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181.
P. J. Randall 《Journal of plant nutrition》2015,38(2):212-223
Winged bean [Psophocarpus tetragonolobus (L.) DC] plants, line UPS31, were grown in pots of sulfur (S)-deficient soil in a glasshouse without added S or with five levels of added S. The seed was inoculated with rhizobia (Bradyrhizobia sp. strain CB756) and plants were later given additional mineral nitrogen (N). Harvests of shoots were made at 39 and 78 days after sowing (DAS). Shoot dry matter yield, total S (ST), S reducible by hydriodic acid (SHI) – a measure of sulfate – and N were determined. At 78 DAS, the critical concentration (at 90% maximum yield) of ST in shoots was 0.9 mg S g?1 dry matter and in young leaves was 1.4 mg S g?1 dry matter. Plants with these concentrations or below would be considered S-deficient. The usefulness of critical concentrations of SHI or ratios of SHI/ST, and N/ST as indicators of S status is discussed. 相似文献
182.
A. M. Rautengarten J. L. Schnoor S. Anderberg K. Olendrzynski W. M. Stigliani 《Water, air, and soil pollution》1995,85(2):737-742
Simultaneous soil acidification and deposition of heavy metals is a major concern for forest and agricultural soils of the Black Triangle region of East Central Europe including southern former East Germany, northern Bohemia of the Czech Republic, and southern Poland. The objective of this project was to develop historical and future projections of acid and heavy metal deposition to soils (As, Cd, Pb, Zn) and to produce a preliminary map of soil sensitivity to cadmium pollution and uptake by crops. Ultimately, we wish to assess the relative hazard and recovery times of soils to metals deposition in the region. Emission and deposition data bases obtained from several models developed at IIASA were linked using the Geographical Information System ARC/INFO to produce soil maps of sensitivity to cadmium mobility based on metals deposition, soil type, soil texture, organic matter content, and acid deposition. RAINS 6.1 (Alcamo et al., 1990) was utilized to produce maps of acid deposition for EMEP grids (150 km x 150 km). The largest amount of acid load is deposited in southern East Germany. Sulfur deposition in that area was 10–12 gS/m2/yr in 1990, and S+N deposition exceeded 8000 eq/ha/yr. But the hot spot for metals deposition is further to the east, in the Silesia area of southern Poland. The TRACE2 trajectory model of Alcamo, Bartnicki, and Olendrzynski (1992) was used to estimate cumulative metals deposition since 1955 with scenarios to 2010. Pb has improved over Europe since 1970 when depositions in the Ruhr River Valley of West Germany exceeded 60 mg/m2/yr. But cadmium deposition in southern Poland (Katowice and Krakow) has now accumulated to 60–70 mg/m2 by atmospheric deposition alone. During base case simulations from 1955–87, approximately 1.8 mg/kg Pb and 0.12 mg/kg Cd have been added to the mixed plow-layer of 30 cm. If these emissions continue indefinitely, the accumulation of metals will become problematic for agriculture and the food chain. 相似文献
183.
Ukonmaanaho L. Nieminen T. M. Rausch N. Shotyk W. 《Water, air, and soil pollution》2004,158(1):277-294
The concentrations and vertical distribution of Cu, Ni, Zn, Pb and As were studied in four different ombrotrophic peat bogs with varying heavy metal loads at Hietajärvi, Outokumpu, Harjavalta and Alkkia in Finland. At each site a peat sample (15 cm × 15 cm × 100 cm) was taken using a Titanium Wardenaar corer, and the samples were cut into 5 cm slices. Dried and milled samples were determined by X-ray fluorescence (XRF). The mean concentrations of the elements were at their highest at Harjavalta (the most polluted area), apart from Cu which had the highest value at the Cu-treated site at Alkkia. Cu concentrations were above the lowest effective limit (LOEL) on all the plots except for the background plot at Hietajärvi. The maximum Cu values were reached in the topmost 20 cm layer, indicating the effects of mining and smelting activities. The highest Zn and Ni concentrations occurred in the 0–40 cm layer. At all sites, the maximum Pb concentrations were located between 10 and 50 cm. However, the Pb concentrations were higher at Alkkia and Harjavalta than at Outokumpu and Hietajärvi, indicating anthropogenic sources of Pb at the former sites. The As concentration was also the highest in the uppermost peat layers. The mean concentrations were markedly lower in the deeper layers (40–80 cm) than in the upper layers. 相似文献
184.
Phillip F. Steyn BVSc MRCVS MS David Twedt DVM Wanda Toombs CVT 《Veterinary radiology & ultrasound》1995,36(4):327-331
The gastric emptying half-time of solid food in normal cats was determined using a scintigraphic technique. 99m Tc-sulfur colloid was applied to dry food. Sequential images were acquired post prandial, and the gastric emptying half-time was determined for several different acquisition and processing parameters. Good correlation was found between different acquisition and processing methods, some of which made use of edge detection applications, while others used different views, or number of views from which the gastric emptying half-time was calculated. The mean ± standard deviation, (range) and median of the gastric emptying half-time determined using the geometric mean of total counts in hand-drawn regions of interest from the lateral and ventral images were 2.47 × 0.71, (1.42–3.61) and 2.37 hours respectably. 相似文献
185.
186.
宝交早生草莓在0℃下自然降氧贮藏10 d,好果率84%,商品率达98%。用10%CO_2处理可将草莓在0℃的贮藏时间延长到20 d,好果率和商品率均为94%,CO_2浓度超过20%会使草莓产生酒精味。SO_2慢性释放剂处理也有较好的防腐效果。 相似文献
187.
188.
[目的]测定党参中二氧化硫的残留量。[方法]采用比色法快速测定党参中二氧化硫的残留量。[结果]在0.0~48.0μg/ml范围内,二氧化硫浓度与吸光度的线性关系良好,相关系数R为0.999 2,相对标准偏差在0.54%~1.66%;加标回收率为90.1%~103.7%,RSD为1.16%~5.17%(n=6),且具有良好的重现性和稳定性。应用测试结果表明,比色法的测定结果与酸蒸馏法相似。[结论]该方法简便、快速、灵敏度高、干扰少,可用于党参中二氧化硫的残留量测定。 相似文献
189.
构建pcDNA3.1-Foxc2真核表达载体,并以脂质体转染3T3-L1前体脂肪细胞,探究Foxc2对脂代谢的影响。取孕后15d小鼠腹部脂肪组织提取总RNA,用PCR扩增Foxc2全长序列并连接至pMD18-T载体,测序正确后克隆至pcDNA3.1(+)真核表达载体,成功构建pcDNA3.1-Foxc2重组质粒载体。重组质粒转染3T3-L1前体脂肪细胞系,以未转染和空载体转染作为对照,通过RT-PCR和Western blotting法检测Foxc2核酸及蛋白表达,同时检测3T3-L1前体脂肪细胞中脂代谢相关基因FAS、ATGL、HSL及PPARγ的表达。结果显示,重组质粒转染组细胞中Foxc2的核酸和蛋白水平均显著高于对照组。同时发现超表达Foxc2显著降低FAS表达,显著升高HSL及PPARγ的表达,但是对ATGL的表达无显著影响,表明Foxc2具有抑制脂肪沉积的功能。 相似文献
190.
菌株283-1是一株中度嗜盐紫色硫细菌,对其耐盐特性和机理进行了初步研究。结果表明,菌株283-1在改良的Pfennig紫色硫细菌培养基中最大能耐受2.3mol·L-1 NaCl,其生长对Na+有专一依赖性,对Cl-依赖性较弱;它主要通过在胞内积累相容性溶质甜菜碱来对抗胞外渗透压力,胞内甜菜碱的含量随培养基中NaCl浓度增加而增加,2.0mol·L-1 NaCl时浓度可达到156.4mg·g-1干重。外源添加甜菜碱可以明显提高该菌株耐盐生长的能力。 相似文献