Environmental assessment of boreal rivers using fish data – a contribution to the Water Framework Directive

Abstract A fish‐based assessment method was developed to estimate the ecological status of boreal rivers. Electric fishing data were collected from 902 rapids, together with information on the land use, channel modification and water chemistry. Discriminant function analysis was used to select fish variables that most correctly classified the undisturbed reference sites and human impacted sites into exact classes. The relationship between the level of human alteration and fish metrics was examined. Five metrics were selected for the index: the number of fish species, proportion of sensitive species, proportion of tolerant species, density of cyprinid individuals and the density of age‐0+ salmonids. The value for each metric (between 0 and 1) was calculated according to a point estimate for classical probability. The index is used to estimate the ecological classification of rivers according to the EU Water Framework Directive.     

The Prospects of Tissue Culture and Genetic Engineering for Strawberry Improvement

Abstract

Strawberry shoot meristem cultures have been used for producing virus-free strawberry plants. Plantlet regneration from leaf mesophyll protoplasts, and Agrobacterium tumefaciens mediated genetic transformation, mark the beginning of strawberry improvement with biotechnologies. The use of biotechnological tools has a greater potential in producing strawberry plants with traits such as early maturation, frost and disease resistance, mite and nematode resistance, high yield, better quality, suitability for mechanical harvesting, shipping ability, ellgaic acid content, aroma compounds and cost-effective micropropagation. Gene identification and mapping with RFLPs or RAPDs would be desirable. Transgenic strawberries should be tested for their quality before releasing to the consumers.     

Germination-enhancing and zinc-sparing roles for selenium in broccoli

Large areas of China have soils low in both available selenium (Se) and zinc (Zn). In order to investigate whether Se supplied as either selenate or selenite can increase germination and growth compared with low-Se controls we used broccoli, an important vegetable with anticancer effects, especially when biofortified with Se. Broccoli was grown under both Zn adequacy and Zn deficiency to determine whether interactions between these minerals affect plant growth. Selenite and selenate at a wide range of doses increased the speed and extent of germination. Both inorganic Se forms increased early root and shoot growth at low concentrations, with selenite having a stronger effect than selenate. A sand culture trial showed a similar growth increase due to low-dose Se under Zn deficiency but not under Zn adequacy. Conversely, at high Se levels, the results provided evidence from biomass, water use, photosynthesis and gas exchange that broccoli growth was inhibited at high Se levels, with selenite being more toxic than selenate. In this broccoli trial, the two Se forms were equally effective in increasing leaf Se concentration, whereas in most plants selenite is largely converted to organic Se forms and stored in the roots. This study suggests that Se, supplied either as selenate or selenite, may improve germination and growth in broccoli, especially on Zn-deficient soils. Field trials conducted on soils which are very low in both plant-available Se and Zn are needed.     

Histopathology of Hematopoietic Tissue in Channel Catfish,Ictalurus punctatus,with Anemia

Outbreaks of anemia (CCA) in channel catfish, Ictalurirs punctatus, in Mississippi occur predominantly during spring and fall. Between October, 1990 and May, 1991, twenty-seven cases of CCA were submitted to the Mississippi Cooperative Extension Service-College of Veterinary Medicine Fish Diagnostic Laboratories. Histologic lesions were identified in the head and trunk kidneys of all affected fish. The head kidney contained less than 25% immature hematopoietic tissue in 3 of 22 cases (14%). 25-50% immature hematopoietic tissue in 7 of 22 cases (32%), and greater than 50% immature hematopoietic tissue in 12 of 22 cases (54%). The trunk kidney contained less than 25% immature hematopoietic tissue in 5 of 27 cases (18%), 25-50% immature hematopoietic tissue in 15 of 27 cases (56%), and greater than 50% immature hematopoietic tissue in 7 of 27 cases (26%). The histopathologic findings noted in cases of CCA from Mississippi affect primarily the hematopietic tissues of the head and trunk kidneys.     

深化图书馆改革是增强文化活力的重要基石———初论图书馆事业在新时期国家发展中的战略地位

建设社会主义文化强国，关键是增强全民族的文化活力。为增强文化活力，就要深化文化体制改革，解放和发展文化生产力，发扬学术民主，艺术民主，为人民提供广阔文化舞台，让一切文化创造源泉充分涌流。而全面深化图书馆改革就属于深化文化体制改革这一战略规划的重要组成部分．具有不容忽视的战略地位，它必将为增强中华民族的文化活力、建设文化强国做出自身应有的贡献。     

浅议文化造园

首先分析当前文化造园存在的一些问题,包括漠视园林文化和歪曲传统文化的现象,继而指出文化造园需要了解场地、尊重历史,其发展与丰富依赖于人与风景在时间长轴上的共同作用、不断积淀；最后以南宁孔庙植物景观和贵港龙蝠山庄假山的设计为例,简明阐释了在园林设计过程中如何结合实际、因地制宜,有效传承、发扬中国传统园林植物文化和山水文化.     

连续式真空干燥机在鱼粉加工中应用研究

研究了连续式真空干燥机在鱼粉加工中的工艺过程、工艺结构和工作原理。鱼粉加工中采用连续真空干燥机具有明显的优势,可以减少高温对鱼粉蛋白质的氧化,提高鱼粉蛋白质的含量,提升鱼粉品质,使其在市场竞争中占有优势。     

滨水环境景观设计研究——以湖州太湖旅游度假区为例

湖州市是一座江南古城,有着浓厚的文化底蕴.湖州太湖旅游度假区位于湖州市境内,其区域内河道网络纵横交错,产生了众多的桥梁和滨水地带.为进一步提升湖州滨湖度假区环境品质,增加度假休闲氛围,打造国内一流休闲旅游度假区,现对滨湖休闲景现带的景观设计理念进行研究探讨.     

The rumen ciliates of greater kudu Tragelaphus strepsiceros (Pallas) from South Africa and Zimbabwe with a description of one new species

Eighteen species of the family Ophryoscoiecidae, representing three genera, and three species of the family Isotrichidae representing two genera, were found in the rumina of kudu from the Republic of South Africa and Zimbabwe. One new ophryoscolecid Entodinium carinatum is described. Certain aspects of the taxonomy of Diplodinium archon, Entodinium longinucleatum and Entodinium dilobum are discussed     

根瘤农杆菌介导的水稻转基因方法的优化研究

[目的]优化根瘤农杆菌介导的水稻转基因方法。[方法]通过对经典水稻转基因方法的优化和改进,高效获得转基因水稻苗。[结果]使用成熟胚,采取升汞灭菌,侵染时农杆菌的OD600值为0.1时,转化效率最高,较原方法提高约23%。[结论]该研究为以根瘤农杆菌介导的水稻转基因研究提供了技术参考。