奶牛的应激特性

应激是指环境因素突然发生的变化,或因疾病、药物、管理不当等的影响引起奶牛生理上的不适应而造成生产性能降低的现象。应激反应的程度,通常,奶牛比一般牛强烈,泌乳牛比升奶牛强烈,升奶牛比降奶牛强烈,成年牛比幼龄牛强烈。空怀又不产奶的牛以及育成牛应激反应最轻。     

不同栽培树形对油橄榄品种果实产量的效应

Longnan City in Gansu Province is the largest base of olive production in China. In the olive orchard locating in Wudu District of Longnan City, thirty trees were sampled each of three cultivars, ‘Leccino’, ‘Chenggu32’, ‘Ezhi8’, with monoconical and vase training system. After planted with density of 5×6 m in 1992, each sample tree was investigated to determine the yield fresh fruit in five different years. The results of survey and analysis showed that there were significant differences of fruit yield among 5 years and 3 cultivars. Different canopy shapes yielded some effect on fruit setting rate and yield of different cultivars in different years. During first fruiting period in the fourth/sixth year after planting, fruit setting rate and yield of ‘Leccino’ with monocone were more 6.7% and 0.15 kg than those with vase and those of ‘Ezhi8’ and ‘Chenggu32’ with vase were more 20%, 10% and 0.18 kg, 0.09 kg than those with monocone. With the increase of tree age, fruit set and yield of ‘Leccino’ and ‘Ezhi8’ with vase was more than those of monocone. In 2011, average yields per tree of ‘Leccino’ and ‘Ezhi8’ with vase were more 13.35 kg and 6.85 kg than those with monocone. And the highest yield per tree of ‘Leccino’ with vase was 75 kg, more 16 kg than that of monocone. Fruit trees with yield over 35 kg of ‘Leccino’ and 25 kg of ‘Ezhi8’ with vase accounted for 80% and 46.7%, more 40% and 30.01% than those of monocone. It was concluded that vase training system would produce higher yield of ‘Leccino’ and ‘Ezhi8’ and its effect and advantages were gradually prominent with increase age. As for ‘Chenggu32’, monocone got a slightly higher yield than that of vase and in 2011 fruit trees with yield over 15 kg accounted for 25%, more 8.34% than vase. The difference between two training system of this cultivar was not obvious.     

黑色素细胞中过量表达miR-137对TYRP-1和TYRP-2的影响

【目的】证明miR-137通过调控MITF而间接影响小鼠黑色素细胞TYRP-1和TYRP-2的表达,从而影响黑色素的生成。【方法】通过细胞转染技术在细胞水平过量表达miR-137,对黑色素细胞中黑色素含量进行了测定,经RT-PCR以及western blot检测转染后细胞TYRP-1和TYRP-2在mRNA和蛋白水平的变化。【结果】黑色素含量明显减少,在mRNA水平,TYRP1显著降低至0.4倍,TYRP-2显著降低至0.6倍。在蛋白水平,TYRP-1显著降低至0.61倍,TYRP-2显著降低至0.73倍。【结论】过量表达miR-137会通过调控MITF而使黑色素细胞TYRP-1和TYRP-2的表达量降低,从而揭示了miR-137通过调节TYRP-1和TYRP-2的表达间接调控了黑色素的生成。     

赤狐生境选择研究进展

总结了赤狐生境选择的研究方法和研究内容,概括了影响赤狐生境选择的主要因素,并探讨了赤狐生境选择的灵活性及赤狐和与其同域分布的动物种的共存机制.最后,提出了赤孤相应的保护措施.     

保康县生态公益林建设现状与对策

本文结合县情林情,对湖北省保康县生态公益林建设现状进行了深入探索与分析,针对存在的突出问题提出了对策和建议,为加快建设绿色襄阳示范区、都市襄阳后花园建设提供生态保障.     

SOX5影响小鼠皮肤黑色素细胞MITF-M表达和黑色素生成

旨在探讨SOX5在小鼠皮肤毛色中的作用。本研究随机选取出生后12d的C57BL/6品系黑色、棕色、灰色小鼠各3只,采用实时荧光定量PCR、Western blotting和免疫组织化学方法对SOX5在黑色、棕色和灰色小鼠皮肤中的表达差异进行分析;并构建SOX5真核表达载体;运用体外转染的方法,转染小鼠黑色素细胞并检测与色素形成相关基因的表达水平,同时测定黑色素含量。结果表明:1)SOX5在不同毛色小鼠皮肤中均有表达,SOX5在黑色和灰色小鼠皮肤中mRNA和蛋白相对表达量高于棕色小鼠皮肤,均差异极显著(P0.01);且其主要表达部位为毛囊外根鞘。2)转染组与空载组相比,MITF-M、TYR、TYRP1、TYRP2、PMEL、OA1表达量均显著(P0.05)或极显著(P0.01)升高,黑色素含量也极显著增加(P0.01)。3)过表达MITF-M对SOX5存在负反馈作用。综上表明,SOX5通过调控MITF-M影响色素的生成进而参与毛色的形成。     

白蜡虫的危害及防治

结合几年的细致观察,该文对白蜡虫的分布、形态特征、习性、发生规律、危害症状、危害方式及防治措施做以综述。几年来的防治实践,证明灭扫利、敌杀死防治效果最好,具有极强的触杀作用,喷药后一般15~40 min蜡丝断条,若虫从枝条上脱落死亡,无污染,对人畜安全。     

新疆棉花亏缺灌溉叶面积指数模拟研究

建立了充分灌溉和亏缺灌溉条件下新疆棉花叶面积指数的动态模拟模型。模型以基于beta函数的每日热效应为时间尺度,在考虑土壤水分胁迫效应的基础上,使用Logistic函数的一阶导数描述叶面积指数的变化速率,叶片衰老过程同样采用Logistic函数的一阶导数,并假设从初花期开始发生。该模型还考虑了土壤水分胁迫和温度对叶片衰老的加速效应。最后使用石河子棉花灌溉试验观测结果对模型进行了参数率定、验证和敏感度分析。验证结果显示:充分灌水条件下叶面积指数的均方根误差(RMSE)为0.22 m2/m2,残差聚集系数(CRM)为-0.01;20%和40%亏缺灌溉条件下叶面积指数的RMSE和CRM分别为0.37 m2/m2、-0.05和0.23 m2/m2、0。此外,叶面积指数的模拟值与实测值间R2为0.96。说明该模型准确地模拟了新疆棉花叶片全生育期的动态变化过程。敏感度分析结果表明,在充分灌水条件下,叶片潜在衰减面积、叶片日最大增加面积和衰减面积、初花期开始时间是影响模型的主要参数。     

油橄榄的高接换优及管理技术

高接换优技术是对低产劣质油橄榄进行改造提高产量和品质的有效途径之一。采用插皮接法,成活率达98?以上。低产树和实生树经过高接换优2~3 a恢复树冠,第3年开始试花试果,第4年株产可达4~8 kg。本文着重论述了砧木选择、良种接穗的采集和贮藏、嫁接方法时间和高接后的放风、除萌、松绑、绑支柱及整形修剪、间种绿肥等一系列管理措施。     

影响主轴部件旋转精度的分析及改善方法

本文主要分析滚动轴承、主轴和轴上零件等对主轴部件旋转精度的影响因素及提高主轴部件旋转精度的相应措施。