水稻施用植物生长促进菌效果初探

通过田间试验,对一种植物生长促进菌(PGPR)在水稻上的应用效果作了初步探讨。试验结果表明,PGPR制剂与化肥配合施用对水稻生长发育产生了显著的影响。与单施氮、磷、钾化肥相比,PGPR与化肥处理显著提高了水稻的株高、穗数、穗粒数、千粒重,比单施化肥和不施肥对照分别增产26.0%和53.9%。同时,PGPR处理提高了水稻的根系活力,并对灌浆速率产生了积极的影响。     

Effects of DHRS3 in C2C12 Myoblast Differentiation and Mouse Skeletal Muscle Injury

Myoblast differentiation is an essential process during skeletal muscle development. C2 C12 myoblast is a commonly used experimental model to study muscle cell differentiation in vitro. Dehydrogenase/reductase(SDR family) member 3(DHRS3) is a highly conserved member in short-chain alcohol dehydrogenase/reductase superfamily and has been shown to be involved in the metabolism of retinol. Previous experimental results showed that the expression of DHRS3 increased significantly during the differentiation of myoblasts differentiation. However, the effect of DHRS3 on mouse muscle cell differentiation was unclear. The objective of current study was to determine if DHRS3 affected muscle cell differentiation, and if DHRS3 was involved in muscle regeneration. Protein expression was determined by western blot and immunofluorescence analysis. The activation and inhibition of DHRS3 increased and decreased C2 C12 myoblast differentiation respectively, which indicated that DHRS3 could affect C2 C12 myoblast differentiation. DHRS3 expression was significantly changed during muscle regeneration, with the regeneration of muscle injury, the expression of DHRS3 tended to increase first and then decrease. It suggested that DHRS3 might be involved in muscle regeneration. In summary, this study confirmed the involvement of DHRS3 in C2 C12 myoblast differentiation and mouse skeletal muscle regeneration and provided a theoretical basis for further elucidating the molecular mechanism of muscle development.     

湖南三种不同嫩度工夫红茶香气品质比较分析

对湖南红茶标准样及安化群体种与黄金茶等三种不同嫩度红茶样进行了香气感官品质评价和成分分析,结果表明:芽头红茶样品中醇类含量占比最高,呈现出馥郁高长的鲜甜香;一芽一叶红茶样品中醇类、醛类、酮类和酯类含量居中,多表现为纯正较浓的甜香;一芽二叶茶样样本间差异较大,碳氢化合物和酯类化合物在标准样品中占比较高,其花香明显,在安化...     

祁连山东缘高寒草地植物群落叶绿素高光谱反演模型的建立

祁连山高寒草地是我国北方草地的重要组成部分,近年来退化较严重,导致其产量、质量下降.利用ASD地物光谱仪采集了祁连山东缘高寒草地植物群落光谱数据,并利用Person相关系数法、PCA主成分分析法和VIP变量投影重要性法等方法,筛选了与高寒草地植物群落叶绿素相关性较高的原始光谱波段与植被指数,通过多元逐步回归与多元线性回...     

基于RS的崇明岛土地利用变化及驱动力分析

对区域某时段内土地利用变化进行研究,并分析引起变化的驱动力因素,可以了解该区域土地资源利用的合理性,并为进一步制定符合土地资源可持续发展的经济发展规划,尤其为发展低碳产业提供科学依据。笔者运用遥感软件ENVI 4.8对崇明岛2000年、2005年、2010年3期Landsat ETM+遥感影像进行解译分类,对土地利用变化的特征和速率及驱动力因素进行分析。结果表明：崇明岛总面积不断增加,各土地利用类型的面积不断变化,表现出耕地及林地面积呈减少趋势,其中,林地降幅最大;建设用地、水体及未利用地面积呈增加趋势,其中,建设用地增幅最大;土地利用变化的速率不断提高。引起崇明岛土地利用变化的主要驱动力因素为社会经济因素,具体包括农业发展、人口增长及以工业为主的经济发展等;表现为碳源的土地利用方式面积减少,而表现为碳汇的土地利用方式面积则增加。     

QuEChERS-高效液相色谱法测定果蔬中多菌灵残留

建立了一种以高效液相色谱（HPLC）测定果蔬中多菌灵残留的方法,该方法采用QuEChERS技术为前处理方法,以乙腈作为提取溶剂,以PSA（Primary Secondary Amine,N-丙基乙二胺）和C18填料作为净化材料。试验结果表明:多菌灵标准品在0.1～10.0 mgL范围内线性相关系数为1.000;方法定量限为0.1 mg/kg（SN=10）;加标浓度为0.5和5.0 mg/L的平行5次测试结果相对标准偏差分别为2.98%和1.72%;0.1、0.5和5.0 mg/L 3个不同浓度的加标回收率在96%~110%之间。      

Evaluating eddy covariance method by large-scale weighing lysimeter in a maize field of northwest China

Accurate determination of evapotranspiration (ET) is useful to develop precise irrigation scheduling. Although eddy covariance (EC) is a direct method which is widely used to measure ET, its performance in arid region of northwest China is not clear. In this study, ET measured by EC (ET_EC) was compared with that by large-scale weighing lysimeter (ET_L) during the whole growing season of maize in 2009. Energy balance ratio was 0.84 for daytime fluxes, indicating that lack of energy balance closure occurred, so daytime ET_EC was adjusted by Bowen-ratio forced closure method. Compared to the corresponding ET_L, half-hourly daytime ET_EC was underestimated by 21.8% without the adjustment and 4.8% with the adjustment. Furthermore, nighttime ET_EC was adjusted using filtering/interpolation method. Mean error between half-hourly nighttime ET_EC and ET_L decreased from 30.2% without the adjustment to 10.3% with the adjustment. After such adjustment of day and night measurements, daily ET_EC was underestimated by 6.2% compared to ET_L. These results indicated that the adjusted ET_EC well matched with the ET_L. Moreover, the discrepancy of adjusted total ET_EC and ET_L was decreased to 3.2% after subtracting the overestimated ET by lysimeter resulting from irrigation and heavy rainfall events. Thus, after appropriate adjustments of observations, eddy covariance method is accurate in estimating maize ET in the arid region of northwest China.     

樱桃番茄运输包装件振动冲击性能试验

针对目前樱桃番茄储运过程中主要包装形式以及造成破损的情况,选择典型运输包装件,进行了正弦扫频、堆码强度、堆码扫频振动传递性能、垂直冲击和跌落试验。通过对单件包装件的扫频振动试验,测出单件的固有频率为26.61Hz;通过堆码强度试验,测出了包装件的最大堆码层数为9层。通过9层堆码扫频振动传递性能试验确定了底层、中间层和顶层包装件的固有频率分别为36.61、10.76和6.44Hz,得到了各层包装件振动加速度、振动传递率随时间的变化曲线,并探讨了固有频率和振动传递率峰值与堆码高度之间的关系。在此基础上,通过垂直冲击试验,测出了产品的脆值为89.58;通过跌落试验,测出了包装件最大允许跌落高度为580mm。     

东方蝼蛄膜翅表面形态与润湿性

利用扫描电镜分析了东方蝼蛄膜翅的表面形态.在OCA20型接触角测量仪上测量了水与东方蝼蛄膜翅展开表面各部位的接触角,分析了东方蝼蛄膜翅表面几何微结构与润湿性的关系.研究表明,东方蝼蛄膜翅展开后各部位的几何微结构各不相同,水与东方蝼蛄膜翅展开表面各部位的接触角平均值为94.4°～118.6°,表现出疏水性能.东方蝼蛄膜翅表面几何微结构与疏水性能的综合作用是其折叠后表面不沾土壤和水的重要机理.     

瓜类嫁接机上苗定位夹持装置的设计

设计了一种新型嫁接机上苗定位夹持装置,可实现嫁接苗的定位、断根和夹取功能。新型上苗定位装置由滑块摇杆收拢机构和夹取断根机构两个部分构成,针对幼苗定位连杆末端需形成包络轨迹将嫁接苗包住的农艺要求,进行机构的数学建模和仿真优化,得到了最佳的结构参数。以“拿铁砧”葫芦苗为对象取苗进行试验,其定位夹持的成功率达93%以上,符合自动嫁接需求。