臭氧处理和低温保藏对黄鱼保鲜效果

探讨臭氧水及低温保藏对黄鱼的保鲜效果。分别使用098、312和468mg/L 3种浓度的臭氧水对冰鲜黄鱼进行处理,浸泡时间分别为5、10和15min,低温4℃下贮藏至10d。结果表明,臭氧浓度越高、浸泡时间越长,杀菌及保鲜效果越好。使用浓度为468mg/L的臭氧水浸泡处理黄鱼15min后杀菌效果最好,其TVB-N值第6天为2353mg/100g,结合感官指标,黄鱼保鲜期比对照延长2d。试验结果表明,臭氧水可有效用于黄鱼的保鲜。     

应用臭氧浓度精准控制熏蒸装置提高树莓贮藏品质

为了明确不同浓度臭氧气体处理对树莓低温贮藏品质的影响,促进臭氧精准控制装置在果蔬采后贮藏保鲜中的应用,采用国家农产品保鲜工程技术研究中心(天津)研制的精准浓度臭氧冷藏熏蒸装置对树莓(品种:海尔特兹Heritage)进行短时臭氧熏蒸处理(4℃,1 h,相对湿度95%),臭氧质量浓度为0.21、0.54、1.07 mg/L,熏蒸后树莓置于0℃冷库中贮藏,定期测试不同浓度臭氧熏蒸处理对树莓采后贮藏品质的影响。结果表明:臭氧精准控制装置能够在较短时间内达到设定浓度,0.21、0.54、1.07 mg/L的臭氧分别在96、168、240 s时达到,并且臭氧浓度控制精准,精度为0.05 mg/L。不同浓度臭氧熏蒸处理均可以显著抑制树莓微生物繁殖(P0.05),1.07 mg/L可使树莓微生物菌落总数降低1.62个数量级。0.21、0.54 mg/L熏蒸处理过的树莓感官品质显著好于对照组(P0.05),能够有效延缓树莓果实维生素C降解,维持可滴定酸、可溶性固形物含量,抑制硬度下降,0.54 mg/L熏蒸处理对树莓的保鲜效果较佳,1.07 mg/L熏蒸处理对树莓表面造成轻微伤害,反而促进树莓贮藏中的腐烂,降低了营养品质,不利于树莓保鲜。精准控制臭氧浓度,对于明确臭氧处理保鲜效果、调控树莓采后贮藏品质方面具有应用潜力。     

臭氧处理对切分青椒贮藏品质的影响

为了探讨臭氧气体对切分蔬菜贮藏品质的影响,该文以青椒为材料,分别研究了2.14、4.28、6.42和8.56mg/cm3质量浓度臭氧气体处理下切分青椒在5～8℃贮藏条件下的硬度、叶绿素含量、Vc的含量、菌落总数和感官品质的变化。试验结果表明:适当浓度的臭氧处理可显著抑制切分青椒叶绿素含量、Vc含量、感官品质和硬度的下降,并对微生物有明显的杀灭作用;以6.42mg/cm3臭氧质量浓度下处理15min,切分青椒5～8℃下贮藏6d感观评价得分为32分,基本保持了新鲜青椒色、味、香品质;2.14mg/cm3的处理组臭氧浓度过低保鲜效果不明显,8.56mg/cm3的处理组因臭氧浓度过高,贮藏效果低于未处理组。研究结果可为切分蔬菜的保鲜贮藏提供参考。     

臭氧杀灭循环营养液中三种土传病原菌的试验

为给臭氧应用于循环营养液消毒提供指导，该文研究了营养液中臭氧浓度的上升、衰减，臭氧杀灭营养液中3种植物病原菌所需的残余臭氧浓度、接触时间和残留臭氧对黄瓜根系的伤害。结果表明：高浓度臭氧气体在营养液中形成的臭氧平衡浓度高，达到平衡浓度所需的时间短；低浓度臭氧气体形成的臭氧平衡浓度低，达到平衡浓度需要的时间长。当营养液中残余臭氧浓度为0.6 mg/L，接触时间5 min时，臭氧对10³ cfu/mL浓度黄瓜枯萎病、番茄枯萎病和10⁶ cfu/mL浓度十字花科软腐病3     

切片莲藕臭氧保鲜呼吸模型的研究

为了研究臭氧保鲜包装理论,根据果蔬呼吸作用与薄膜透气特性的相互关系,建立了以臭氧作为保鲜气体的果蔬呼吸数学模型,并以切片莲藕作包装物、聚乙烯尼龙复合（PA/PE）膜作包装袋为例,利用遗传算法（GA）对呼吸模型中的参数进行了识别。另外,根据已建立的呼吸模型,通过仿真模拟出不同温度条件下袋内气体浓度的变化。结果表明7.5℃下模拟值与实测值能够很好地吻合,从而模拟值可为臭氧对果蔬保鲜包装设计提供理论指导。     

冰温结合臭氧对销地红提葡萄保鲜效果研究

为确定冰温(-1℃)条件下红提葡萄贮藏保鲜的适宜臭氧浓度,分别以2.5mg·L-1和5mg·L-1质量浓度的臭氧对冰温下贮藏的红提葡萄进行间歇式处理,并在贮藏期间定期对葡萄的品质和生理指标进行测定。结果表明,臭氧有很好的抑菌效果。与对照相比,臭氧组降低了葡萄的腐烂率、落粒率,延缓了可溶性固形物(SSC)和可滴定酸(TA)含量的下降,其中低质量浓度的臭氧(2.5mg·L-1)较高浓度(5mg·L-1)具有更好的保鲜效果。因此冰温条件下,红提葡萄贮藏保鲜的适宜臭氧浓度为2.5 mg·L-1。该研究为筛选葡萄安全有效、经济实用的非硫保鲜方法提供了参考。     

臭氧污染对不同品种小麦磷素吸收与分配的影响

利用中国稻麦轮作O3-FACE（Free air O3 concentration enrichment）试验平台,研究了小麦（Tritcium aestivum L.）品种的物质积累、磷素的吸收与分配对大气臭氧浓度增加的响应。结果显示,大气臭氧浓度增加50%对供试小麦根和地上部的生物量积累影响差异较大,显著降低了扬麦16、烟农19和嘉兴002的产量,降幅为13.2%-35.7%,但对扬麦15和扬幅麦2号的产量无显著影响。臭氧增加导致5种小麦根系和地上部植株中磷含量呈下降趋势,而籽粒中磷含量却无显著变化。臭氧污染降低了磷在小麦根和籽粒中的积累量,促使小麦植株中磷由根部向地上部转移,增加了籽粒中磷所占比重。高臭氧浓度下扬麦16、烟农19和嘉兴002的磷偏生产力降低9.0-23.8（kg/kg, P2O5）, 磷素利用率显著降低8.2%-20.2%,但扬麦15和扬幅麦2号的磷素偏生产力与利用效率变化不明显。以上结果表明,臭氧污染具有改变小麦物质分配, 影响土壤磷素在土壤-植物系统周转的潜在风险。     

地表臭氧胁迫对大豆干物质生产和分配的影响

利用结构、性能完全相同的9个开顶式气室（OTC）,开展了大田试验条件下地表臭氧浓度增加对大豆干物质（DM）生产和产量的影响研究。实验设置三个处理：CK为未经处理的空气,T1处理的O3浓度为100nL.L^-1,T2处理的O3浓度为150nL.L-1。结果表明：不同浓度臭氧熏气下,不同生育期大豆干物质重、根瘤数、根瘤干重,鼓粒期根茎的转运率和移动率均显著下降（P〈0.05）。100nL.L^-1臭氧处理对叶片转运率和鼓粒期-成熟期干物质生产速率影响不显著;150nL.L^-1臭氧熏气下,大豆结荚出现时间推迟,叶片转运率和鼓粒期-成熟期干物质生产速率均显著下降。臭氧浓度升高显著降低大豆的单株粒数、粒重及产量,但对百粒重没有显著影响。以上结果表明,100nL.L^-1臭氧熏气下大豆产量显著下降的主要原因是干物质生产速率下降;而150nL.L^-1臭氧熏气下大豆产量显著下降,是由于干物质转移受抑制和干物质生产速率下降共同导致的。     

水稻气孔臭氧通量拟合及通量与产量关系的比较分析

利用田间原位开顶式熏气装置（Open-Top Chambers,OTCs）,研究了5种不同浓度臭氧（O3）处理下（自然大气处理,AA;箱内大气处理,NF;箱内低浓度O3处理,NF＋30nL·L-1;箱内中等浓度O3处理,NF＋60nL·L-1;箱内高浓度O3处理,NF＋90nL·L-1）我国珠三角地区水稻产量损失与累积气孔O3通量（AFstX）和累积O3浓度（AOT40和SUM06）的关系,同时利用边界线拟合法,分析了不同环境因子作用下水稻剑叶气孔导度的变化特征。结果表明：水稻气孔运动的光饱和点和最适温度分别约为500μmol·m-2·s-1和33.1℃,水汽压差、物候期和O3暴露剂量的气孔限制临界值分别约为1.3kPa、500℃·d和5μL·L-1·h,高于此临界值时,气孔导度会明显下降。利用Jarvis气孔导度模型对水稻剑叶气孔导度和气孔O3吸收通量进行了预测,结果表明Jarvis模型解释了水稻实测气孔导度61%的变异性。O3吸收速率临界值（X）为2nmol·m-2·s-1时,累积气孔O3吸收量（AFst2）与水稻产量的相关性最高（R2=0.63）,明显高于O3浓度指标（AOT40和SUM06）与水稻产量的相关性（R2值分别为0.49和0.51）,表明基于气孔通量的O3风险评价指标能更好地反映水稻产量的变化。     

大气臭氧浓度升高对大豆籽粒C、N、P和K浓度的影响

为明确大气臭氧浓度升高对大豆籽粒C、N、P和K元素浓度的影响,本研究以环境大气臭氧浓度为对照,利用开顶式气室模拟大气臭氧浓度升高40 nL·L^-1的环境条件,选取3个推广面积较大的大豆品种:东生1号、绥农4号和绥农8号,解析了在高臭氧浓度下不同大豆品种籽粒C、N、P和K元素浓度及计量化学比的变化。结果表明,臭氧浓度升高会降低大豆籽粒中C元素和P元素浓度,但增加了N元素和K元素浓度,3个品种大豆籽粒中C、P元素平均浓度分别降低了1.51%和10.7%;N、K元素平均浓度则分别升高了37.8%和11.0%。虽然大豆籽粒C、N、P和K元素浓度存在品种间差异(P<0.05),但臭氧与品种交互作用对4种元素的积累影响不显著(P>0.05)。臭氧浓度升高还会改变大豆籽粒中C、N、P和K元素化学计量比,如提高C/N和C/K,降低C/P和N/P,同时提高P/K,这表明臭氧浓度升高降低了N和K的元素利用效率,而且大豆对N元素的积累和利用可能受到P元素的制约。     

水中臭氧浓度的检测及三种液体中臭氧的稳定性

为了研究臭氧在水中的衰减行为,采用靛蓝二磺酸钠法和碘化钾法测定水中的臭氧浓度.其中靛蓝二磺酸钠法,在pH值2.0条件下,48 h内空白的吸光度降低了3%,含样品溶液的吸光度降低了40%;在pH值6.8条件下分别降低了1%和2%;在pH值11.9条件下分别降低了83%和52%.该法测定水中臭氧含量的应用条件仍需研究.用碘化钾法测定时发现,蒸馏水中臭氧浓度变化的总体趋势是衰减的,臭氧浓度在曝气停止后大约42 min前后衰减速度不同,在42 min以前衰减较快,之后一直到3h内基本稳定;自来水和营养液中60 min内臭氧浓度变化的总趋势是稳定的,与蒸馏水中表现不同;3种液体中的臭氧浓度的高低顺序是蒸馏水中(约15 mg/L)>自来水中(约10 mg/L)>营养液中(约3 mg/L).     

水中臭氧浓度的检测及三种液体中臭氧的稳定性

为了研究臭氧在水中的衰减行为，采用靛蓝二磺酸钠法和碘化钾法测定水中的臭氧浓度。其中靛蓝二磺酸钠法，在pH值2.0条件下，48 h内空白的吸光度降低了3%，含样品溶液的吸光度降低了40%；在pH值6.8条件下分别降低了1%和2%；在pH值11.9条件下分别降低了83%和52%。该法测定水中臭氧含量的应用条件仍需研究。用碘化钾法测定时发现，蒸馏水中臭氧浓度变化的总体趋势是衰减的，臭氧浓度在曝气停止后大约42 min前后衰减速度不同，在42 min以前衰减较快，之后一直到3h内基本稳定；自来水和营养液中60 min内臭氧浓度变化的总趋势是稳定的，与蒸馏水中表现不同；3种液体中的臭氧浓度的高低顺序是：蒸馏水中(约15 mg/L)>自来水中(约10 mg/L)>营养液中(约3 mg/L)。     

Benzothiadiazole-induced resistance modulates ozone tolerance

The effects of ozone on bean plants pretreated with the SAR activator benzothiadiazole (BTH) have been investigated after fumigations with an acute dose of the pollutant (200 nL x L(-1) for 4 h), carried out at different times from BTH application. BTH pretreatment induced opposite effects on bean susceptibility to O(3), depending on the time elapsed before fumigation. When this time was only 1-2 days, bean plants were more susceptible to O(3) than untreated controls, showing rapid and extensive cell death in both palisade and spongy mesophyll. These damages appeared to be closely correlated with the amount and localization of H(2)O(2) in the leaf tissues. In BTH-pretreated, but not fumigated, plants, H(2)O(2) accumulation occurred in the cell walls and no dead cells were detected, whereas O(3) fumigation of untreated plants produced H(2)O(2) accumulation also inside some palisade mesophyll cells, causing their death. When BTH pretreatments were carried out 5-7 days before fumigation, plants appeared to be more tolerant to O(3) compared to untreated controls. Under these conditions, no visible symptoms of phytotoxicity were observed for at least 2 weeks after fumigation and no H(2)O(2) accumulation was detected. Biochemical assays showed a significant increase in the ascorbate (AA) level, taking place from the fifth to the seventh day after BTH treatment and unaffected by O(3) when given at these times. Ascorbate peroxidase (APX) activity appeared to decrease during the first 2 days after BTH treatment, and the decrease was somewhat enhanced by fumigation. On the contrary, guaiacol peroxidase (GuPX) activity was found to steadily increase up to the fifth day after BTH treatment but showed a bimodal trend upon fumigation. These results suggest that, during the first 1-2 days after BTH application, the H(2)O(2) level is enhanced by O(3) over a critical threshold for cell viability. However, in the absence of the pollutant, H(2)O(2) decreases in the following days under the effect of AA accumulation and increased GuPX activity. As GuPX is known to promote cell wall lignification and protein cross-linking, these effects would protect plasmalemma from O(3) irreversible damage, provided the priming by BTH has been fully developed.     

Impact of ozone on grain sorghum yield

Grain sorghum (Sorghum vulgare Pers.) is an important animal feed crop, and it is sometimes planted as a substitute for field corn. Although sorghum is grown in areas of the central and southern U.S. where potentially damaging concentrations of O₃ exist, no data are available regarding the sensitivity of grain sorghum to O₃. Plants of grain sorghum (DeKalb A28+ ) were field-grown in open-top chambers and exposed to O₃(7-hr day^?1 seasonal mean concentrations of 0.016, 0.040, 0.059, 0.078, 0.102, and 0.129 ppm) for 85 days to determine the impact of O₃ on grain yield. A randomized complete block design incorporated three replicates of all treatments. Foliar injury was noted at the two highest 03 treatments. Analysis of variance of the data indicated highly significant O₃ effects on overall grain yield. There was a general decrease in yield as O₃ increased, and the overall grain yield reductions were caused primarily by reductions in individual seed weight. Quadratic, Weibull, and plateau-linear models all adequately described the response of grain sorghum to O₃. Yields were not markedly affected at O₃ concentrations below the 0.10 ppm treatment, and the predicted yield loss of 15% at a seasonal 7-hr mean O₃ concentration of 0.13 ppm indicates that grain sorghum exhibits considerable tolerance to O₃.     

Effects of ozone on calcareous grassland communities

A system of 16 open-top chambers was used to investigate the effects of a range of ozone concentrations typical of those found in southern Britain on the species composition of calcareous grassland communities. Two experimental approaches were adopted: the first involved the use of artificial communities of species typical of calcareous grasslands, whilst the second involved semi-natural chalk grassland swards transplanted from the field. Elevated ozone had little effect on total biomass of the artificial communities, but did significantly alter the species composition. The proportion of forbs decreased linearly with increased ozone exposure above 40ppb. Species composition was stable in the transplanted swards receiving filtered air, whilst there was a shift towards what appeared to be a more calcareous grassland community in the swards treated with higher ozone exposures. Thus, both experiments provide evidence that ambient levels of ozone in southern Britain can cause changes in species composition of semi-natural calcareous grassland communities.     

Biomonitoring ozone phytotoxicity in eastern Spain

High ozone (O₃) levels have been recorded in eastern Spain. A project was developed to identify the areas of elevated O₃ and determine if these levels were above critical concentrations for plant damage. Thus, a network of bioindicators was established in two Autonomous Communities of Spain: Catalunya (31.930 km²) and Valencia (23.305 km²) to assess O₃ phytotoxicity. Three tobacco cultivars, (Bel-W3, Bel-C and Bel-B) were used during the 1994 growing season in both Regions. In Catalunya the highest O₃ phytotoxicity was recorded in coastal areas, while the phytotoxicity decreased as plants were grown further in-land. A lower O₃ phytotoxicity was observed in coastal sites of the Valencia Autonomous Community, compared to Catalunya, although the O₃ injury was observed downwind from Valencia city in the most resistant cultivar Bel-B. The results in the Valencian Community were difficult to interpret, since plant viruses were widely distributed, not only in indicator plants, but also in commercial crops grown in the area. The analysis of O₃ concentrations, meteorological parameters and visible injury at the Catalan sites showed that high relative humidity levels could favour O₃ phytotoxicity. Therefore, the interactions between O₃ exposure and environmental conditions on plant response should be further studied for the establishment of sound critical levels.     

Towards unravelling the complex interactions between microclimate,ozone dose,and ozone injury in clover

This paper describes the results of a series of experiments designed to identify the relative importance of various factors which modify the responses of a sensitive species to ozone. The experiments were conducted in a closed chamber exposure system, enabling clover plants (Trifolium subterraneum L. cv Geraldton) to be exposed to ozone doses ranging from 0 to 1800 ppb.h, accumulated over 40 ppb (AOT40), for 7 h d^?1, over 1 to 3 days. Microclimatic conditions during exposure ranged from 80 to 460 μmol m^?2 s^?1 photosynthetically active radiation (PAR), 26 to 61 percent relative humidity (%RJH) and 16 to 36 °C temperature. No clear dose response relationships were established for 1, 2 or 3 day exposures due to the influence of microclimatic and other factors during exposure. Artificial Neural Networks were used as a tool to identify patterns within the dose response data set and to clarify the effects of various microclimatic and dose topography responses, during multiple day exposures. Analysis of the trained neural network revealed that AOT40 on individual exposure days was the most important influences PAR on the first and third days of exposure, the mean relative humidity and the mean temperature for all days also had strong influences. Leaf age also had an influence but this was weaker. This paper describes these results in relation to the influences acting upon the plant and how these affect ozone uptake and resulting ozone injury.     

Foliar sensitivity of pinto bean and soybean to ozone as affected by temperature,potassium nutrition and ozone dose

Pinto bean (Phaseolus vulgaris L.) and soybean [Glycine max (L.) Merv.] were exposed to O₃ to determine the interactions of growth temperature, exposure temperature, K nutrition and doses of O₃ on their foliar sensitivity. Pinto bean developed more foliar injury than soybean. Pinto bean were most sensitive when grown and exposed at 28°C. Growth and exposure temperature interacted in the development of foliar injury on pinto bean, but only growth temperature influenced the amount of foliar injury on soybean. Both species developed more foliar injury when grown with low K nutrition. There was no relationship between foliar injury and reducing sugars or sucrose content of the leaves.     

稻草秸秆的碱性臭氧预处理效果

为了研究碱性臭氧预处理对稻草秸秆酶水解、表观结构及成分的影响,将稻草秸秆碱性臭氧预处理后进行酶水解,对处理前后的稻草秸秆进行了扫描电镜观察及成分分析,并对处理后溶液进行了紫外光谱分析。结果表明：碱性臭氧预处理能将稻草秸秆中的木质素氧化降解为小分子的有机酸,降低了稻草秸秆中木质素的含量,提高了纤维素的含量。扫描电镜观察显示经碱性臭氧预处理过的稻草秸秆,机械组织暴露,孔隙度大,酶解的有效比表面积大。在pH值5.0、每单位底物加酶量31.2 mg/g、45℃条件下,碱性臭氧预处理稻草秸秆酶水解120 h时还原糖达到了902 mg/g,糖化率为92.57%。在相同酶解条件下,碱性预处理与未处理稻草秸秆的糖化率分别为74.90%与53.53%。碱性臭氧预处理稻草秸秆的糖化率明显高于碱性预处理与未处理稻草秸秆的糖化率。     

Absorption of ozone onBetula pendula Roth leaf surface

Leaf cuticular surface absorption of O₃ was investigated inBetula pendula Roth leaves which have no stomata on their adaxial surface. A two-component absorption model was assumed to approximate experimental data. The first component, having second order kinetics, decreased exponentially during ozonation, the second or residual component remained constant. The residual ozone conductance of the leaf cuticle was about an order of magnitude higher than the leaf cuticular conductance to water vapour. It is concluded that leaf surface absorption must be taken into consideration during short term experiments and in those with low ozone concentrations.