Combined effects of elevated temperature and CO2 concentration on Cd and Zn accumulation dynamics in Triticum aestivum L.

A simulated climate warming experiment was conducted to evaluate the combined effects of elevated temperature and CO_2 concentration on the bioaccumulation,translocation and subcellular distributions of Cd and Zn in wheat seedlings(Triticum aestivum L.cv.Xihan 1.) at Dingxi,Gansu Province,China.The objective was to find evidence that global climate change is affecting the bioaccumulation of Cd and Zn in T.aestivum L.cv.Xihan 1.The results showed that compared to control A,elevated temperature and CO_2 increased Cd bioaccumulation in the shoots by 1.4–2.5 times,and increased that in the roots by 1.2–1.5times,but decreased Zn levels in wheat shoots by 1.4–2.0 times,while decreased that in the roots by 1.6–1.9 times.Moreover,temperature and CO_2 concentration increase also led to increased Cd concentration,and decreased Zn concentration in subcellular compartments of wheat seedlings.The largest Cd concentration increase(174.4%) was observed in the cell wall and debris fractions of shoots after they were subjected to the highest CO_2 and temperature treatment(TC3).The largest Zn concentration decrease(53.1%) was observed in the soluble(F3) fractions of shoots after they were subjected to the medium CO_2 and temperature treatment(TC2).The temperature and CO_2 increase had no significant effect on the proportional distribution of Cd and Zn in the subcellular fractions.The root-to-shoot translocation of Cd increased with the increasing temperature and CO_2 concentration.However,the Zn distributions only fluctuated within a small range.     

Transient‐phase and steady‐state kinetics of lipase‐catalyzed ester hydrolysis 1

Abstract

An experimental study has been made of both the steady‐state and the transient‐phase (presteady‐state) kinetics of the hydrolyses of several saturated aliphatic esters of p‐nitrophenol catalyzed by wheat germ lipase. The analysis of the presteady‐state part revealed two transients indicating that lipase‐catalyzed reactions proceed via a two‐intermediate mechanism suggested for other esterases. The possibility of more than one species of the enzyme engaged in catalytic activity is discussed and a reaction mechanism scheme is proposed accordingly.     

Secondary organic aerosol formation from straw burning using an oxidation flow reactor

Herein, we use an oxidation flow reactor, Gothenburg: Potential Aerosol Mass (Go: PAM) reactor, to investigate the secondary organic aerosol (SOA) formation from wheat straw burning. Biomass burning emissions are exposed to high concentrations of hydroxyl radicals (OH) to simulate processes equivalent to atmospheric oxidation of 0-2.55 days. Primary volatile organic compounds (VOCs) were investigated, and particles were measured before and after the Go: PAM reactor. The influence of water content (i.e. 5% and 11%) in wheat straw was also explored. Two burning stages, the flaming stage, and non-flaming stages, were identified. Primary particle emission factors (EFs) at a water content of 11% (∼3.89 g/kg-fuel) are significantly higher than those at a water content of 5% (∼2.26 g/kg-fuel) during the flaming stage. However, the water content showed no significant influence at the non-flaming stage. EFs of aromatics at a non-flaming stage (321.8±46.2 mg/kg-fuel) are larger than that at a flaming stage (130.9±37.1 mg/kg-fuel). The OA enhancement ratios increased with the increase in OH exposure at first and decreased with the additional increment of OH exposure. The maximum OA enhancement ratio is ∼12 during the non-flaming stages, which is much higher than ∼ 1.7 during the flaming stages. The mass spectrum of the primary wheat burning organic aerosols closely resembles that of resolved biomass burning organic aerosols (BBOA) based on measurements in ambient air. Our results show that large gap (∼60%-90%) still remains to estimate biomass burning SOA if only the oxidation of VOCs were included.     

某火力发电厂周围小麦受SO2污染调查

对某火力发电厂排放SO2导致其周围小麦受污染的突发性事故进行了调查。通过实地勘察小麦的受害症状，发现小麦呈典型的硫氧化物危害和硫酸雾腐蚀特征；小麦生物学性状和产量调查结果表明，污染区与对照区小麦无论株高、茎粗、穗长均无显著差异。而小麦的产量已受到影响，与对照区相比差异极显著；污染区小麦叶片全硫量和水溶性硫测定结果表明，全硫量均值为0．759％，高出对照区全硫含量均值0．651％的17％，经t检验差异显著；水溶性硫含量均值0．64％，高出对照区水溶性硫含量均值0．52％的23％，经检验差异极显著，表明污染区小麦受害确系SO2所致；分析气象条件认为污染区小麦是在低气压、高湿度、低风速、偏西风和稳定天气频率偏高的状况下受到污染的。     

Arsenic adsorption on lignocellulosic substrate loaded with ferric ion

We loaded a lignocellulosic substrate extracted from wheat bran with ferric ions. This new low-cost adsorbent was prepared for the adsorption and removal of arsenate and arsenite ions from aqueous systems. The loading process of Fe in this biomaterial was done by hydrolization of a ferric salt while an alkaline solution was added dropwise. The new material obtained has a high sensivity to arsenite and arsenate species. Here, we investigated the effect of contact time, pH, and Fe content on the adsorption of both arsenic ions on the new material. This adsorption was found to be highly pH-dependent, which can be explained on the basis of electrostatic interactions between ionic species in solution and the ≡FeOH surface groups. The maximum adsorption capacity of arsenite and arsenate species vary linearly with the amount of Fe loaded on the lignocellulosic substrate.     

用基因枪介导法将水稻几丁质酶基因导入小麦

利用PDS1000／氦气基因枪将水稻几丁质酶基因导入小麦幼胚盾片愈伤组织．基因枪轰击后在含有50mg／L硫酸卡那霉素的培养基上经过多步骤筛选和分化，从5个小麦品种共800多个幼胚中获得了6株绿苗，对此6株绿苗进行了PCR和Southern杂交分析．结果表明，其中4株绿苗为转基因植株，转化率最高可达1．2％．图3表2参17     

黄河三角洲土壤(潮土)石油类含量对小麦的影响研究

本文在分析黄河三角洲土壤石油类含量状况、通过盆栽试验研究小麦对当地土壤 (潮土 )石油类含量耐受度的基础上 ,建立物流模型 ,得出了在不受污油、落地油污染的地方土壤 (潮土 )石油类含量对小麦的不利影响在较长时间内将是微弱的基本结论。     

微波辐照麦秸制造活性炭

研究了微波辐照经氯化锌浸渍的麦秸制造活性炭。实验结果表明,经微波辐照８ｍｉｎ,所得到活性炭的亚甲蓝脱色力为１７０ｍＬ／ｇ,为国家标准一级品（ＬＹ２１６－７９）的１．４２倍,时间仅为传统方法的１／４５。     

重庆市巴县,长寿县水稻和小麦的重金属污染

重庆市巴县和长寿县的部分水稻和小麦已经受到重金属汞、镉、铅的污染，污染程度长寿县〉巴县，小麦〉水稻，铅〉汞〉镉。污染的主要原因是环境污染所造砀 ，尤其是重化工业所在场镇附近污染特别显著，汞和铅污染有加重趋势，镉污染有所减轻，提出了对策建议。     

Effect of fertilization and irrigation schedule on water and fertilizer solute transport for wheat crop in a sub-humid sub-tropical region

In order to increase the water and fertilizer use efficiency and decrease the losses of water and fertilizer solutes (N and P), it is necessary to assess the influence of level of fertilization and irrigation schedule on movement and balance of water and fertilizers in the root zone. With this goal, the reported study was undertaken to determine the effect of fertilization and irrigation schedule on water movement and fertilizer solute transport in wheat crop field in a sub-tropical sub-humid region. Field experiments were conducted on wheat crop of cultivar Sonalika (Triticum aestivum L.) during the years 2002–2003, 2003–2004 and 2004–2005. Each experiment consisted of four fertilizer treatments and three irrigation treatments during the wheat growth period. During the experiment, the irrigation treatments were: I₁ = 10% maximum allowable depletion (MAD) of available soil water (ASW); I₂ = 40% MAD of ASW; I₃ = 60% MAD of ASW. The fertilizer treatments during the experiment were: F₁ = control treatment with N:P₂O₅:K₂O as 0:0:0 kg ha⁻¹; F₂ = fertilizer application of N:P₂O₅:K₂O as 80:40:40 kg ha⁻¹; F₃ = fertilizer application of N:P₂O₅:K₂O as 120:60:60 kg ha⁻¹ and F₄ = fertilizer application of N:P₂O₅:K₂O as 160:80:80 kg ha⁻¹. The results of the investigation revealed that low volume high frequency irrigation results in higher deep percolation losses than the low frequency high volume irrigation with different levels of fertilization for wheat crop in coarse lateritic soil, whereas different levels of fertilization did not significantly affect soil water balance of the wheat crop root zone during all the irrigation schedules. Level of fertilization and irrigation schedule had significant effect on nitrogen leaching loss whereas irrigation schedules had no significant effect on nitrogen uptake under different levels of fertilization. On the other hand, the leaching loss of phosphorus was not significantly influenced by the irrigation schedule and level of fertilization of wheat crop. This indicated that PO₄–P leaching loss was very low in the soil solution as compared to nitrogen due to fixation of phosphorus in soils. From the observed data of nitrogen and phosphorus use efficiency, it was revealed that irrigation schedule with 40% maximum allowable depletion of available soil water with F₂ fertilizer treatment (N:P₂O₅:K₂O as 80:40:40 kg ha⁻¹) was the threshold limit for wheat crop with respect to nitrogen and phosphorus use, crop yield and environmental pollution.