硅对水稻生长的影响及其缓解镉毒害机理研究进展

为研发高效硅肥和防治农田镉污染提供借鉴资料,本文综述了施加硅肥对水稻生长发育的影响,包括提高水稻产量和品质,增强抗倒伏、抗病虫害及干旱等逆境的能力,尤其是增强抗镉毒害等能力。并从生理学机制和土壤学机制两方面重点分析了施加硅肥对缓解镉毒害作用的可能机理。生理学机制方面：硅通过参与水稻的生理代谢活动,使水稻抗氧化系统酶的活性和清除自由基的能力增强;抑制镉的吸收及其在水稻体内的运输;硅与镉在水稻体内的螯合和区隔作用。土壤学机制方面：硅肥改变土壤理化性质,降低土壤中有效态镉的含量;硅镉吸附沉淀作用,减少水稻对镉吸收。最后针对硅肥的开发利用及技术推广提出展望。     

Microbial remediation of a pentachloronitrobenzene-contaminated soil under Panax notoginseng: A field experiment

Pentachloronitrobenzene (PCNB) is an organochlorine fungicide that is mainly used in the prevention and control of diseases in crop seedlings. Microbial removal is used as a promising method for in-situ removal of many organic pesticides and pesticide residues. A short-term field experiment (1 year) was conducted to explore the potential role of a PCNB-degrading bacterial isolate, Cupriavidus sp. YNS-85, in the remediation of a PCNB-contaminated soil on which Panax notoginseng was grown. The following three treatments were used:i) control soil amended with wheat bran but without YNS-85, ii) soil with 0.15 kg m^-2 of solid bacterial inoculum (A), and iii) soil with 0.30 kg m^-2 of solid bacterial inoculum (B). The removal of soil PCNB during the microbial remediation was monitored using gas chromatography. Soil catalase and fluorescein diacetate (FDA) esterase activities were determined using spectrophotometry. In addition, cultivable bacteria, fungi, and actinomycetes were counted by plating serial dilutions, and the microbial biodiversity of the soil was analyzed using BIOLOG. After 1 year of in-situ remediation, the soil PCNB concentrations decreased significantly by 50.3% and 74.2% in treatments A and B, respectively, when compared with the uninoculated control. The soil catalase activity decreased in the presence of the bacterial isolate, the FDA esterase activity decreased in treatment A, but increased in treatment B. No significant changes in plant biomass, diversity of the soil microbial community, or physicochemical properties of the soil were observed between the control and inoculated groups (P<0.05). The results indicate that Cupriavidus sp. YNS-85 is a potential candidate for the remediation of PCNB-contaminated soils under P. notoginseng.     

电动技术去除剩余污泥中重金属

电动技术去除污泥中重金属受到多种因素的影响，因此非常有必要探讨适宜的修复参数。本论文系统研究了电解时间、介质pH、强化剂种类、电压和超声振荡时间等因素对电动力学去除剩余污泥中重金属Cu、Zn、Ni、Cr的影响。结果表明，最适宜的电解时间为12 h，最佳介质pH为2，最适电压为1.5 V·cm^-1，最适宜的超声振荡时间为1.0 h。添加EDTA对剩余污泥中Ni的去除效果最佳，最佳添加浓度为0.20 mol·L^-1；添加柠檬酸对剩余污泥中Zn的去除效果最佳，最佳添加浓度为0.25 mol·L^-1；酒石酸对剩余污泥中Cu的去除效果最佳，最佳添加浓度为0.25 mol·L^-1。研究为电动技术去除剩余污泥中重金属的实践提供了理论参考。     

硅对水稻生长的影响及其缓解镉毒害机理研究进展

为研发高效硅肥和防治农田镉污染提供借鉴资料，本文综述了施加硅肥对水稻生长发育的影响，包括提高水稻产量和品质，增强抗倒伏、抗病虫害及干旱等逆境的能力，尤其是增强抗镉毒害等能力。并从生理学机制和土壤学机制两方面重点分析阐述了施加硅肥对缓解镉毒害作用的可能机理。生理学机制方面，硅通过参与水稻的生理代谢活动，使水稻抗氧化系统酶的活性和清除自由基的能力增强;抑制镉的吸收及其在水稻体内的运输;硅与镉在水稻体内的螯合和区隔作用. 土壤学机制方面，硅肥改变土壤理化性质，降低土壤中有效态镉的含量；硅镉吸附沉淀作用，减少水稻对镉吸收。最后针对硅肥的开发利用及技术推广提出展望。     

除草剂莠去津降解菌SFAD3的分离鉴定及其土壤修复潜力

为获得能够修复除草剂莠去津污染土壤的高效降解菌,采用摇瓶富集法、平板分离法从莠去津过量使用的土壤中分离得到降解菌SFAD3,通过形态学、生理生化特征观察以及16S rDNA和ITS序列分析进行种类鉴定,测定获得菌株的最适降解条件,并通过土壤接种和盆栽试验验证菌株对莠去津污染土壤的修复作用。结果表明,菌株SFAD3最终被鉴定为门多萨假单胞菌Pseudomonas mendocina,该菌株培养30 d时对污染土壤中50 mg/kg莠去津的降解率可达72.6%;菌株SFAD3在MM液体培养基中最适降解条件为温度37℃、pH 7、莠去津初始浓度6.25 mg/L、接种量2%,对莠去津降的降解率为50.0%～72.2%;与仅有莠去津的处理相比,添加有SFAD3发酵液的处理20 d后芝麻的株高、根长、湿重和干重能够显著恢复,并且该菌对芝麻还具有一定的促生作用。表明降解菌SFAD3在修复莠去津污染土壤方面具有潜在的应用价值。     

A preliminary trial of the sedation induced by intranasal administration of midazolam alone or in combination with dexmedetomidine and reversal by atipamezole for a short‐term immobilization in pigeons

ObjectiveTo assess the sedative and immobilization effect of intranasal administration (INS) of midazolam (MID) without or with INS dexmedetomidine (DXM), and some physiological changes induced by the drugs. The ability of INS atipamezole to reverse the DXM component was also assessed.Study designProspective ‘blinded’ experimental study.AnimalsIn total, 15 pigeons.MethodsPigeons were sedated by INS MID alone at a dose of 5 mg kg⁻¹ (group MID, n = 6) or in combination with INS DXM at a dose 80 μg kg⁻¹ (group MID-DXM, n = 6). Measurements were made of heart rate (HR), respiratory rate (f_R) and cloacal temperature (CT). The degree of sedation was assessed at 15 minutes prior to, immediately after, and at intervals until 100 minutes after drug administrations. Following MID-DXM, INS atipamezole (250 μg kg⁻¹) was administered and the same indices measured 5 and 10 minutes later.ResultsMID had no effect on HR and f_R, and although CT decreased, it remained within physiological range. MID-DXM caused significant falls in HR, f_R and CT that persisted until the end of sedation. Atipamezole antagonized sedation and cardiorespiratory side effects of MID-DXM within 10 minutes of application. In addition, for MID compared to MID-DXM, the lowest sedation scores [10 (7–14) and 10.5 (5–14) versus 2 (1–4) and 2 (1–5)] were achieved in the 10th and 20th minute versus the 20th and 30th minute of the sedation, respectively.Conclusions and clinical relevanceMID alone, given INS had minimal side effects on vital functions but caused inadequate immobilization of pigeons for restraint in dorsal recumbency. MID-DXM caused an effective degree of immobilization from 20 to 30 minutes after administration, at which time birds tolerated postural changes without resistance. Atipamezole antagonized both side effects and sedation, but complete recovery had not occurred within 10 minutes after its application.     

Accelerated induction of etorphine immobilization in blue wildebeest (Connochaetes taurinus) through the addition of hyaluronidase

ObjectiveTo study the effects of the addition of hyaluronidase (HA) to an etorphine/azaperone drug combination on induction times of immobilization.Study designExperimental part-randomized ‘blinded’ cross-over study.AnimalsEight wild managed blue wildebeest (Connochaetes taurinus).MethodsAnimals were immobilized, on separate occasions separated by two weeks, with one of four treatments. Treatments were; ‘Control drugs (CD), etorphine 0.01 mg kg⁻¹ + azaperone at 0.1 mg kg⁻¹; treatment 1 CD + 5000IU HA; treatment 2 CD + 7500 IU HA; and treatment 3 etorphine 0.007 mg kg⁻¹ + azaperone at 0.07 mg kg⁻¹ + 7500 IU HA. Times to first effect and to immobilization (from darting to possible to approach and blindfold) were measured. anova was used to compare treatments. Results are given in means ± SD (range).ResultsFor control, and treatments 1–3 respectively, times (in minutes) to first effect were 1.58 ± 0.42 (1.02–2.10), 1.64 ± 0.42 (0.95–2.17), 1.12 ± 0.24 (0.80–1.48) and 1.60 ± 0.21 (1.13–1.88) and to immobilization were 5.38 ± 1.53 (3.82–8.07), 3.80 ± 1.14 (2.02–5.50), 3.51 ± 1.08 (2.28–5.52) and 4.46 ± 0.67 (3.30–5.40). Compared to control, time to first effect for treatment 2 was significantly shorter. Time to immobilization was significantly quicker in all three treatments containing HA than that for control.Conclusion and clinical relevanceHyaluronidase can reduce the time to immobilization when used in the immobilizing dart, and might be usefully incorporated into etorphine combinations for darting wildlife.     

Studies on Heavy Metal Pollution in Soil—Plant System：A Review

Heavy metal pollution in soil-plant system is of major environmental concern on a world scale and in China in particular with the rapid development of industry.The heavy metal pollution status in soil-plant system in China,the research progress on the bioavailability of heavy metals (effecting factors,extraction methods,free-ion activity model,adsorption model,multivariate regression model,Q-I relationship,and compound pollution),and soil remediation are reviewed in paper.Future research and monitoring is also discussed.     

Does Biochar Improve Establishment of Tree Seedlings in Saline Sodic Soils?

Reforestation of saline sodic soil is increasingly undertaken as a means of reclaiming otherwise unproductive agricultural land. Currently, restoration of degraded land is limited to species with high tolerances of salinity. Biochar application has the potential to improve physical, biological and chemical properties of these soils to allow establishment of a wider range of plants. In a glasshouse trial, we applied biochar made from Acacia pycnantha (5 Mg ha⁻¹) or no biochar to either a low (EC_e 4·75 dS m⁻¹, ESP 6·9), a moderate (EC_e 27·6 dS m⁻¹, ESP 29·3) or a high (EC_e 49·4 dS m⁻¹, ESP 45·1) saline sodic soil. The regional common reforestation species Eucalyptus viminalis and Acacia mearnsii were planted as tubestock in to the soils. Early establishment indicators, including growth, plant condition and nutrition, were assessed at the end of a simulated growing season, 108 days after biochar application. Application of biochar increased height, and decreased root : shoot and the concentration of Mn, N and S in plants of E. viminalis when grown in the highly saline sodic soil. Biochar application increased the concentration of B in leaves of E. viminalis and increased the concentration of P, K and S in leaves of A. mearnsii when grown in the low saline sodic soil. The results confirm that there is potential for biochar to assist in reforestation of saline sodic soils. Copyright © 2015 John Wiley & Sons, Ltd.