乡土物种补播对青藏高原高寒草甸群落稳定性的影响

为了探究高寒草甸天然草地补播乡土物种对草地群落稳定性的影响，本试验以垂穗披碱草（Elymus nutans）、异针茅（Stipa aliena）、中华羊茅（Festuca sinensis）、溚草（Koeleria cristata）、星星草（Puccinellia tenuiflora）、扁蓿豆（Melissitus rutenica）、冷地早熟禾（Poa crymophila）为试验材料，设置5种混播组合，于2017年在青海省贵南县天然草地上进行补播。试验采用方差比率法（Variance ratio，VR）、M.Godron贡献定率法（Contribution law）以及生物量稳定性分析方法，结果表明：5种组合补播后使得群落联结性降低、生物量稳定性增大，群落整体稳定性增强，正向着稳定方向发展；5种组合中，组合D （扁蓿豆+星星草+垂穗披碱草+异针茅+溚草）的生物量稳定性最大，是对草地恢复最有效的物种组合。本试验筛选出了对草地生态修复最有效的物种组合，为草地保护及利用提供了科学依据。     

深松施用有机肥对玉米不同器官钾含量的影响

为了明确深松结合施用有机肥对玉米不同器官钾含量的影响,在大田条件下,设常规旋耕(T_1,CK)、深松(T_2)、深松施用有机肥(T_3) 3个处理,测定了玉米大喇叭口期、灌浆期、成熟期不同器官的钾含量。结果表明:T_3处理的玉米茎钾含量在大喇叭口期和灌浆期均为最高,其中大喇叭口期指标值与T_1处理差异显著,而在收获期低于其他2个处理但差异均不显著;叶片钾含量全生育期始终高于T_1处理、低于T_2处理,其中与T_2处理差异均不显著,但在灌浆期指标值明显高于T_1处理;苞叶钾含量始终低于T_1处理,与T_2处理相比灌浆期较高、收获期较低,但差异均不显著;轴钾含量在灌浆期最高、收获期最低,与其他2个处理差异均达到了显著水平;灌浆期和收获期玉米子粒钾含量均最高,且与T_1处理差异均达到了显著水平,在灌浆期指标值也明显高于T_2处理。综合分析认为,深松施用有机肥有利于提高玉米生育前期各器官尤其是玉米子粒的钾含量。     

体外产气法评价全株藜麦与全株玉米混合青贮饲料饲用价值

为提高全株藜麦的饲料化利用率，寻找其与全株玉米的最佳青贮比，试验共设全株藜麦与全株玉米比为100：0，90：10，80：20等11个组合进行青贮发酵，发酵60 d后测定各组青贮料的体外产气发酵指标，使用灰色关联度分析筛选出最佳青贮比例。结果表明，体外发酵至36 h时，各处理组GP趋于稳定，体外发酵减弱接近停止；全株藜麦与全株玉米比例为90：10时，该青贮饲料组合的粗蛋白（CP）和粗脂肪（EE）含量显著高于其他各组（P<0.05），乙酸（AA）、总挥发性脂肪酸（TVFA）含量以及氨态氮（NH₃-N）浓度显著高于其他各处理（P<0.05）。分析表明，全株藜麦与全株玉米比例为90：10时，混合青贮饲料的营养品质和产气发酵特性综合表现最好，可作为优质混合青贮饲料在家畜养殖中推广使用。     

国内高架桥绿化及研究现状

从高架桥区的生态环境、适生种类的选择以及高架桥绿化的养护管理、景观配置模式四个方面对国内的高架桥绿化及研究现状进行了分析和探讨,指出了存在的问题和解决方法,并对高架桥绿化的前景进行了展望.     

辽北地区芋头栽培技术

芋头为我国南方所特有的蔬菜栽培品种,在高纬度的辽北地区从未栽培过.2001年铁岭市龙山乡七里村村民张德良在乡农科站科技人员的支持下,引种南方的"毛芋"栽培试种1 334 m2,获得成功,每穴产芋头1.5 kg,多的达到3～4 kg.产芋72 397.5 kg/hm2.2003年全村栽培面积达到7 hm2,产芋头65 655 kg/hm2.上市销售个头小的每2.00/kg元,个头大的每3.00/kg元,效益十分可观.下面就芋头的栽培技术及芋头的经济价值作以介绍.     

基于单片机的脉码传输仪设计

以单片机为核心,采用软件、硬件相结合的方法,充分利用单片机的硬件中断资源,实时响应地面的声波逻辑脉冲,分离其接收和发射逻辑。同时该仪器以地面声波逻辑为工作时序,分时采集模拟道数据、脉冲道数据及向地面传输PCM数据。该脉码传输仪既能完成PCM3506的全部功能,又能监测仪器工作环境的温度及测井套管接箍的压力。     

Relationship between the intracellular calcium concentration changes and left ventricular hypertrophy and function in the spontaneously hypertensive rats

AIM:To elucidate the relationship between the intracellular calcium concentration changes and left ventricular hypertrophy and function in the spontaneously hypertensive rats (SHR).METHODS:Intracellular free calcium concentrations were measured by Fura 2 methodology and left ventricular function quantitated by cardiac catheterization in 20 SHR aged 10, 22, and 34 weeks and 20 age-matched Wistar-kyoto (WKY) rats.RESULTS:(1) The systolic blood pressure(SBP), intracellular calcium concentrations and left ventricular mass / body weight index (LVM/BW) were significantly higher in all three age groups of SHR than the corresponding groups of WKY; (2) Compared with age-matched WKY groups, the peak left ventricular pressure descending rate(-dp／dt_max) decreased while left ventricular relaxation time constant (τ)increased significantly in SHR aged 22 and 34 weeks. The peak left ventricular pressure ascending rate(dp／dt_max) and the left ventricular contractility index were significantly increased only in the 34 weeks SHR; (3) Intracellular calcium concentrations showed a positive correlation with LVM/BW,SBP,-dp／dt_max and τ(r=0.47-0.83,P<0.01)and a negative correlation with dp／dt_max and the left ventricular contractility index (r=-0.46,P<0.05 and r=-0.81, P<0.01).CONCLUSION:Intracellular calcium overload is one of the potential mechanisms in the induction of left ventricular hypertrophy as well as of systolic and diastolic dysfunction.     

Cell proliferation and nestin expression in cortex and SEZ of MCAO rats

AIM:To explore the effect of brain ischemia injury on cell proliferation and nestin expression in cortex and subependymal zone (SEZ).METHODS:Using a local brain ischemia model(MCAO), BrdU positive cells of cortex and subependymal zone (SEZ), also nestin positive cells, were observed by immunohistochemistry.RESULTS:BrdU and nestin positive cells in SEZ of MCAO rats were obviously increased. In cortex, only nestin positive cells were observed.CONCLUSION:Neural stem cells in SEZ and cortex were activated after brain ischemia, it may be related with neural recovery after brain ischemia injury.     

The application of atomic force microscope in clinic diagnosis of erythrocytes

AIM: To investigate the application of atomic force microscope (AFM) in clinic diagnosis. METHODS: Topographic images and some parameters of large range field and microstructures of erythrocytes in the blood of normal subjects, lung cancer and myelodisplastic syndrome (MDS) patients were examined by atomic force microscope. RESULTS: Many clear topographic images of many erythrocytes, single erythrocyte, and microstructure of erythrocyte membrane surface were obtained. Many erythrocytes in lung cancer patients were found to change into echinocytes. One erythrocyte had 10-20 protuberances, most of which, with a mean width of 589. 0 nm and a length of 646. 7 nm, were on the edge of cells. The protuberances on the center of echinocytes are lodged and embedded. The erythrocytes of MDS patients were biconcave in shape. Many apertures with different diameters of tens to hundreds nanometer appeared on the surface of cell membrane. CONCLUSIONS: AFM can be widely applied in clinic pathological inspection, including quantification of cells, obtainment and comparison of many parameters (such as diameter, thickness, volume, surface, surface area/volume ratio), observation of topograph of single cell, and observation and comparison of membrane surface microstructure of cells, and so on.     

Selection and amplification of the liver stem cell subset from rat bone marrow cells with a medium containing cholestatic serum in vitro

AIM: To explore the feasibility of direct separat and selective enlargement of the bone marrow-derived liver stem cells (BDLSC) from bone marrow cells with a culture system containing cholestatic serum in vitro. METHODS: Bone marrow cells of rats were cultured with selective media containing 2%, 5%, 7% and 10% cholestatic rat serum, respectively. The BDLSC were then induced to proliferate with the addition of hepatocyte growth factor (HGF) on the firth day. BDLSC were characterized using immunocytochemistry and RT-PCR for lineage markers, glycogen staining and urea synthetic assay for functions 2 weeks later. RESULTS: Bone marrow cells were unble to form colony in the presence of 2% cholestatic serum and apopotosis appeared gradually in 7% or 10% cholestatic serum. The BDLSC survived in the medium containing 5% cholestatic serum while the other types of cells did not. The survival cells proliferated with a high speed during the second week and then formed hepatocyte-like colony-forming units (H-CFU). Cells in the H-CFU expressed the characteristic proteins of fetal hepatocytes. Furthermore, they had glycogen storage and urea synthesis functions, two of the critical features of hepatocytes. CONCLUSION: The selective micro-environment effectively selected BDLSC from the bone marrow cell, and will be a new way to provide an abundant source of donor hepatocytes for clinical cell therapy.