Leaf chlorophyll content as a possible diagnostic mean for the evaluation of plant nitrogen uptake from the soil

The influence of temperature, irradiance, and soil humidity on the nitrogen (N) concentration in some organs, chlorophyll in the leaves, N uptake and accumulation of dry matter in plants of winter wheat was investigated. In the plants grown under equal initial N supplement but in contrasting conditions of the evironment, the correlation between concentration of total N and chlorophyll in the leaves was absent. No interrelationship was found between concentration of total N in the leaves and accumulation of N and dry matter in the whole plants. There is a close correlation between chlorophyll in the leaves, accumulation of total N, and dry matter of the whole plant. It was concluded that chlorophyll is a more stable informative parameter for the estimation of the N uptake from the soil under different growth conditions than leaf N concentration.     

小鼠基因内含子中CpG岛和几个转录调控元件分析

内含子在基因转录调控中的作用已多次被实验报道,然而对其参与调控的普遍性还缺乏足够的理论支持。本研究利用计算分析方法,对小鼠基因内含子中的CpG岛（CpGisland）、TATA框（TATAbox）、CAAT框（CAATbox）以及GC框（GCbox）等元件的出现频率进行分析。结果发现,分别有56.01%、57.16%、65.88%和41.86%的第一内含子具有CpG岛、TATA框、CAAT框以及GC框,而它们在其它内含子中的平均出现频率则分别为14.07%、45.24%、49.91%和13.19%。即使考虑到不同位置的内含子,这些元件在第一内含子中的出现频率也显著高于它们在其它任何位置内含子中的出现频率。由于CpG岛、TATA框、CAAT框以及GC框均与基因的转录调控有关,据此推测小鼠第一内含子在基因转录调控过程中具有潜在的重要性。本研究结果为内含子参与转录调控提供了更多的理论依据。     

Does returning sites of historic peri‐urban waste disposal to vegetable production pose a risk to human health? – A case study near Manchester,UK

Urban waste disposal occurred on fenland to the west of Manchester, England, between 1900 and 1964. The reclaimed fenland, Chat Moss, is now used for mixed arable farming. A total of 1.92 Mt of waste including privy midden, street sweepings, clinkers and slaughterhouse refuse was incorporated into the moss resulting in a modified topsoil with raised pH and reduced organic matter content compared with the subsoil. Elevated levels of potentially toxic elements (PTEs) are observed in the topsoil beyond the typical depth of atmospheric contamination; Cd and As concentrations exceed soil guideline values (SGVs) at 1.8 and 43 mg/kg, respectively. Sequential extraction indicates that waste‐derived Pb, Zn and Ni remain predominantly in the residual fraction, whereas Cu was mainly organically bound. Arsenic was predominately found in oxide and organic matter fractions with Cd in carbonate, oxide, organic matter and residual fractions. Pot trials indicated limited uptake of PTEs by vegetables grown on the waste‐amended soil, with the exception of Cd uptake by lettuce (0.22 mg/kg FW) and Pb uptake by radish (0.16 mg/kg FW), which exceeded current EU limits of 0.2 and 0.1 mg/kg FW, respectively. Hazard quotients (HQs) identified no risks to adults from consumption of vegetables grown in these soils with the exception of lettuce consumption with a HQ of 1.4. Risks to children were slightly greater with HQs >1 for Cd in lettuce, spinach, carrots and onion, As in lettuce, parsley and onion and for Zn in spinach.     

广西农产品物流企业WLC品牌元素的选择研究

针对广西农产品物流企业的特点,从众多影响企业品牌建设与发展的因素中,采用AHP-TOPSIS模型选择确定品牌全生命周期阶段对品牌竞争力影响力度最大的品牌元素,以实现品牌的可持续发展。     

原子吸收光谱法测定青蒿中金属元素含量

使用HNO3-HClO4体系消解样品,采用火焰原子吸收光谱法测定5种不同来源青蒿(Artemisia annua L.)中的Mg、Fe、Mn、Cu和Zn含量.结果表明,青蒿中5种金属元素的含量大小依次为Mg＞Fe＞Zn＞Mn＞Cu,该法加标回收率在98.00％～104.00％,相对标准偏差(n=3)为0.51％～2.86％.该法快速、简便、灵敏、准确,可用于青蒿中金属元素的分析.     

使用JDBC实现自动气象站要素信息检索

介绍了使用JDBC实现自动气象站分中心站的气象要素信息检索，程序运用B／S体系结构，遵循MVC设计思想，采用Model2模式进行开发，为了提高程序的运行速度，在数据库中创建了存储过程。     

Estimating Trace Element Availability in Soils with a Seasonal Water Table using Commercially Available Protocols

The soil accumulation of metals and other elements as a result of human activities is a global concern. This investigation involves the use of commercially available extractions to estimate elemental abundance and availability. The need exists, especially in poor nations, to have cost-effective analytical capabilities to perform an initial screening of a soil resource to determine if a problem exists. Three extraction protocols are proposed: (i) an aqua regia digestion to estimate a baseline geochemistry, (ii) a pyrophosphate extraction to estimate elemental abundances associated with the soil organic fraction, and (iii) a water extraction to estimate the most available fraction. If the soil resource is impacted, then more refined and traditional methods are required to document the extent of impact for possible remediation. The three extraction protocols were applied to soils with little impact to illustrate the assessment potential for selected metals and p-block elements.     

Effect of Salinity Stress and Surfactant Treatment on Physiological Traits and Nutrient Absorption of Fenugreek Plant

Salinity is considered as a major abiotic stress affecting crop production in arid and semi-arid regions in the world. Surfactants can improve water-use efficiency in saline soils and improve crop yield. This study was conducted to evaluate the effect of salinity stress and surfactant treatments on photosynthetic pigments and nutrition elements of fenugreek in the Crop and Soil Science greenhouse at the Pennsylvania State University (University Park, PA, USA) in 2013. The experiment was conducted using a 5 × 3 factorial randomized complete block design with three replications. Factor A consisted of five salinity levels [0, 4, 6, 8, and 10 ds m^–1 sodium chloride (NaCl)] while factor B consisted of three nonionic surfactant levels (0, 1, and 3 ppm). The results indicated a stepwise reduction in photosynthetic pigments of fenugreek as salt stress increased, however, Peroxidase and polyphenol oxidase activity increased in fenugreek leaves as salinity stress increased. Levels of surfactant application had different effects on nutrient uptake. Some nutrient elements such as sodium, phosphorus, copper, manganese, and zinc content increased while others decreased at high salinity conditions. Surfactant application rate of 3 ppm at moderate and high salinity levels and 1 ppm at lower salinity levels had a good performance in enhancing the total photosynthetic and carotenoid activities in fenugreek.     

变频恒压供水在农村饮水安全工程中应用的调查

恒压供水比以往的供水方式节能环保了很多,笔者对几十个村进行调查,存在未能实现二十四小时供水和老百姓因用容器储水不当而出现水质最终被污染危险的安全问题,解决方法设备、先进技术这两部分是节能和更好利用水源的关键问题.     

驴奶中微量元素的测定

以驴奶为研究对象,测定了其中K、Ca、Na、Mg、Fe、Zn6种微量元素的含量,以期为驴奶资源的开发和利用提供一定的理论参考。