Cu2+对中华倒刺鲃超氧化物歧化酶活性的影响     

孙翰昌  丁诗华  代梅  黄丽英  耿晓修 《西南大学学报(自然科学版)》2005,27(5):709-712

Cu2+是养殖水体的常见污染物,为了评估Cu2+对鱼类超氧化物歧化酶(SOD)的影响,将中华倒刺鲃暴露于含0.01～0.32 mg/L Cu2+的水体中饲养8 d,测定肌肉、血浆及肝脏中SOD活性的变化.实验结果显示,低浓度Cu2+(0.01 mg/L)对肌肉、血浆及肝脏的SOD有诱导作用,随着处理时间的延长而升高.但当浓度较高(0.04mg/L以上)时,SOD活性均呈现先诱导后抑制的趋势.Cu2+浓度越高,SOD活性上升越急剧,出现活性抑制的时间就越提前.此外,SOD在3种组织中的分布亦存在明显差异,肝脏的SOD活性最大.这些结果表明,肝脏SOD活性更宜作为Cu2+污染的生物标记.  相似文献   

Evidence from Opportunity's Microscopic Imager for water on Meridiani Planum     

Herkenhoff KE  Squyres SW  Arvidson R  Bass DS  Bell JF  Bertelsen P  Ehlmann BL  Farrand W  Gaddis L  Greeley R  Grotzinger J  Hayes AG  Hviid SF  Johnson JR  Jolliff B  Kinch KM  Knoll AH  Madsen MB  Maki JN  McLennan SM  McSween HY  Ming DW  Rice JW  Richter L  Sims M  Smith PH  Soderblom LA  Spanovich N  Sullivan R  Thompson S  Wdowiak T  Weitz C  Whelley P 《Science (New York, N.Y.)》2004,306(5702):1727-1730

The Microscopic Imager on the Opportunity rover analyzed textures of soils and rocks at Meridiani Planum at a scale of 31 micrometers per pixel. The uppermost millimeter of some soils is weakly cemented, whereas other soils show little evidence of cohesion. Rock outcrops are laminated on a millimeter scale; image mosaics of cross-stratification suggest that some sediments were deposited by flowing water. Vugs in some outcrop faces are probably molds formed by dissolution of relatively soluble minerals during diagenesis. Microscopic images support the hypothesis that hematite-rich spherules observed in outcrops and soils also formed diagenetically as concretions.  相似文献   

Energy balance for ethyl alcohol production from crops     

DA Silva JG  Serra GE  Moreira JR  Conçalves JC  Goldemberg J 《Science (New York, N.Y.)》1978,201(4359):903-906

Energy requirements to produce ethyl alcohol from three different crops in Brazil (sugarcane, cassava, and sweet sorghum) were calculated. Figures are presented for the agricultural and industrial phases. The industrial phase is always more energy-intensive, consuming from 60 to 75 percent of the total energy. Sugarcane is the more efficient crop for ethyl alcohol production, followed by sweet sorghum and cassava from a net energy viewpoint. The utilization of sweet sorghum stems might increase the total energy gain from this crop to almost the same level as sugarcane. Cassava has a lower energy gain at the present state of agriculture in Brazil.  相似文献   

植物生长素在大果沙棘嫩枝扦插中的应用研究   总被引：2，自引：0，他引：2  

达哇卓玛 《青海农林科技》2007,(1):7-8,16

在温室内对5个大果沙棘品种嫩枝用4种植物生长激素处理进行扦插育苗试验,结果表明,吲哚丁酸和生根粉处理效果显著,浑金和向阳两品种更容易扦插成活。  相似文献   

Impact of heavy metal amended sewage sludge on forest soils as assessed by bacterial and fungal biosensors     

Jacqui Horswell  Hedda J. Weitz  Harry J. Percival  Tom W. Speir 《Biology and Fertility of Soils》2006,42(6):569-576

Bacterial and fungal bioluminescence-based biosensors were used as indicators of potential heavy metal toxicity to microorganisms in the needle litter of a mature Pinus radiata forest under heavy metal contaminated sewage sludge. Sewage sludge was amended with increasing concentrations of Cu, Ni and Zn and applied to the surface of a mature P. radiata forest. The response of the bacterial and fungal biosensors to soluble Cu, Ni and Zn in needle litter extracts was investigated. The bioluminescence response of the bacterial biosensor Escherichia coli HB101 pUCD607 declined as water-soluble Zn concentrations increased. The effective concentrations that gave a 50% reduction in bioluminescence (EC₅₀ values) for water-soluble Zn and total litter Zn were 1.3 mg l⁻¹ and 3700 mg kg⁻¹, respectively. The bioluminescence response of the fungal biosensor Armillaria mellea declined as soluble Cu concentrations increased. The EC₅₀ values for water-soluble Cu and total litter Cu were 0.12 mg l⁻¹ and 540 mg kg⁻¹, respectively. No decline in bioluminescence was noted for either the bacterial or fungal biosensor on exposure to increasing concentrations of water-soluble Ni. The use of a combination of bacterial and fungal biosensors offers a rapid and sensitive tool for assessing toxicity of heavy metals to microorganisms and, thus, elucidating the environmental impact of contaminants in sewage sludge on litter dwelling microorganisms.  相似文献   

Coelioscopic-assisted prefemoral ovariosalpingectomy in a d`Orbigny slider (Trachemys dorbigni) using a digital otoscope     

Bernardo Nascimento ANTUNES  Diego DA COSTA  Michelli Westphal DE ATAIDE  Allana Valau MOREIRA  Luis Fernando PEDROTTI  Francisco Schulz JÚNIOR  Cassiano Schmitz NHOATO  Renan Alves STADLER  Marco Augusto Machado SILVA  Maurício Veloso BRUN 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2020,82(12):1802

The purpose of this study was to assess the unilateral prefemoral coelioscopic-assisted approach for ovariosalpingectomy in a d`Orbigny slider (Trachemys dorbigni) using a digital otoscope. Twenty healthy turtles were randomly assigned to one of two groups, for right (GR; n=10) or left (GL; n=10) prefemoral access, for coelioscopic-assisted ovariosalpingectomy. Anesthesia and surgery times, body weight, and ovary/oviduct weight data were recorded. Anesthesia and surgery times did not differ significantly between the groups. Wound closure was the most time-consuming surgical step. Ovary and body weights significantly affected the exposure time of the ipsilateral and contralateral ovaries, respectively. Two intraoperative complications were reported. All the animals recovered uneventfully. The digital otoscope can be safely and effectively used for coelioscopic-assisted single-access, unilateral prefemoral ovariosalpingectomy in d`Orbigny slider.  相似文献   

黍族植物的叶片扩张和蒸腾作用对土壤水分亏缺的响应特征     

M. ESMAEILZADE-MORIDANI  B. KAMKAR  S. GALESHI  F. GHADERIFAR  J. A. TEIXEIRA DA SILVA 《土壤圈》2015,25(6):834-843

Plant processes, such as leaf expansion, stomatal conductance and transpiration, are affected by soil water, particularly in water-stressed environments. Quantifying the effects of soil water on plant processes, especially leaf expansion and transpiration, could be useful for crop modeling. In order to quantify the leaf expansion and transpiration in response to soil water deficit in three millet species, common (Panicum miliaceum L.), pearl (Pennisetum glaucum L.) and foxtail (Setaria italica L.) millets, a pot experiment was performed at the Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. The soil water status was characterized by the fraction of transpirable soil water (FTSW). Leaf area and transpiration were measured daily. Relative leaf area expansion (RL) and relative transpiration (RT) data were plotted against FTSW. Finally the FTSW thresholds for RL and RT were calculated using linear-plateau and logistic models. The results showed that the thresholds for RL and RT were 0.68 and 0.62, respectively, based on all measured data of the three millet species using the linear-plateau model, indicating that RL and RT were constant when FTSW decreased from 1 to the threshold point. Thereafter, until FTSW = 0, RL and RT declined linearly with a slope of 1.48 and 1.43, respectively. Although millet is cultivated as a resistant crop in arid, semiarid and marginal lands, it showed an early response to soil water deficit at high FTSW thresholds. As leaf expansion and transpiration can be considered morphological and physiological variables, respectively, the results in this study indicate that millet has strong morphological flexibility when faced with soil water deficit.  相似文献   

西藏核桃休眠及萌芽特性研究   总被引：1，自引：0，他引：1  

曲芬霞  姚霞珍  郭建斌  李文博  达瓦次仁  索朗桑姆 《种子》2011,30(3)

利用浓硫酸浸泡处理西藏核桃种子,通过种子吸水率、不同层积方法和内源抑制物对小白菜萌发影响试验等方面来研究西藏核桃的休眠及萌芽特性.结果表明:用浓硫酸处理种吸水率大于对照,种壳并不是引起休眠的主要原因,外壳、内种皮、种仁可能均含有抑制种子发芽物质.用浓硫酸浸泡90 min,变温层积萌动时间早,且萌动率高;低温层积160 d,再在22℃恒温条件下发芽率高,为68%.  相似文献   

森林公园道路景观林的改造配置模式——以老山森林公园为例     

笪红卫  康宏兴  邵娟  何伟 《江西林业科技》2011,(6):61-63

道路景观林是山林景观的窗口和向导,道路景观林的建设是森林林相改造的重要内容。以南京市老山森林公园为例,探讨道路景观林建设的指导思想、原则与方法,并结合案例提出道路景观林改造模式,以实现森林公园由经济林转变为景观生态林的改造目标。  相似文献   

Alkaline hydrolyzable nitrogen and properties that dictate its distribution in paddy soil profiles     

Gerson Laerson DRESCHER  Leandro Souza DA SILVA  Qamar SARFARAZ  Gustavo DAL MOLIN  Laura Brondani MARZARI  Augusto Ferreira LOPES  Cesar CELLA  Daniela Basso FACCO  Rodrigo Knevitz HAMMERSCHMITT 《土壤圈》2020,30(3):326-335

Nitrogen (N) is a key nutrient for rice production, and its bioavailability in paddy soils is strongly coupled to soil organic matter (SOM) cycling. A better understanding of potentially available N forms in soil, such as alkaline hydrolyzable N (AH-N), and their depth distribution will support the development of best management practices to improve the N use efficiency of rice while minimizing adverse environmental effects. Fifteen rice (Oryza sativa L.) fields from Southern Brazil were selected, and stratified soil samples were taken to a depth of 60 cm before crop establishment. Selected soil physical and chemical properties were analyzed to evaluate their relationships with AH-N contents in the soil profile. The AH-N contents below 20 cm varied extensively (increased, reduced, or constant) compared with that above 20 cm. Although clay and clay + silt contents were highly correlated to AH-N for some soils, the major property dictating AH-N distribution by depth was total N (TN), as the correlation between TN and AH-N was mainly by direct effect. The proportion of TN recovered as AH-N across sites and depths presented high amplitude, and thus AH-N was not a constant N pool across depths, indicating that AH-N can be affected by soil management practices even when TN showed no major changes. The distinct distribution of AH-N across soil sampling sites and depths indicates that depths greater than 20 cm should be considered when calibrating the AH-N index for N fertilizer recommendations for flooded rice in Southern Brazil.  相似文献