臭氧水浓度对鲜切菠萝品质的影响

为研究臭氧水浓度对鲜切菠萝的保鲜效果,分别采用0 mg/L、0.87 mg/L、1.1 mg/L、1.4 mg/L、1.8 mg/L的臭氧水浸泡处理鲜切菠萝2 min,装在塑料托盘中并用聚乙烯保鲜膜包裹,在冷藏(5℃)过程中每3 d测定鲜切的菌落总数、抗坏血酸、失重率、可溶性固形物和色泽。结果表明:经0 mg/L、0.87 mg/L、1.1 mg/L、1.4 mg/L、1.8 mg/L臭氧水处理的鲜切菠萝的菌落总数,在处理当天分别为5.3×105 CFU/g、9.3×104 CFU/g、2.6×104 CFU/g、3.6×103 CFU/g、2.5×103 CFU/g;第9 d分别为4.7×108 CFU/g、2.4×107 CFU/g、4.5×106 CFU/g、4.1×105 CFU/g、2.3×105 CFU/g;臭氧水处理可以抑制鲜切菠萝的褐变,减少失重和可溶性固形物消耗,对还原型抗坏血酸含量有一定影响。臭氧水处理可以延长鲜切菠萝的保质期。     

氧脱木素桦木硫酸盐浆的臭氧漂白ESCA分析

用ESCA分析了氧脱木素桦木硫酸盐浆臭氧漂白期间纸浆纤维表面特性的变化。结果表明 ,氧脱木素桦木硫酸盐浆臭氧漂白期间氧碳比逐渐增加 ,碳价态发生了显著变化。C3和C4的增加表明羰基和羧基含量的增加。ESCA是研究纸浆漂白的一种新的有效手段     

臭氧曝气对厌氧处理猪场废水磷素形态的影响

应用自行设计的臭氧深度处理装置对猪场厌氧处理废水开展曝气试验,在曝气0、10、20、40、60 min时分别取样测定各种形态磷素质量浓度。结果表明,臭氧不同曝气时间对废水体系(液体和固体)中磷素形态有显著影响。可溶性总磷、可溶性无机磷、总有机磷和颗粒态有机磷质量浓度呈下降趋势,60 min取样时分别比初始减少30.28%、41.80%、34.92%和79.53%,均达到显著性差异水平(P0.05);可溶性有机磷、颗粒态总磷、颗粒态无机磷质量浓度呈上升趋势,60 min取样时分别比初始增加105.11%、46.74%和123.86%,均达到显著性差异水平(P0.05)。60 min内通过磷化氢气态途径损失量极小,仅占废水体系总磷量的0.38%。废水体系中的总磷质量浓度基本保持不变。经臭氧消毒准备用于农田的猪场废水应考虑易被植物利用的速效磷的损失以及颗粒态磷素的回收。     

O3与CO2浓度倍增对大豆叶片及其总生物量的影响研究

利用OTC-1型开顶式气室研究CO2和O3浓度倍增对大豆叶片及其总生物量的影响结果表明,CO2和O3浓度倍增均可致使大豆黄叶率增加,绿叶率下降;CO2浓度倍增使大豆总叶片干物质量和总叶面积、绿叶和黄叶干物质量及总生物量均明显增加;O3浓度倍增使大豆总叶干物质量和总叶面积、绿叶和黄叶干物质量及总生物量均下降;CO2与O3交互作用处理对大豆生物量的影响均表现为CO2>O3;CO2与O3持续倍增处理对大豆叶片老化的影响为O3>CO2,CO2与O3逐渐达倍增的处理在大豆鼓粒前CO2的缓解作用明显,鼓粒后CO2与O3的影响逐渐接近;大豆总生物量增长遵循自然增长曲线。     

Comparison of the plant-damaging spectral solar ultraviolet radiation between three locations in Eastern USA in the year 2000

The National Ultraviolet Monitoring Center (NUVMC) maintains a network of Brewer Spectrophotometers that collect spectrally resolved, full sky ultraviolet (UV) irradiance values throughout the day. Using these data, an investigation into the spectral UV irradiances at several Brewer locations has been carried out by employing plant action spectra that represent a generalized response of plants to UV exposure. Analysis was performed for the year 2000 on the Chicago, Virgin Islands, and Shenandoah Brewer sites of the Eastern USA, which are of varying latitude, elevation, and atmospheric composition. The weighted and unweighted UV data grouped in SZA ranges of 10° increments is analyzed seasonally, highlighting the seasonal atmospheric differences between the sites. Results obtained in this paper suggest that UV data, when weighted with certain plant action spectra, show the potential sensitivity of plants to small changes in UV irradiances.     

Exchange of ozone and nitrogen oxides between the atmosphere and coniferous forest

The deposition flux of O₃ to a Douglas fir forest in the Netherlands was monitored by eddy correlation during nine months. At the same time the concentration gradients of NO, NO₂ and O₃ were determined over the forest. The canopy resistance to O₃ uptake was calculated from the measurements and it compared well with model estimates. The sensitivity of the stomatal resistance to humidity calculated in the model was adapted to improve the comparison. A multi-layered model of canopy exchange which included the influence of chemical reactions between NO and O₃ and soil emissions was used to interpret the results for NO₂. The observed fluxes of NO₂ away from the surface into the atmosphere were probably caused by soil emissions of NO. The soil-emitted NO was converted to NO₂ in the trunk space and vented into the atmosphere. The model showed that the NO₂ flux above the canopy was either away or towards the canopy depending on the strength of the soil emission and the amount of NO₂ taken up in the canopy. A canopy compensation point for NO₂ could be established above which deposition was the main process and below which emission was observed. The model calculations supported the observations which indicated a compensation point of approximately 10 ppb NO₂.     

Growth and marketable-yield responses of potato to increased CO2 and ozone

Central to the CHanging climate and potential Impacts on Potato yield and quality project (CHIP) was the consideration of the potential impacts of ozone and CO₂ on growth and yield of future European Potato crops. Potato crops, cv. Bintje, were exposed to ambient or elevated ozone; targeted daily average, 60 nl l⁻¹ for 8 h, and ambient or elevated CO_2; targeted 680 μl l⁻¹ averaged over the full growing season, in open top chambers (OTCs) at six European sites in 1998 and 1999, or to elevated CO₂ (550 μl l⁻¹) in Free Air Carbon dioxide Enrichment facilities (FACE) at two sites in both years. Some OTC experiments included 550 μl l⁻¹. Above and below ground biomass were measured at two destructive harvests; at maximum leaf area (MLA) and at final-harvest. Final-harvest fresh weight yields of marketable-size tubers, >35 mm diameter, from ambient conditions ranged from 1 to 12 kg m⁻². There was no consistent (P>0.1) CO₂×O₃ interaction for growth or yield variables at either harvest. No consistent effects of ozone were detected at the maximum-leaf-area harvest. However, at final harvest, ozone had reduced both above-ground biomass and tuber dry weight (P<0.05), particularly of the largest (>50 mm) size class. These yield losses showed linear relationships both with accumulated ozone exposure; AOT40 expressed as nl l⁻¹ h over 40 nl l⁻¹, and with yields from chambered ambient-ozone treatments (P<0.05) but, because of partial confounding between the treatment AOT40s and the ambient-ozone yields in the data, the two relationships were not completely independent. Yields from ambient-ozone treatments, however, explained a significant (P<0.01) amount of the residual variation in ozone effects unexplained by AOT40. When averaged over all experiments, mean dry weights and tuber numbers from both harvests were increased by elevated CO₂. Only green leaf number at the MLA harvest was reduced. The CO₂ responses varied between sites and years. For marketable-size tubers, this variation was unrelated to variation in ambient-CO₂ treatment yields. Yield increases resulting from the 680 μl l⁻¹ and 550 μl l⁻¹ treatments were similar. Thus elevating [CO₂] from 550 to 680 μl l⁻¹ was less effective than elevating [CO₂] from ambient to 550 μl l⁻¹. On average, CO₂ elevation to 680 μl l⁻¹ increased the dry weight of marketable-size tubers by about 17%, which far exceeded the average ozone-induced yield loss of about 5%. The net effect of raising CO₂ and O₃ concentrations on the European potato crop would be an increase marketable yield.     

Ozonation of seawater improves the survival of larval southern rock lobster, Jasus edwardsii, in culture from egg to juvenile

Phyllosoma larvae of the southern rock lobster, Jasus edwardsii, were cultured from egg to juvenile. For larvae reared from hatch to Stage III, survival was highest and bacterial contamination was lowest in seawater ozonated at low and moderate levels (400 and 500 mV oxidation-reduction potential, ORP). By contrast, at high ozonation (600 mV), all larvae suffered deformities at the moult to Stage II and terminally starved, while in unozonated water (about 300 mV), all larvae died at Stage III probably as a consequence of Vibrio bacteria proliferation. In a second experiment between Stages VI to VIII, larval survival was highest in ozonated water that had been filtered through activated charcoal and coral sand, compared to ozonated water with no filtration or filtered only through activated charcoal. Ozonated water with the combined filtration was used subsequently but there were ongoing deformities, so the level was progressively reduced from 400 mV at Stage VIII to 330 mV at Stage X, at which time ozonation was discontinued. Larvae were then cultured in unozonated water to metamorphosis of eight pueruli at 377 to 437 days after hatch, of which two survived to juvenile. Ozonation was thus effective up to Stage IX in improving culture water to minimise bacterial disease without problems of larval deformities.     

The influence of plastic composition and ventilation area on ozone diffusion through some food packaging materials

Regulatory approval of ozone has increased commercial interest in the development of applications to ensure produce quality and safety. However, ozone sometimes fails to inactivate microorganisms on packaged produce and this may be a consequence of poor diffusion into packages. Gaseous ozone (900 ± 12 μL/L) was applied to several common plastic films with a range of ventilation areas and diffusion through them determined. A semi-quantitative method using the reaction of ozone with indigo trisulfonate or with indigo carmine dye solutions was used. Dye de-colorization occurred relatively rapidly (in less than 1 h) after exposure to ozone, indicating that it diffused through all tested materials. Although the extent of ozone diffusion followed the sequence of high-density polyethylene > polypropylene > low density polyethylene, differences among them were small and not significant (P > 0.05). Ozone diffusion was also determined through a low density polyethylene film with ventilation areas of 1.3, 5.2, and 10.4% created by circular holes 6.5 mm in diameter. Gradual but modest increases in ozone diffusion occurred as the ventilation area increased.     

应用臭氧·液体菌种生产无公害金针菇技术研究

[目的]为了改变金针菇生产周期长、常规消毒药剂残留量大、对人体的刺激严重等缺点。[方法]试验设置臭氧消毒+液体菌种、甲醛消毒+液体菌种、臭氧消毒+固体菌种、甲醛消毒+固体菌种4个组合处理,以甲醛消毒+固体菌种为对照研究比较了臭氧和液体菌种的应用技术。[结果]臭氧+液体菌种组合比对照菌丝长满培养袋时间短10 d左右,产量和产品质量明显提高,污染率下降。[结论]液体菌种和臭氧消毒在金针菇生产上是值得推广的技术。