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21.
R. A. C. Mitchell C. R. Black S. Burkart J. I. Burke A. Donnelly L. de Temmmerman A. Fangmeier B. J. Mulholland J. C. Theobald M. van Oijen 《European Journal of Agronomy》1999,10(3-4):205-214
Spring wheat cv. Minaret crop stands were grown under ambient and elevated CO2 concentrations at seven sites in Germany, Ireland, the UK, Belgium and the Netherlands. Six of the sites used open-top chambers and one used a controlled environment mimicking field conditions. The effect of elevated CO2 for a range of N application regimes, O3 concentrations, and growth temperatures on flag leaf photosynthesis was studied. Before anthesis, flag leaf photosynthesis was stimulated about 50% by 650 compared with 350 μmol mol−1 CO2 at all sites, regardless of other treatments. Furthermore, there was no evidence of a decrease in photosynthetic capacity of flag leaves due to growth at elevated CO2 before anthesis, even for low N treatments. However, photosynthetic capacity, particularly carboxylation capacity, of flag leaves was usually decreased by growth at elevated CO2 after anthesis, especially in low N treatments. Acclimation of photosynthesis to elevated CO2 therefore appears to occur only slowly, consistent with a response to changes in sink–source relationships, rather than a direct response. Effect of elevated CO2 on stomatal conductance was much more variable between sites and treatments, but on average was decreased by ˜10% at 650 compared with 350 μmol mol−1 CO2. Carboxylation capacity of flag leaves was decreased by growth at elevated O3 both before and after anthesis, regardless of CO2 concentration. 相似文献
22.
臭氧对不同介质中弧菌的杀灭效果研究 总被引:1,自引:0,他引:1
选用飘浮弧菌、副溶血弧菌和溶藻弧菌3种弧菌作为实验材料,研究了臭氧对不同介质中弧茵的杀灭效果。结果表明,将臭氧浓度为0.27mg/L的臭氧化海水加入到不同介质中杀菌效果差异显著,在纯海水中4~6min即可达到100%的杀灭率;在可溶性淀粉(SS)浓度为40mg/L的海水中需要10min才能达到100%的杀灭率;在牛血清蛋白(BSA)浓度为40mg/L的海水中,12min后杀灭率仅为90.69%~94.07%。在海水中加入淀粉和牛血清蛋白,臭氧的杀菌效果下降,二者比较牛血清蛋白对臭氧杀菌效果的影响明显大于淀粉。 相似文献
23.
X. Carolina Lizana Susan Hess Daniel F. Calderini 《Agricultural and Forest Meteorology》2009,149(11):1964
Ozone layer depletion increases the level of ultraviolet radiation reaching the earth's surface affecting both natural and agricultural ecosystems, especially in the Southern Hemisphere. Considering the harmful effects UV-B radiation has on plant growth the future productivity of wheat crops in Southern Chile could be challenged by both (i) the forthcoming level of UV-B increase and (ii) the sensitivity of this crop to higher UV-B radiation. In this study the effect of increased UV-B radiation at different phenophases on a spring wheat cultivar (Pandora) was investigated in two experiments at plant and crop levels under out-door conditions. The experiments consisted of controls, increased UV-B radiation at specific phenophases (from 3 leaf stage to booting 3L-Bo, and from booting to maturity Bo-PM), and increased UV-B radiation for the majority of the crop cycle (from 3 leaf stage to maturity). UV-B radiation was increased by Q panel UV-313 lamps set in plastic framed structures. Control plants were grown either without frames or below the same framed structures as those which received increased UV-B treatments. Phenology, above-ground biomass, grain yield, components, grain protein concentration, leaf area index (LAI), Fv/Fm and pigments were measured at booting and/or at harvest. Above-ground biomass and yield decreased by 11–19 and 12–20%, respectively, when UV-B radiation was increased at the 3L-Bo phase, while no effect was observed when irradiation was applied later in the crop cycle (Bo-PM). No additional UV-B effects to those observed at booting were detected in plants irradiated during the majority of the entire crop cycle (3L-PM). Biomass variation was strongly associated (r = 0.99; P < 0.01) with UV-B/PAR ratio in the sensitive treatments to UV-B increases (3 L-Bo) of both experiments. Flour protein was not affected by UV-B increases at any phenophase evaluated in this study. In both experiments, leaf green area and weight were negatively affected by increased UV-B radiation and no effect on specific leaf area (SLA) was found. Lower Fv/Fm, chlorophyll, carotenoid concentration and carotenoid:chlorophyll ratio were found at crop level (experiment 2) under higher UV-B in the 3L-Bo and 3L-PM treatments. The flavonoid concentration responded differently in the two experiments, probably due to the optimum responses these pigments had to expose UV-B doses. 相似文献
24.
臭氧(O3)作为一种易降解无残留的强氧化剂广泛应用于食品保鲜。概述了臭氧对果蔬感官品质、新陈代谢、产品成熟衰老和杀菌控制采后腐败的作用,总结了臭氧在果蔬保鲜中应用的优点和局限性,并对其应用前景和研究作了展望。 相似文献
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《Journal Of Aquatic Food Product Technology》2013,22(1):111-123
Abstract The efficacy of ozonated water (0.6-1.5 ppm) was evaluated as a bactericidal agent for sanitizing food contact surfaces and for treatment of raw seafood. The presence of ozone reduced the bacterial levels substantially on stainless steel surfaces and to a lesser extent on plastic cutting boards. Ozone was about as effective as chlorine in lowering levels of Listeria innocua on inoculated food contact surfaces. Fish processing residuals present on the surface greatly reduced sanitizer effectiveness. In high organic conditions, chlorinated water was slightly more effective than ozonated water. However, ozonated water applied to fish fillets and roe was not effective for bacterial control. The presence of organic material, particularly with fillets, reduced the effectiveness of ozone. Ozone accelerated the development of rancidity in frozen roe and fillets, resulting in reduced shelf life. We recommend ozone only as a sanitizer for cleaned seafood contact surfaces. 相似文献
29.
以镁化合物、膨胀珍珠岩为原料,在室温条件下与水混合,干燥后即制得催化剂载体,通过表面负载MnSO4制备成一种新型Mn2+催化剂。该催化剂平均密度为1.03 g/cm3,略大于水,可在反应器内很好流化。电镜扫描和能谱分析表明,Mn2+在催化剂载体表面负载及催化性能稳定。对Mn2+/UV催化O3处理造纸废水进行了试验研究,结果表明,对于COD为523 mg/L的造纸废水,在催化剂投加量为20 g、O3曝气量为60 ml/min、曝气时间为40 min、pH为7、紫外灯照射功率为30 W的最佳条件下,COD去除率可达到73%以上。 相似文献
30.
[目的]研究臭氧投加量、反应时间对色度、UV254、CODcr、UV410去除的影响,为臭氧氧化工艺的实际应用提供参考。[方法]通过进气流量计调节臭氧投量,考察臭氧投量与反应时间对处理效果的影响,根据实验条件取样测定废水的色度、UV254、CODcr、UV410。[结果]臭氧氧化效果随臭氧量、反应时间的增加而增强,但增强幅度越来越小;经过多次试验得到的最佳运行参数为臭氧投加量为4.1mg/L,反应时间为10 min。[结论]污水处理厂二级生化处理出水经臭氧处理后满足再生水厂根据城市杂用水水质标准(GB/T18920-2002)、观赏性景观环境用水的再生水水质标准(GB/T18921-2002)和工业循环冷却水水质要求(GB50335-2002)确定的再生水厂出水指标。 相似文献