在黑土型退化草地上提高牦牛生产力的途径   总被引：2，自引：0，他引：2  

马玉寿  郎百宁  杨海明  马玉莲 《中国草地学报》1998,(4):61-63

青藏高原是我国牦牛的主产区,但近年来黑土型退化草地的发生与发展直接威胁着我国牦牛业的发展.通过对退化草地的调查分析,认为不合理的放牧制度是引起草地退化的主要原因,草地退化又引起牦牛生产力的下降,据此提出了通过建立人工、半人工草地和加强牦牛的科学饲养管理、改善本地区生产环境、保持牦牛-高寒草甸系统持续发展的设想.  相似文献   

百脉根大田种子生产的技术研究     

刘法涛  杨志忠  条了汉  杜雷全  哈德力别克  徐振成  何和托拜 《中国草地学报》1998,(1):21-23

在准噶尔盆地北缘海拔640m台地灌溉区新垦荒地上,通过对加拿大里奥百脉根6年的种子生产并结合小区试验,总结了整地、播种期、播种密度、灌溉、调节灌溉、施肥、收获种子、切割松耙等行之有效的方法,保证了大田种子生产丰产丰收,具有可靠、实用的推广价值.  相似文献   

球根鸢尾的病毒鉴定及试管脱毒成球技术   总被引：7，自引：0，他引：7  

袁梅芳 《园艺学报》1998,25(2):175-178

对上海地区球根鸢尾进行了病毒病害调查。经检测初步确定球根鸢尾普遍存在鸢尾重花叶病毒、鸢尾轻花叶病毒、水仙潜隐病毒３种病毒的复合侵染。对带毒种球进行茎尖组培脱毒,得出了茎尖诱导成芽、芽成球及小球生根的培养基配方。将组培苗在试管苗、成球苗、移栽苗等不同时期进行病毒检测,结果表明,小于１．０ｍｍ的茎尖诱导的幼苗可脱去上述３种病毒。  相似文献   

中椒10号的选育     

杨桂梅  张宝玺 《中国蔬菜》1998,1(5):11-0

中椒１０号系以９００１３－３和７８－１－１两个自交系配制而成的微辣型一代杂种,熟性早,早期产量比对照品种增加２．４％～１２．５７％,结果性好,抗ＴＭＶ,中抗ＣＭＶ。一般每６６７ｍ２产２５００～３５００ｋｇ,平均单果重３０．９～４２．５ｇ,果实长羊角形,果面光滑,颜色绿,肉质脆嫩,味微辣,品质佳,果实商品率高。已在北京、天津、河北、东北、安徽、四川及广东、广西、海南等南菜北运基地推广,面积达４８００ｈｍ２。  相似文献   

合抱类型大白菜抗TuMV材料的选育     

苏学军  张焕家  杨衔美  李化银 《中国蔬菜》1998,1(1):6-0

试验选用对ＴｕＭＶ具有不同抗性的８个大白菜高代自交系,配制了“抗×抗”和“抗×感”的４个合抱类型的杂交组合,采用单交法和系谱定向选择,结合苗期人工接种鉴定和田间自然诱发鉴定的抗性筛选技术,筛选出２６份合抱类高抗ＴｕＭＶ新材料 【英文摘要】 Four combinations of heading Chinese cabbage inbred lines resistant or susceptible to TuMV were made to screen resistance to TuMV and typical ovate head type which has leaf tip closing on the top,but not overlapping. By pedigree method,induiduals from each segregation generation were identified for resistance and head type. After four generations,26 inbred lines with resistance and ideal headtype were obtained.   相似文献   

机械加工工艺技术的误差与原因探究     

沈阳 《湖南农机》2017,44(2)

随着综合国力的日益提升,中国的经济实力和技术实力都有了显著的增长.但当前,我国机械工业快速发展面临的阻碍越来越大,其中,机械加工工艺的技术误差是一个重要影响因素,因此当前对机械加工工艺的技术误差进行研究和探讨有着重要意义.文章将简单介绍机械加工工艺并对其技术误差的出现原因进行分析研究提出几点改进的意见,期望能对机械工业的持续发展有所帮助.  相似文献   

基于屈服强度的X80钢管100％SMYS试压的可行性     

杨锋平  宫淑毓  冯耀荣  罗金恒 《油气储运》2013,32(5)

高强度试压是国内外管道试压的普遍趋势.为研究我国X80钢管100％SMYS(最小屈服强度)试压的可行性,以西气东输二线西段为例,应用概率统计方法,分析了X80直缝钢管和螺旋缝钢管管材试样屈服强度的分布特征,并研究了实物屈服强度和管材试样屈服强度的差异.结果表明:X80直缝钢管和螺旋缝钢管试样的屈服强度分布均符合正态分布,X80直缝钢管屈服强度性能优于螺旋缝钢管,钢管实物屈服强度比管材小试样屈服强度高10％～15％.以100％SMYS试压导致母材屈服概率小于1％为目标,根据管材试样屈服强度概率分布特征及试样与实物屈服强度的差异,得出X80钢管可进行100％SMYS试压的结论.  相似文献   

Biomass evaluation of concealed insect pests at parasitism based on allometric scaling laws     

Xiao-yi Wang  Yan-long Tang  Ji-fang Lu  Zhong-qi Yang 《Phytoparasitica》2013,41(4):435-441

In general, it is difficult to evaluate host resource utilization of parasitoids by examining the biomass of concealed wood borers at parasitism, because the larval tissues of parasitized hosts observed in field surveys are often almost completely consumed. This work explored a precise and convenient method for evaluating the biomass of concealed wood-boring insect pests after they are parasitized. Allometric scaling laws were used to determine mathematical relationships between larval weight and other size variables in two host insects: the emerald ash borer [EAB], Agrilus planipennis Fairmaire, and the oak long-horned beetle [OLB], Massicus raddei (Blessig). These insects are hosts of the parasitoid Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae). Our results showed that body weight among different instars was significantly different for both host species, with greater overlap between neighboring instars. Mean larval weight had a highly significant exponential relationship with instar number. EAB larval weight showed a highly significant power relationship to body length and width, width of the prothoracic plate, peristoma width, urogomphus length, and anteriormost width of the urogomphus. Significant power relationships were also observed between OLB larval weight and body size parameters (including body length, length of the mesothoracic spiracle, width of the prothoracic plate, distance between the main ocelli, and mandible length). These findings indicated that host biomass could be easily calculated if any one size variable could be measured at the time of parasitism. Allometric methods provide a precise means of evaluating time-specific biomass of concealed wood borers.  相似文献   

甜菜碱含量的测定方法比较     

杨雪  王洪荣  邹益东  朱建泉 《饲料工业》2013,(7):48-51

甜菜碱含量的测定方法有很多种,包括酸碱滴定法、紫外分光光度法、高氯酸非水滴定法、离子色谱法等。各种方法均有其优缺点,综合考虑,离子色谱法与非水滴定法的测定结果较好。为比较这两种方法哪种更准确、更方便,设计如下实验。选取5种含量不同的甜菜碱产品,分别用非水滴方法和离子色谱法测定5种产品的甜菜碱含量。实验结果表明,离子色谱法测定的甜菜碱含量与真实值较接近,非水滴定法测定的甜菜碱含量比真实值偏高。  相似文献   

Improvement of wood properties by composite of diatomite and “phenol-melamine-formaldehyde” co-condensed resin     

ZHANG Ming  XU Yang  WANG Shu-liang  SHI Jun-you  LIU Chang-yu  WANG Cheng-yu 《林业研究》2013,24(4):741-746

We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three...  相似文献