不同刈割处理对白三叶及杂草盖度的影响

夏秋季在白三叶种子田用5cm、8cm、10cm三种留茬高度与15d、30d、45d三个间隔时间组合为9个刈割试验处理,对白三叶及杂草盖度的变化进行了研究。结果表明,刈割能有效控制杂草,提高白三叶盖度;间隔时间是促进白三叶生长、控制杂草的主效因子;留茬8cm、间隔时间30d处理的白三叶盖度由43.25%升至73.00%,杂草盖度由83.75%降至17.25%。     

肉仔鸡腹水综合症的营养调控

本文对肉仔鸡腹水综合症的几种主要诱发因素(包括遗传、饲养环境和饲料营养等)和日粮营养(包括能量、蛋白质和氨基酸、维生素和微量元素、L-肉碱和泛醌等)调控研究进行了综述,重点介绍了L-肉碱或/和泛醌的调控作用可能是通过维持线粒体呼吸链酶活,改善线粒体功能,增强能量代谢和抗氧化功能,从而降低肉仔鸡对腹水综合症的敏感性.     

三江白猪OB基因多态性及其与繁殖性能的相关性分析

试验利用PCR-RFLP法研究了三江白猪OB基因3 469位点的多态性及其与繁殖性能的相关性。结果表明:OB基因经HinfⅠ酶切后出现3个条带,表现为3种基因型(AA型、AB型和BB型)和2个等位基因(A和B),A等位基因为优势基因,基因频率为67.6%;头胎产活仔数BB型极显著高于AA型(P<0.01),BB型高于AB型,AB型高于AA型,但差异都不显著(P>0.05),BB基因型比AB型和AA型的头胎产活仔数分别高出1.65头、2.19头;不同的基因型对前5胎最高产仔数的影响差异不显著(P>0.05)。     

以番鸭呼肠孤病毒σC表达蛋白为抗原的ELISA检测方法的建立

将鸭呼肠孤病毒小外壳dC蛋白编码基因克隆于原核表达栽体pET32a上，经EcoRⅠ和SacⅠ双酶切鉴定及序列分析，获得了重组质粒pET32a-σC，转化DH5a大肠埃希氏菌感受态细胞后，经SDS—PAGE和Western—blotting分析，融合蛋白能够与番鸭呼肠孤病毒感染康复鸭血清发生特异反应；以0．15mmol／L IPTG诱导，5h后融合蛋白σC表达量可达高峰，分子质量为50ku；融合蛋白纯化后被用作包被抗原，建立了检测鸭血清中呼肠孤病毒抗体的间接ELISA，经对检测条件优化，最佳包被浓度为5μg／mL，标准阳性血清的最适稀释倍数为1：40。用该方法对50份鸭血清样品进行了检测，与琼脂扩散抗体检测法相比，ELISA具有良好的特异性和敏感性。     

云南白三叶种子田杂草及其季节变化规律

经取样调查及田间观察,云南白三叶种子田中共有76种杂草,分属26科。主要杂草分别为春季杂草:荠菜、藜、苕子;夏季杂草:野黍、荞叶、十字马唐、牛膝菊、尼泊尔蓼、希签;秋季杂草:牛膝菊、荞叶、夏枯草、十字马唐、尼泊尔蓼、野黍;冬季杂草:荠菜、夏枯草、藜、鼠麴草。     

转化生长因子-β对胚泡着床的调节作用

转化生长因子-β是一多效性生长因子，参与调节子宫内膜的局部微环境，对妊娠的维持起着重要的局部调节作用。在妊娠子宫内膜广泛分布，其蛋白质表达及基因表达受类固醇激素等母体因素的调控，本文就转化生长因子-β对胚泡着床的调节作用所做的研究进行综述。     

纳米材料在汽车涂料中的应用

纳米材料是指结构单元(结晶体)至少在一维方向上受纳米尺度(1~100 nm)调制的各种固体材料,其尺寸处在原子簇和宏观物体交界的过渡区域。利用纳米粉体材料较强的紫外光反射特性、抗老化,加之能在涂料干燥时很快形成网络结构,同时增强涂料的强度和光洁度。在涂料中添加纳米材料可提高涂层的表面强度、耐磨性,能使涂层产生丰富而变幻莫测的色彩效果和具有除臭功能。     

小麦苗期抗纹枯病鉴定方法的改良及抗病品种筛选

Wheat sharp eyespot, caused by Rhizoctonia cerealis and R. solani, is a soil-borne fungal disease, which poses a great threat to wheat yield. In order to increase the identification efficiency of wheat sharp eyespot resistance, an improved method of rapidly identifying wheat sharp eyespot resistance was established by inoculating wheat seedlings with diseased wheat grains in greenhouse. To verify its reliability, four standard materials and 96 wheat varieties from Huanghuai wheat region were used for resistance assessment to sharp eyespot. Meanwhile, the resistance to Rhizoctonia solani of aforementioned materials in the field was identified by traditional methods. The results showed that the correlation coefficient between the four repetitions of the improved method ranged from 0.735 to 0.825, and the correlation coefficient between the average number of repetitions and the traditional method was 0.630. The results of wheat sharp eyespot resistance identification in Huanghuai wheat area showed that 66 wheat varieties were susceptible, accounting for 68.8% of tested materials. This indicated that the resistance of wheat varieties in Huanghuai wheat area to sharp eyespot was poor on the whole and needed to be improved urgently. At the same time, eleven wheat varieties which showed resistance to sharp eyespot at seedling and adult stages were screened, which include Zhengzhou 8998, Beijing 841, Handan 94-5316, Jimai 32, Jinmai 50, Jinmai 54, Longmai 157, Lumai 23, Shanhe 6, Shi 02-1 and Xinmai 18. Therefore, this study provides a method for identification of wheat sharp eyespot resistance at seedling stage, by which the resistance of wheat varieties to sharp eyespot can be quickly and efficiently identified. Furthermore, selected resistant materials provide important material resources for wheat sharp eyespot resistance breeding in Huanghuai wheat region and even in China.     

醚唑种衣剂对小麦幼苗生长及抗病性相关酶活性的影响

 本文研究了醚唑(Difenoconazole)种衣剂、敌萎丹悬浮种衣剂(Dividend 150FS)分别处理小麦种子后对小麦幼苗生长、膜脂过氧化产物丙二醛(MDA)以及与植物抗病性相关的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和多酚氧化酶(PPO)酶活性的影响。结果表明2种药剂处理均能使小麦幼苗叶绿素含量、株高、根长和百株鲜重显著增加,幼苗体内MDA积累减少,SOD、POD、CAT和PPO活性显著提高,但对可溶性蛋白的含量无明显影响。说明醚唑种衣剂包衣处理小麦种子具有促进小麦幼苗生长发育、延缓小麦衰老和诱导小麦产生抗病性的作用,为防病增产奠定良好基础。     

人工草地绵羊系统优化研究Ⅷ家畜疫病防治优化探讨

文章以发病规律研究和流行病学调查、防疫卫生程序化和制度化、新产品新方法试验研究和推广应用、家畜自身适应机能的建立、疫病监控等几方面来论述人工草地家畜系统疫病防治优化对策.