Elevated CO2 and O3t concentrations differentially affect selected groups of the fauna in temperate forest soils

Rising atmospheric CO₂ concentrations may change soil fauna abundance. How increase of tropospheric ozone (O_3t) concentration will modify these responses is still unknown. We have assessed independent and interactive effects of elevated [CO₂] and [O_3t] on selected groups of soil fauna. The experimental design is a factorial arrangement of elevated [CO₂] and [O_3t] treatments, applied using Free-Air CO₂ Enrichment technology to 30 m diameter rings, with all treatments replicated three times. Within each ring, three communities were established consisting of: (1) trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) (2) trembling aspen and sugar maple (Acer saccharum) and (3) trembling aspen. After 4 yr of stand development, soil fauna were extracted in each ring. Compared to the control, abundance of total soil fauna, Collembola and Acari decreased significantly under elevated [CO₂] (−69, −79 and −70%, respectively). Abundance of Acari decreased significantly under elevated [O_3t] (−47%). Soil fauna abundance was similar to the control under the combination of elevated [CO₂+O_3t]. The individual negative effects of elevated [CO₂] and elevated [O_3t] are negated upon exposure to both gases. We conclude that soil fauna communities will change under elevated [CO₂] and elevated [O_3t] in ways that cannot be predicted or explained from the exposure of ecosystems to each gas individually.     

Solar UV-B influences microfaunal community composition in a Tierra del Fuego peatland

The peatlands of Tierra del Fuego are subject to increased solar ultraviolet-B radiation (UV-B) due to the influence of the Antarctic ‘ozone hole’. Research into the effects of climate change and ozone depletion on peatlands has predominantly focused on the higher plant community and neglected other organisms. In the second 3-year portion of a 6-year experiment, we intensified our investigations of the response of the peatland surface microfaunal community to current and attenuated solar UV-B, and assessed possible links to changes in the microenvironment. Near-ambient UV-B and reduced UV-B treatments were realised by stretching plastic film filters that differentially attenuate UV-B over peatland sample plots. We extracted the microfauna and analysed the dissolved nutrients held within Sphagnum capitula removed from the top 1-cm of the peatland. In line with previous findings in this system, testate amoebae were more abundant under near-ambient UV-B than under reduced UV-B. Populations of the most common genus, Assulina, and other less prominent amoebae species of Heleopera and Euglypha, were consistently increased under near-ambient UV-B. Overall diversity of testate amoebae was also higher under near-ambient UV-B than under reduced UV-B, whereas rotifers, nematodes and mites were less abundant under near-ambient UV-B. Concentrations of DOC and P were generally higher under near-ambient UV-B than under reduced UV-B. These changes, combined with the changes previously reported in the plant and fungal communities, have the potential to influence peatland C storage, and surface nutrient availability. The peatland microfaunal community under near-ambient solar UV-B may be regulated by the plant community through the leaching of nutrients from leaf cells, and changes in Sphagnum morphology that affect the capitulum microenvironment.     

紫外线(UV)-B增强对植物的影响研究

对大气中臭氧层变薄的现状及紫外线划分的方法进行了介绍。综述了国内外近几十年有关UV-B辐射对植物影响的研究现状,讨论了增强的UV-B辐射对植物生长及形态结构,植物生理生化代谢,UV-B吸收物质,植物遗传物质及某些基因表达,植物细胞膜及抗氧化系统,环境多因子相互作用对植物和种群及生态系统的影响,并对该研究领域今后的研究方向进行了展望。     

臭氧对原位条件下水稻叶片光合、穗部性状及产量构成的影响

利用开顶式气室(OTCs)研究了4个水平的O3处理:过滤(charcoal filter air CF)、2×10-6mol/L(A处理)、4×10-6mol/L(B处理)和8×10-6mol/L(C处理)对原位条件下水稻叶片光合速率、气孔导度、蒸腾速率、穗部性状和产量构成的影响。结果表明,随着臭氧浓度的升高,水稻叶片的光合速率、气孔导度、蒸腾速率显著降低(P<0.05);稻穗的一次枝梗数、二次枝梗数、穗长、穗粒数明显下降(P<0.05),而小花败育率则显著上升(P<0.05);有效穗数和产量明显降低,千粒重变化不大;收获系数在低浓度O3条件下略高于CF,C处理降低7.6%;相对于CF,A处理、B处理和C处理的水稻产量分别下降了28.7%、31.8%和57.9%。由试验结果可以看出臭氧对水稻的影响是多方面的,特别是高浓度的臭氧对穗部的一次枝梗和二次枝梗分化的影响比较显著,从而影响到水稻的产量构成和产量。     

Tolerance of striped trumpeter Latris lineata embryos to ozonated seawater

The tolerance of striped trumpeter, Latris lineata (Bloch and Schneider 1801) embryos to ozonated seawater was examined as a possible means of disinfection. The effect of a range of ozone doses and exposures (CT = concentration × exposure time) was tested at different stages of embryonic development. Three-day-old embryos two-thirds developed around the yolk were exposed for 0.5, 1 or 5 min to ozone concentrations of 0.5, 1, 2 and 5 mg O₃ l⁻¹ in a fully orthogonal factorial design. For each treatment there were four replicate 250 ml containers that each received 100 ± 15 embryos. There was no significant difference in hatching success between control-treated embryos or embryos ozonated at 0.5 or 1 mg O₃ l⁻¹ for 0.5, 1 or 5 min (P < 0.05). However, hatching success was significantly reduced when embryos were treated with 2 or 5 mg O₃ l⁻¹ for 5 min or 5 mg l⁻¹ O₃ for 1 min (P < 0.05). The tolerance of embryos to 0, 0.5 or 2 mg O₃ l⁻¹ for 1 min at different stages of development (Day 0, 1, 2, 3 or 4), was then examined. An ozone concentration of 0.5 mg l⁻¹ had no effect on hatching success at any stage of development, but a concentration of 2 mg l⁻¹ significantly reduced hatching success on all days except Day 3. A safe and tested hatchery practise is to disinfect striped trumpeter embryos with 1 mg O₃ l⁻¹ for 1 min on Day 3 post-fertilisation when the embryo is two-thirds developed around the yolk.     

饮用水处理过程中微生物学安全性调查研究

通过对某饮用水厂的水处理工艺过程进行采样检测,调查研究在水处理过程中细菌等微生物学安全性指标的变化情况。研究表明,水厂采用的臭氧活性炭复合型水处理工艺可较好地保障饮用水的微生物学安全性。混凝沉淀工艺是去除微生物的关键步骤。在该工艺段,细菌、总大肠菌群、MS2和Phix174噬菌体的去除率分别高达80.53%、73.53%、99.10%和98.50%。砂滤工艺可通过物理截留作用在一定程度上去除水体中的细菌微生物,但对于粒径更小的病毒则无显著的去除效果。臭氧氧化处理可100%灭活水体中的细菌和病毒。而生物活性炭处理后出现了微生物泄露的情况,分别检出细菌总数为22 cfu/ml,MS2和Phix174效价分别为5、10 pfu/100 L。但经最后的氯化消毒处理后,水厂出水中无细菌和病毒检出。     

旋转填充床中多种高级氧化工艺的比较

基于O3的高级氧化工艺处理污水受制于O3的利用率,旋转填充床的应用能有效地提高臭氧吸收率和利用率。通过比较在旋转填充床中利用高级氧化工艺(O3,H2O2、O3/H2O2,O3/Fe2+,Fenton,O3/Fenton)对酸性红B进行脱色的效果,考察了O3/Fenton体系下H2O2和Fe2+的最佳摩尔比和Fe2+的最佳投加量,比较了在不同初始pH下各种氧化工艺的脱色效果以及在中性条件下各高级氧化工艺的脱色速率。结果表明,O3/Fenton体系下H2O2与Fe2+的最佳摩尔比为10∶1,Fe2+的最佳投加量为0.5 mmol·L-1。在低pH时O3/Fe2+与O3/Fenton相对于单独O3有着明显优势,中性时O3/Fenton体系有着最大的K值。     

Effect of electrolyzed oxidizing water and continuous ozone exposure on the control of Penicillium digitatum on tangerine cv. ‘Sai Nam Pung’ during storage

The effect of electrolyzed oxidizing (EO) water in combination with ozone to control postharvest decay of tangerine cv. “Sai Num Pung” was investigated. The spore suspension containing 10⁵ conidia ml⁻¹ of Penicillium digitatum was prepared. EO water was generated by electrolysis of various concentrations of NaCl solution (5, 25, 50% and saturated NaCl). The spore suspension was inoculated into EO water and incubated at 27 °C for 1, 2, 4, 8 and 32 min. It was found that the EO water with saturated NaCl completely inhibited the spore germination of the fungus within 1 min. When the fruits inoculated with P. digitatum were washed in EO water at the same concentrations as previous experiment for 4, 8 and 16 min and stored at 5 °C for 18 days, it was found that immersion of the fruit in EO water for 8 min was the most effective to reduce disease incidences. Moreover, washing fruit in EO water and kept in a refrigerated chamber at 5 °C with continuous ozone exposure at a concentration of 200 mg l⁻¹ for 2 h day⁻¹ to extend storage life suppressed the disease incidence until 28 days. However, none of the treatments had any effect on the quality of fruit such as total soluble solids, titratable acidity, percent weight loss and peel color. Therefore EO water may be useful for surface sanitation and ozone has potential to control the recontamination of postharvest diseases in tangerine fruit in storage room.     

结荚期喷施壳聚糖对臭氧胁迫下大豆活性氧代谢系统的影响

为揭示外源壳聚糖对O3胁迫下农作物活性氧代谢系统的影响机理,以大豆(Glycine max)为研究材料,利用开顶式气室(OTCs)研究了结荚期喷施CTS对O3胁迫下大豆叶片活性氧自由基产生速率、含量,膜脂过氧化程度,抗氧化酶活性,抗氧化物质含量及大豆籽粒产量的影响.结果表明:在整个生育期内,与对照相比,高浓度O3处理下,大豆叶片O2-. 产生速率、H2O2含量升高, MDA含量、相对电导率增大,SOD、CAT、POD活性下降,ASA、GSH含量及大豆籽粒产量降低,对大豆表现为伤害效应.结荚期喷施外源CTS后,经O3胁迫的大豆叶片O29-.产生速率、H2O2含量降低,MDA含量、相对电导率减小,SOD、CAT、POD活性升高,ASA、GSH含量以及大豆籽粒产量增加,表明外源CTS一定程度上缓解了O3胁迫对大豆的伤害,但这种缓解作用是有限的.     

臭氧与镉污染对冬小麦花后光合和产量性状的影响

本试验设置两个臭氧浓度（活性炭过滤大气-O3,〈10μg/kg;高臭氧浓度＋O3,约为80μg/kg）和两个镉浓度（-Cd,0 mg/kg;＋Cd,30 mg/kg）,采用开顶式同化箱（open-top chambers,OTCs）研究臭氧和镉双重胁迫对冬小麦（Triticum aestivumL.cv.JM22）花后光合和产量性状的影响。结果表明：花后14天,与对照相比,臭氧导致光合速率（Asat）、最大光化学效率（Fv/Fm）分别下降7.7%和3.1%;在臭氧和镉双重胁迫下,进一步下降,分别下降了15.8%和6.9%。气孔导度（Gs）以及光化学淬灭（qP）有相同变化趋势。臭氧加镉处理（O3＋Cd）又进一步降低穗粒数以及千粒重导致单穗粒重显著减少。