MINERALOGY AND CHEMISTRY OF A TRANSVAAL BLACK CLAY TOPOSEQUENCE

Moralistic soils (vertic and non-vertic black clays) were sampled along a 200 m top sequence in the Transvaal Highveld, South Africa. The Milk wood soil on the upper part of the margalitic top sequence has an Al horizon which lacks both slickensides and self-mulching properties but has strong blocky structure, the others are all self-mulching (i.e. Vertisols). The Vertisols differ in some morphological properties such as the absence (Mngazi series) and presence (Arcadia series) of pedogenic calcite accumulation, both overlying decomposed dolerite, whereas the third member from a red-black centenary sequence is calcareous with a gleyed subsoil horizon. Chemical and XRD analysis suggest that the clays of the Vertisols comprise mainly a partly chloritized iron-rich smectite with Ie > Mg + Al in the octahedral layer (and interlayer positions), while in the upland Milkwood soil intergradient halloysitic clay occurs in addition to a more‘open’structured chloritized iron smectite. The mineralo-chemical results and the geomorphic data suggest that the genesis of these soils is controlled primarily by the internal soil water regime.     

胡蜂益害关系的评价

胡蜂总科除少数类群分布中心在东洋区的热带区域外,其余全世界都有分布。到目前为止,世界已知种达5000余种,其中蜾赢就有2000种。这些胡蜂是一种很好的资源,在热带、亚热带地区开发利用胡蜂资源具有较广阔的前景。例如,在生物防治、医药、食品和化妆品等方面。     

RP-HPLC测定不同产地白蔹药材中没食子酸的含量

[目的]建立白蔹药材中没食子酸的RP-HPLC含量测定方法,为白蔹药材的质量标准研究提供依据.[方法]采用Dikma Diamon-sil C18(250×4.6mm,5μm)色谱柱,以乙腈-0.2％磷酸(3∶97)为流动相进行等度洗脱.流速为1.0 ml/min,柱温为30℃,检测波长为270 nm.[结果]没食子酸检测浓度在3.15 ～ 202 μg/ml的范围内与峰面积积分值呈良好的线性关系(R2 =0.999 9);平均回收率为102.8％,RSD为1.15％.[结论]该方法快速,重现性好,准确度高,操作简便,可用于白蔹药材的质量控制.     

苗期湿害胁迫下不同基因型芝麻的反应差异研究

通过苗期湿害处理,研究了24份不同基因型芝麻叶片相对电导率、含水量和保水力等性状变化。结果显示,湿害胁迫下芝麻叶片相对电导率显著增加,叶片含水量有所下降,叶片保水力降低明显,不同基因型间存在较大差异。根据相对电导率计算而来的伤害度与叶片含水量、保水力呈极显著负相关,叶片含水量与保水力呈极显著正相关。聚类结果显示,参试材料明显聚为耐湿与不耐湿2大类,耐湿类群包含刚果野芝麻、竹山白、165、中芝13和赣芝13号。     

基于分子标记的江西省芝麻地方种质遗传多样性分析

为进一步评价“第三次全国农作物种质资源普查与收集行动”中江西收集的132份芝麻地方种质资源的遗传多样性,明确其遗传基础和群体分类特点。利用筛选获得的28对简单重复序列(simple sequence repeat,SSR)引物和26对相关序列扩增多态性(sequence-related amplified polymorphism,SRAP)引物组合对132份江西芝麻地方种质进行遗传多样性研究。结果显示,28对SSR引物共扩增DNA条带265条,其中,多态性条带221条,比例为83.40%,平均每对引物扩增的DNA条带和多态性条带分别为9.46条和7.89条。26对SRAP引物组合扩增得到DNA条带和多态性条带分别为601条和268条,多态性比例为44.59%,每对引物可扩增9~36条DNA条带和2~23条多态性条带,平均每对引物扩增的多态性条带为10.31条。132份种质的遗传相似系数为0.598 2~0.960 7,平均为0.813 5,可见总体的遗传多样性不丰富。6个不同地理区域的芝麻遗传相似系数从北至南呈逐渐下降趋势,赣南区域的地方种质遗传多样性较赣北区域丰富;不同粒色类型比较结果显示,其他粒色芝麻类型(黄色、褐色、黄褐色、红褐色等)的遗传多样性最丰富,其次是白芝麻类型和黑芝麻类型。聚类分析结果表明,来源不同的芝麻种质呈区域性聚集特点,种质间的遗传相似性与地理分布距离有一定的关联,来自赣北和赣东的芝麻种质资源因在亲缘关系上更近而被聚为一类,其余区域聚为一类,这与总体聚类结果基本一致。不同粒色类型中,区域来源不同的种质均相互交错,其聚类结果与地理来源无直接关联。在今后芝麻种质收集工作中,应注重赣南与其他粒色种质的利用,扩展江西乃至我国芝麻品种遗传基础。     

Application of multivariate statistics in model experimental analysis of air cushion towing of 4-suction anchor platform

This paper coducts model tests on a 1∶20 scaled model of four-suction anchor platform. The acceleration, the internal air pressure, the bottom water pressure of the suction anchors and towing force of the suction anchor platform are determined in series of towing combinations with different wave direction, wave velocity, wave period, towing velocity, towing points, towline length and tilt angle. Cluster analyses are used to classify the combinations of towing and factor analyses one used to analyze the mechanical characters. The correlative matrix is obtained which can reflect the correlation of mechanical characters. The factor analysis results show that 85% the total variance is attributed to the former six factors, and the factor scores of the towing combinations was obtained to find the most disadvantageous combinations and the mechanical characters which can lead to the disadvantageous results. The analysis results can be used for consulting the practical application.     

两种基于芦苇秸秆还田的改良措施对崇明东滩围垦土壤理化性质和微生物呼吸的影响

在崇明东滩湿地公园设置了3块实验田,研究基于芦苇直接还田（处理Ⅰ）和堆肥后还田（处理Ⅱ）的处理措施对盐碱土壤的改良效应以及对土壤微生物呼吸和植物生长的影响,并通过主成分分析法评价仅考虑传统土壤肥力指标及加和了土壤微生物呼吸和植物生物量等碳收支指标的土壤综合改良效应。结果表明,两种模式都能显著提高土壤的养分。总氮、总磷和总钾均显著高于对照（P〈0.05）,有机质较对照分别提高10.8%（P=0.053）和10.9%（P=0.052）;地上生物量为对照的344%（P=0.000）和167%（P=0.000）,但土壤微生物呼吸仅分别较对照提高14%（P=0.085）和43%（P=0.001）。主成分分析结果显示仅考虑传统的土壤肥力指标,对照、处理Ⅰ、处理Ⅱ的综合得分分别为-0.641、0.260、0.381,加和土壤微生物呼吸与植物生物量后综合主成分得分为-1.011、0.644、0.367。这表明按传统评价指标,处理Ⅱ是较好的改良模式,但加和了土壤微生物呼吸与植物固碳量等碳收支指标后,处理Ⅰ得分高于处理Ⅱ,因此这是一种相对低碳化的改良模式。     

MAGNETIC RESONANCE IMAGING OF SPONGY DEGENERATION OF THE CENTRAL NERVOUS SYSTEM IN A LABRADOR RETRIEVER

A 7-month-old, neutered female Labrador Retriever was evaluated for tetraparesis and subtle cerebellar dysfunction. Clinical signs progressed over a period of 6 weeks to severe ataxia, hypermetria, intention tremors, and finally non-ambulatory tetraparesis. On magnetic resonance imaging of the brain there were large, bilaterally symmetrical, ovoid lesions in the region of the deep cerebellar nuclei that were hyperintense on T2-weighted and proton density images and hypointense on T1-weighted images. There were similar but smaller bilaterally symmetrical lesions present within the thalamus. Euthanasia was performed and lesions consistent with the previously described spongy degeneration of Labrador Retrievers were identified. This disease and its relation to similar human heritable leukodystrophies are discussed.