高浓度城市污水处理正交试验研究

针对新疆石河子市城市污水CODcr高于1000mg／L的特点，采用SBR工艺进行处理试验，并用正交试验的方法对最佳工艺条件进行了探讨。试验表明，该工艺对高浓度城市污水有较好的处理效果。通过控制运行条件，可使出水各项指标分别满足污水综合排放标准和农业灌溉的要求。     

基于计算机视觉系统的溶液浓度快速检测方法

基于计算机视觉系统的RGB色度学理论,提出一种测定有色溶液浓度的数字色度法,并开发了与之配套的软件检测系统。该方法与分光光度计相比,大大提高了检测效率,理论上每分钟可完成上百个样品浓度的同时测定。通过软件系统分析样品色度信息,实现自动显示被测溶液浓度的良好效果,为一次性成批检测溶液浓度提供了一种简捷快速的新思路。     

高浓度细胞分裂素诱导棉花悬浮细胞程序性死亡

棉花悬浮细胞经高浓度细胞分裂素（2mg／L KT或4mg／L KT）处理后第4天大量死亡，培养物呈褐黑色；抽提总DNA，进行琼脂糖胶电泳，结果表明：2mg／L KT和4mg／L KT两处理中有明显的大小为140～180bp及其倍增量片段的DNA“梯”。进行PI和FDA染色显微观察可以看到：2mg／L KT处理中大部分细胞的细胞核较小，核质浓缩，呈棒形或弯月形；胞质浓缩，出现了不对称的质壁分离，且丧失了FDA染色活性。这些结果表明，由高浓度细胞分裂素处理引起的棉花悬浮细胞大规模死亡是一种细胞程序性死亡（PCD）。不同的生理状态（UCSA和BAE）和不同生长时期（指数增长期和静止期）的棉花悬浮细胞对高浓度细胞分裂素的诱导反应存在差异。     

不同剂量药剂防治山楂梨小食心虫的综合效益评价

为有效防治山楂梨小食心虫,选用20%氰戊马拉松乳油(A1)、20%毒死蜱微囊悬浮剂(A2)和10%阿维除虫脲乳油(A3)3种有代表性的农药,分别配以3种剂量即400倍液(B1)、800倍液(B2)和1 200倍液(B3),进行药剂喷施试验,以清水处理(B4)为对照,以好果率、好果产量、收入和净增纯收益4个农艺、经济指标为评价因素,对药剂防治综合经济效益进行同异分析。方差分析结果表明,3种药剂中,A2、A3防治效果(好果率)均较好,分别达到89.99%和89.94%;3种剂量之间无显著差异,防治效果在92.50%~95.83%。对好果率、好果产量、收入和净增纯收益4个因素的同异分析结果表明,A2B1综合效果最好,达到优良水平,其后依次为A2B2、A3B2、A3B3、A2B3、A3B1和A1B1,达到较好水平,以上7个处理的净增纯收益在8 626.5~13 615.5元/hm2。     

Phosphorus Response and Fertilizer Recommendations for Wheat Grown on Nitisols in the Central Ethiopian Highlands

The provision of farmers with proper and balanced fertilizer recommendations is becoming increasingly important, for reasons of crop productivity, food security, and sustainability. Phosphorus (P) response trials with wheat were conducted on Nitisols at 14 sites in the central Ethiopian highlands during the 2010 and 2011 cropping seasons. The treatments, comprising six levels of P fertilizer (0, 10, 20, 30, 40, and 50 kg P ha^?1), were arranged in a randomized complete block design with three replicates. Based on a yield difference between the control and the P treatments, 90% of sites responded to P fertilizer. Application of P fertilizer increased wheat grain yield, up to 30% more than the control. Extractable soil P concentrations (Bray 2, 0–15 cm deep) 3 weeks after planting significantly responded to P fertilizer rate. The critical P concentration (for 90% relative yield) was 13.5 mg kg^?1. Most sites tested had Bray 2 P values <10 mg kg^?1. In the absence of a soil test, a recommendation of 40 kg P ha^?1, resulting in the best response overall, could be made for the first year of application. We also recommend that to prevent a potential loss of wheat yield, a maintenance application of at least 5–12 kg P ha^?1 be applied every year, irrespective of the calculated recommended rate, in order to replace P exported from the field in produce. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices.     

Excess trace metal effects on cotton: 4. Chromium and lithium in Yolo loam soil

Abstract

Two cultivars of cotton (Gossypium spp) were grown in Yolo loam soil in a glasshouse to determine phytotoxicity effects of Cr and Li and possible interactions with other metals. The Cr at 100 μg/g soil had no adverse effects on either cultivar studied. A Cr increase was not observed in either stems or leaves. Both cultivars tolerated 25 and 50 μg Li/g soil. The 50 μg Li/g soil resulted in leaves of Acala SJ‐2 with 432 μg Li/g leaves and 720 in Giza 45. The 100 μg Li/g soil resulted in 74% and 87% leaf yield reductions in Acala SJ‐2 and Giza 45 respectively. Leaf concentrations of Li respectively were 1950 and 1850 μg/g. Except at the highest level of Li, leaves had higher concentrations of Li than did roots. The Cr and Li resulted in some plant metal interactions.     

Correlation of Soil pH and Mehlich‐3 Phosphorus with Postflood Rice Phosphorus Concentrations in Arkansas

Abstract

Plant‐available phosphorus (P) measured by routine soil‐test methods is poorly correlated with rice grain yield in Arkansas. Our objective was to determine whether soil water pH (pH_w) and Mehlich‐3 P were correlated with growth and yield of rice grown on silt loam soils. Data from 35 field studies were used to correlate Mehlich‐3 P and pH_w with relative yield, dry matter accumulation, and P concentration at the midtillering stage. Significant linear or nonlinear relationships between pH_w or Mehlich‐3 P with rice growth parameters were delineated but explained less than 27% of the variability in dry matter and P concentrations at the midtillering stage and grain yield at maturity. Mehlich‐3 P and pH_w together explained 61% of the variability in midtillering P concentrations. Midtillering whole‐plant P concentrations were positively related to relative grain yield and dry matter production and will be used to identify soils with limited P availability for rice in Arkansas.     

产单核细胞李斯特菌P60蛋白的可溶性表达

以食品中分离到的L.mXFL0605株为试验菌株,PCR扩增得到iap全基因。将iap连接到pET-28a(+)载体进行原核表达,分别采用培养温度为25℃或37℃,IPTG浓度为5μg/mL或10μg/mL优化组合进行诱导。结果显示,当采用37℃培养和10μg/mLIPTG诱导时可以获得部分可溶性表达的p60,重组p60蛋白分子质量约60 ku。     

Effects of stocking density and algal concentration on the survival,growth and metamorphosis of Bobu Ivory shell,Babylonia formosae habei (Neogastropoda: Buccinidae) larvae

Independent and combined effects of stocking density and algal concentration on the survival, growth and metamorphosis of the Bobu Ivory shell Babylonia formosae habei larvae were assessed using a 5 × 5 factorial design with densities of 0.25, 0.5, 0.75, 1.00 and 1.50 larvae mL⁻¹ and algal concentrations of 5, 10, 15, 20 and 25 × 10⁴ cells mL⁻¹ in the laboratory. Larval growth, survival and metamorphosis were significantly affected by both the independent effects of stocking density and algal concentration and by their interaction. The highest per cent survival (72.5%) and metamorphosis (49.5%), fastest growth (41.57 μm day⁻¹) and shortest time to initial metamorphosis (10 days) all occurred at the lowest stocking density and the highest algal concentration. Both crowding and food limitation had independently negative impacts on the survival, growth and metamorphosis of larvae, and these negative impacts were further strengthened by the interaction of a higher stocking density and a lower algal concentration. Moreover, the results suggest that stocking density and algal concentration obviously played different roles in determining larval survival and growth. To maximize survival and growth, B. formosae habei larvae should be reared at a lower stoking density of 0.25 larvae mL⁻¹ and fed a higher algal concentration of 25 × 10⁴ cells mL⁻¹ in large-scale hatchery seed culture.