir sinensis on an optimized formulated diet or fresh razor clam Sinonovacula constricta for 7 months, their reproductive performance and offspring quality were compared. To evaluate diet nutrient contents, the proximate, fatty acid and amino acid compositions of the formulated diet and the razor clam were analysed. The nutritional value of the diets was determined by assessing survival, gonadosomatic index (GSI) and hepatosomatic index (HSI) of female crabs from both diet treatments, together with the percentage of females that spawned, total egg production per female and fecundity (number of eggs g^?1 female wet weight). Furthermore, the quality of eggs and newly hatched larvae from the two dietary treatments were determined using the following parameters: egg diameter, wet weight and dry weight, hatchability, proximate and fatty acid profile of eggs, larval carapace length, resistant to starvation and osmotic shock, larval survival and development to the zoea II stage. Higher protein, phospholipids (PL) and amino acids (AA) contents were found in the razor clam while the formulated diet contains higher levels of ash, total lipid (TL) and 18:1n‐9, 18:2n‐6 and 22:6n‐3 fatty acids. Although female crabs fed the two different diets showed similar reproductive performances, newly hatched zoea I larvae produced by the crabs fed the formulated diet had significantly longer mean carapace length and shorter development time to the zoea II stage under identical culture condition (P<0.05). Moreover, dietary fatty acid appeared to have more significant effects on the fatty acid composition of the hepatopancreas than it did on mature ovaries or eggs. This suggests that the fatty acid profile of mature ovaries is indicative of the specific fatty acid required for ovarian development in E. sinensis. In conclusion, our results show that the optimized formulated diet developed in this laboratory can totally replace the razor clam, a broodstock food widely used in E. sinensis hatcheries in China. This encouraging result should facilitate more reliable hatchery production of this important aquaculture species.     

基于Pro/E的渣浆泵水力部件开发

基于三维实体造型软件Pro/E对渣浆泵水力部件进行计算机辅助设计的二次开发,考虑到固体颗粒对水力部件的影响,运用两相流理论设计了渣浆泵水力部件及其相关几何参数.在Windows XP操作系统平台上,借助Visual C＋＋6.0语言开发环境以及MFC可视化对话框技术,利用Pro/E的二次开发工具Pro/TOOLKIT及其相关接口函数,对渣浆泵水力部件设计进行可视化Pro/E Wildfire 2.0系统开发,渣浆泵水力部件的设计子菜单被嵌入在Pro/E的主菜单中.针对水力部件的设计实例,该软件通过渣浆泵相关子菜单弹出设计界面,在对话框中输入渣浆泵的设计参数,可实现水力部件的几何尺寸计算过程,并根据几何尺寸自动生成叶轮、副叶片、蜗壳、前后盖板等水力部件的三维造型.     

气相色谱内标法测定乳油中的受控溶剂

本文以毛细管气相色谱内标法测定乳油中的甲醇、甲苯、二甲苯、N,N-二甲基甲酰胺和萘5种有害溶剂。采用Stabilwax-DA毛细管色谱柱(30m×0.32mm,0.25μm)及氢火焰离子检测器,以正癸烷为内标物计算含量。测定结果不受样品中有效成分的干扰,5种目标物的线性关系良好,样品3个水平的加标回收率在98.72%~102.70%之间,相对标准偏差3.0%。对市售25种乳油产品的实际检测应用表明,该方法简便快速,准确可靠。