Tractive power in organic farming based on fuel cell technology – Energy balance and environmental load

This study analysed a future hypothetical organic farm self-sufficient in renewable tractor fuel. Biomass from the farm was assumed to be transported to a central fuel production plant and the fuel returned to the farm, where it was utilised in fuel cell powered tractors. The land use, energy balance and environmental impact of five different scenarios were studied. In the first two scenarios, straw was used as raw material for production of hydrogen or methanol via thermochemical gasification. In the third and fourth scenarios, short rotation forest (Salix) was used as raw material for the same fuels. In the fifth scenario, ley was used as raw material for hydrogen fuel via biogas production.The straw scenarios had the lowest impact in all studied environmental impact categories since the Salix scenarios had higher soil emissions and the ley scenario had comparatively large emissions from the fuel production. The energy balance was also favourable for straw, 16.3 and 19.5 for hydrogen and methanol respectively, compared to Salix 14.2 and 15.6. For ley to hydrogen the energy balance was only 6.1 due to low efficiency in the fuel production.In the Salix scenarios, 1.6% and 2.0% of the land was set aside for raw material production in the hydrogen and methanol scenarios respectively. In the straw scenarios no land needed to be reserved, but straw was collected on 4.3% and 5.3% of the area for hydrogen and methanol respectively. To produce hydrogen from ley, 4% of the land was harvested.The study showed that the difference in environmental performance lay in choice of raw material rather than choice of fuel. Hydrogen is a gas with low volumetric energy density, which requires an adapted infrastructure and tractors equipped with gas tanks. This leads to the conclusion that methanol probably will be the preferred choice if a fuel cell powered farm would be put into practice in the future.     

Control of lemon postharvest diseases by low-toxicity salts combined with hydrogen peroxide and heat

The effectiveness of potassium sorbate, sodium bicarbonate and potassium phosphite combined with heat and hydrogen peroxide in the presence of CuSO₄ to control major lemon postharvest diseases was investigated on artificially infected fruit. Green and blue molds, which both require wounds for infections to occur, were controlled by combination of hydrogen peroxide followed by inorganic salts, even when the temperature solutions were 25 °C. Control of sour rot was poor with salt solutions alone but significantly improved in treatments including hydrogen peroxide followed by potassium sorbate or sodium bicarbonate at 50 °C. Phomopsis stem-end rot was effectively controlled by potassium sorbate and potassium phosphite at 20 °C, and diplodia stem-end rot was partially controlled only by potassium sorbate. Applications of either potassium sorbate or a sequence of hydrogen peroxide followed by potassium phosphite were the most promising treatments, primarily because they controlled most of the diseases without the need to heat the solutions. These treatments controlled postharvest citrus diseases to useful levels and could be suitable alternative to conventional fungicides, or could be applied with them to improve their performance or to manage fungicide resistant isolates.     

化学杀雄剂EXP对油菜膜脂过氧化及保护酶活性的影响(英文)

[Objective] The aim of this study was to investigate the characteristics and mechanism of chemical emasculation in rapeseed and to provide the theoretical basis for development and utilization of new chemical gametocides.[Method] The activity of peroxidase,catalase and the content of hydrogen peroxide,malondialdehyde in leaves and flower buds of Brassica napus cultivars Qinyou No.3 and L89 induced by the chemical gametocide EXP in the course of male sterility were studied.[Result] Protective enzyme activity and the content of hydrogen peroxide,malondialdehyde in rapeseed treated with EXP changed significantly,which indicated that active oxygen metabolism was abnormal.Furthermore,there was a significant difference in the reaction degree of different cultivars and organs treated by EXP.[Conclusion] There was a correlation between the disturbance of active oxygen metabolism and the male sterility induced by chemical gametocide EXP.     

外源过氧化氢对NaCl胁迫下玉米种子萌发和幼苗抗氧化酶活性的影响

为了阐明外源过氧化氢(H₂O₂)对盐胁迫下玉米种子萌发毒害的缓解机制,以玉米种子“先玉335”为材料,研究了外源H₂O₂对36 mmol/L NaCl胁迫下种子萌发、幼苗生长和生理指标的影响。结果表明,单独用36 mmol/L NaCl处理显著阻碍了玉米种子的萌发和幼苗生长,发芽势、发芽指数、活力指数及幼苗芽和根长度和鲜重都显著下降。用不同浓度(1、3、6、12和24 mmol/L)H₂O₂均能显著提高NaCl胁迫下玉米种子发芽势、发芽指数和活力指数,促进了幼苗芽和根的生长,增强了芽和根中CAT、SOD和APX的活性,降低MDA含量,促进了脯氨酸和可溶性糖含量的增加且6 mmol/L H₂O₂缓解盐毒害作用最好。以上结果表明,外源过氧化氢通过激活抗氧化酶活性,降低盐胁迫诱导的氧化伤害和膜损伤,提高渗透调节剂的含量,从而增强了玉米种子的抗盐性。     

Effects of hydrogen peroxide on sodium current in acutely isolated rat hippocampal CA1 neurons

AIM and METHODS: The effects of hydrogen peroxide on Na⁺ currents were studied in freshly dissociated rat hippocampal CA1 neurons using the whole-cell patch-clamp techinique. RESULTS: ①H₂O₂ caused a dose-dependent and voltage-dependent increase in the voltage-activated Na⁺ currents. The amplitudes of Na⁺ currents were increased (48.0±4.2)% and (88. 2±5. 1)% (n=10) by H₂O₂ at 10 μmol/L and 100 μmol/L, respectively. ②H₂O₂ (10 μmol/L) did not affect the activation process, but changed the inactivation process significantly. Before and after application of 10 μmol/L of H₂O₂, the half-inactivation voltage was (-64.58±1.22)mV and (-53.55±0.94)mV (n=10, P<0.01), but the slope factor was not changed. CONCLUSION: As a product of oxidation metabolism, H₂O₂ is related to some diseases in the central nervous system.     

Growing season and hydrogen peroxide effects on root induction and development in Olea europaea L. (cvs ‘Frantoio’ and ‘Gentile di Larino’) cuttings

Semi-hardwood cuttings of ‘Frantoio’ (high rooting ability) and ‘Gentile di Larino’ (low rooting ability) cultivars were obtained from 1-year-old olive shoots sampled in mid-August during the 2000 and 2001 growing season. Semi-hardwood cuttings were dipped in IBA 4000 ppm and H₂O₂ (0%-control or 3.5% w/v) solutions before rooting in greenhouse equipped with an automatic mist system. At 57 and 88 days after the beginning of rooting treatments cuttings were scored for the presence of callus, roots and roots number. In both cultivars and years, the IBA 4000+H₂O₂ treatment significantly modified rooting of cuttings at 57 days in comparison with IBA 4000 treatment. The positive effects of H₂O₂ on rooting were gradually smoothed after 88 days. At the end of the propagation cycle (88th days), cuttings treated with IBA 4000+H₂O₂ had significantly higher root number in comparison with those treated with IBA 4000 alone.     

微粒子感染对家蚕过氧化氢代谢的影响

本文探讨了100万N.b/(mm)~3感染五龄起蚕对家蚕过氧化氢代谢的影响,结果表明:①N.b感染后H_2O_2:水平后期显著增加,SOD活性差异不显著,CAT活性显著升高;②硒处理组添食N.b后H_2O_2水平与单纯添食N.b相似,SOD活性在第5、第7天显著升高,CAT活性第2、4、5天显著增加;③磁处理组添食N.b后与单纯添食N.b相比,H_2O_2含量初期显著升高,但从第5天开始显著降低而与对照接近,SOD活性初期显著降低,中后期与单纯N.b处理接近,CAT活性第6、7、9三天显著下降.N.b感染对家蚕H_2O_22代谢的最显著影响是CAT活性上升.     

氢气代谢及其环境生物修复功能研究进展

分子氢是多种微生物代谢之间相互作用的关键中介物,环境中产氢微生物和耗氢微生物的活动决定了全球氢气循环,对其他重要元素生物地球化学循环具有潜在的驱动作用。环境功能微生物在维持环境生态系统平衡、消除次生环境污染等领域中扮演着不容忽视的重要作用。因此,理解环境中氢气代谢（氢气的产生和消耗）微生物对生态环境的影响及其在环境生物修复中的作用与功能,对认识氢气的生态环境效应并将该生物能源应用于生物修复具有重要的科学意义和实践价值。系统分析了氢气代谢过程及氢化酶的分类和功能,总结了微生物产生和消耗氢气的多种途径及其对土壤生态环境效应和生物修复作用的影响,指出了目前氢气代谢过程及氢化酶应用于环境生物修复领域存在的关键科学技术问题,提出了未来的研究思路与重点方向,以推动氢气这种生物能源成就一种有前景的环境污染修复策略。     

硫氢化钠对大蒜衰老与生理特性的影响

以大蒜(Allium stativum L.)为试验材料,研究外源H2S处理对大蒜衰老与生理特性的影响.结果表明:用浓度为0、100、500、1 000、1 500 μmol/L的H2S供体NaHS浇灌处理大蒜,与对照相比,一定浓度H2S处理下,大蒜保持较高的叶绿素含量和根系活力；尤其是T2 (500 μmol/L)处理,与对照相比,显著提高了大蒜叶片抗氧化酶SOD、POD、CAT及APX活性；较高的抗氧化酶活性有利于清除大蒜叶片内活性氧,从而减轻了其对细胞膜的破坏,表现在大蒜叶片电解质渗漏率和MDA含量降低；并且大蒜叶片保持较高自由水含量,延缓大蒜的衰老.高浓度的H2S处理,不但没有延缓大蒜的衰老,反而加剧其衰老.     

高氟对动物生殖功能影响的研究概况

研究表明,摄入过量氟能使动物生殖器官的结构、超微结构等受到损伤,致使生精功能、精子生存的内环境等发生改变;还使生殖内分泌功能紊乱,性激素活性改变,进而影响生殖功能。文章概述了氟对啮齿类动物、反刍动物以及禽类的生殖功能的影响,以期了解氟对动物生殖功能的影响研究现状,为深入探讨氟的生殖毒性奠定基础。