Spring Barley Responses to Row Spacing and Fungicide Triadimefon in Regions with a Short Crop-growing Season

Aspects of intensive management practices such as high-yielding cultivars, narrow-row spacings and fungicide treatments could potentially increase cereal yields in regions with a short crop-growing season and occasionally dry and hot weather. A field experiment was carried out at McGill University, Canada for three years (1987 to 1989) to test the effects of triadimefon (1-[4-chlorophenoxy]-3,3-dimethyl-1-[1H-1,2,4-triazol-1-yl]-2-butanone, or Bayleton, a trade name) fungicide (0 vs. 140 g a.i. ha⁻¹) and row spacing (10 vs. 20 cm) on the yield components, yield and other agronomic traits (spike emergence, days to maturity, leaf disease and plant height) of spring barley ( Hordeum vulgare L.) cv. Cadette, Laurier and Leger. A cultivar by row spacing interaction resulted in a 11 to 13.5 % increase in grain yield due to narrow rows for Laurier in two out of the three years and up to 16 % for Leger in one year. Over the three years grain yields were on average increased 6 to 12 % due to use of the narrower row spacing. Fungicide application to barley at the early heading stage effectively controlled leaf diseases without influence on yield components or grain yield. Our results indicate that some components of intensive management such as narrow row spacing can be applicable in regions with a short crop-growing season.     

昆明小鼠ES细胞的分离培养及鉴定

[目的]摸索一种适合昆明小鼠ES细胞分离培养的方法,以提高昆明小鼠ES细胞的建系率。[方法]分别采用5种方法分离ICM和ES细胞集落,摸索了以BMSCs作为饲养层时,丝裂酶素处理的合适时间。[结果]连续消化法要明显好于其他4种方法。MMC处理BMSCs 1、1.5、2 h时效果较好,3个时间点无显著差异(P>0.05)。mMEF作为饲养层与BMSCs作为饲养层时获得5代ES细胞相比差异不显著(P>0.05)。[结论]连续消化法分离ES细胞效率较高,饲养层采用MMC处理1~2 h的BMSCs饲养层或常规mMEF饲养层对昆白小鼠ES细胞无明显影响。     

哺乳动物胚胎干细胞分离与培养的研究进展

从胚胎干细胞的来源、分离方法和饲养层细胞等方面,总结了胚胎干细胞分离与培养在近年来所取得的进展。     

Beyond catchment considerations in the conservation of lotic biodiversity

• 1. The history of river conservation has largely focused on preservation of the physical and structural properties of lotic ecosystems in an attempt to ensure safe and potable water supplies for human consumption. Such strategies are increasingly being implemented at the catchment or basin scale.
• 2. Although these reflect positive developments in the conceptualization of conservation issues pertaining to lotic systems and provide the logical economic, sociological and/or political units for management, we question whether they represent the appropriate scale for the protection of lotic biodiversity and biological processes. We argue that this requires considerations that extend beyond the protection of physical habitat to ensure protection of population processes.
• 3. Although many species can be successfully conserved using the catchment as the basic management unit, many others cannot. We review evidence from genetic studies of aquatic populations to examine movement in relation to catchments, recognizing that organisms with poor dispersal characteristics during their life cycles exhibit a high degree of genetic structure, whilst organisms with robust dispersal characteristics typically exhibit a homogeneous genetic structure.
• 4. Species with poor dispersal characteristics are more easily conserved at the catchment level, whereas those with high dispersal characteristics can only be safely conserved at bio‐regional supra‐catchment levels.
• 5. Modern technological advances aimed at redistributing water from areas with perceived surpluses to those with perceived deficits (inter‐basin water transfers), demonstrated to transfer organisms between historically isolated catchments, pose a potential threat to the conservation of biodiversity by mixing genetically distinct populations and hence altering evolutionary processes and pathways.
• 6. If our arguments hold, then it appears that conservation authorities need to reappraise the current dominant paradigm of the catchment as the basic unit for conservation and management, and incorporate broader, strategic landscape planning in water resource management.

Copyright © 2003 John Wiley & Sons, Ltd.     

猪ICM注人囊胚获得嵌合胚的研究

以湖北白猪囊胚为ICM供体,杜洛克猪囊胚为受体囊胚,进行嵌合胚的研究.采用免疫外科和显微外科两种方法,分离184枚供体囊胚的ICM.用酶将ICM分散,而后注入到受体囊胚的囊胚腔中,共获67枚嵌合胚,经体外短期培养,其中35枚嵌合胚恢复,恢复率为52.2%.将恢复的嵌合胚分别移入5头与供体囊胚猪同步的受体母猪子宫内,两头受孕,其中一头维持到分娩.产仔4头,但未见毛色嵌合现象.     

国有企业集团内部资本市场配置效率实证研究

采用沪市A股国有上市公司2010年数据,运用相关分析方法,从四个视角分析国有企业集团内部资本市场配置效率。理论分析和实证研究结果表明:(1)国有企业集团内部资本市场能够缓解融资约束;(2)国有企业集团内部资本市场并未异化为控股股东利益侵占途径,集团总部与成员企业之间以及成员企业内部的代理问题是导致内部资本市场低效的主要原因。     

Towards obtaining long term embryonic stem cell like cultures from a marine flatfish, Scophtalmus maximus

Culturing pluripotent embryonic stem cells represents a unique model system for in vitro studies of embryo cell growth and differentiation, and represents a connection between in vitro and in vivo manipulation of genes. To further develop and refine stem cell technology for marine fish, we have established cultures of embryonic stem cells isolated from turbot blastulas. The pluripotent nature of our turbot-ES-like cells was supported by their morphology and elevated levels of alkaline phosphatase enzyme activity, their ability to remain undifferentiated for a prolonged culture period, their spontaneous differentiation potential in vitro and their ability to form embryoid bodies (EB) in response to changes in the extracellular environment. In addition, we show that turbot ES like cells express Oct-4 required for the maintenance of pluripotency of ES cells. Cells from 100 blastulas (>10⁵ cells/well) were seeded into gelatine coated 24 well cell culture clusters. The cells were polygonal in shape, with dense cytoplasm and large nuclei. The ES-like cells formed colonies within 24 h following seeding, multilayered in a pyramidal fashion, with maximum cell densities in the middle. The cells proliferated vigorously when seeding densities were high and the cells still had not attached to the gelatine-coated surface. Most of the cells became attached to the surface 48 h following seeding. Attached cells grew more slowly and 20% of the plated colonies could be kept stable for 60 days. Eventually, most of the cultures showed extensive differentiation or died. Only a few cultures (4–5%) survived prolonged culturing (>2 months). The cells were stained for alkaline phosphatase activity, a marker of pluripotency and showed intense staining. More specific, turbot ES like cells in culture expressed Oct-4, detected by immunofluorescence staining. Changing the medium conditions by adding retinoic acid and removing LIF, the proportion of embryoid bodies in our cultures increased. ES-like cells as well as fresh, intact fertilised eggs where successfully cryopreserved. ES cells from the cryopreserved eggs could be isolated and seeded into cultures, forming colonies like the cells from freshly fertilised eggs. Also cryopreserved ES-like cells could be successfully plated. The prolonged survival of these cryopreserved cells has not yet been investigated. The establishment of in vitro cultures of turbot ES-like cells represents a new experimental model for marine flatfish. This revised version was published online in July 2006 with corrections to the Cover Date.     

兔类胚胎干细胞的体外培养

为了确立兔类胚胎干细胞(ESCs-like)体外培养方法,研究探讨了兔囊胚形成环境与饲养层细胞对内细胞团(ICM)增殖、ICM原代集落形成以及集落碱性磷酸酶(AKP)阳性率的影响,并在MEF和REF饲养层上进行了兔ESCs-like的体外培养。结果显示,去除透明带桑葚胚在体外具有较高的囊胚发育率和囊胚贴壁率(P<0.05),体外发育囊胚ICM原代集落的AKP阳性率却显著低于体内发育囊胚(P<0.05);与MEF饲养层相比,REF饲养层上ICM原代集落的形成率显著偏低(P>0.05),但原代集落的AKP阳性率却显著高于其余各组(P<0.05);MEF饲养层与REF饲养层均支持兔ESCs-like的传代培养,但F3代后MEF组中ESCs-like的集落形成率显著高于REF组(P<0.05)。     

纤维含水率控制系统的人机接口改进

叙述了中纤板纤维干燥过程含水率控制系统人机接口的一种改进方式，采用中断二维直读键盘结构，与并行接口芯片8255A接口；利用LED显示器驱动芯片ICM7228扩展LED显示器，把各参数分时显示改为单独实时显示，显示参数直观方便，便于操作人员观察。