Impact of Elevated Ozone on Nutrient Uptake and Utilization of Chinese Hybrid Indica Rice (Oryza Sativa) Cultivars under Free-Air Ozone Enrichment

To assess the effects of ozone (O₃) on uptake and utilization of nitrogen, phosphorus, and potassium nutrients in rice for planning rational fertilization under projected O₃ elevation. Two hybrid indica cultivars were exposed to ambient and elevated O₃ (E-O₃) under a free-air O₃ enrichment system. E-O₃ differently affected the accumulation and distribution of biomass, and the absorption and distribution of nutrients between cultivars. These effects were related to rice cultivar and nutrient type. E-O₃ led to significantly decreased partial factor productivity and grain production efficiency (GPE) of nitrogen in both cultivars; however, the effects of E-O₃ on GPEs of phosphorus and potassium varied with cultivar. Responses of nutrients harvest indices between cultivars to E-O₃ were adverse. Differences between cultivars and elements should be considered when examining E-O₃ potentially affecting the nutrient dynamics for the purpose of reducing the amount of fertilizer applied in paddy systems to decrease potential environmental pollution.     

2-巯基苯并噻唑恒粘高性能天然橡胶耐臭氧老化的研究

高性能天然橡胶在实际生产应用中会出现贮存硬化的现象,导致了原本高性能的丧失,这一问题亟待解决。近年来研究报道了2-巯基苯并噻唑(MBT)可作为一种新型恒粘剂用于天然橡胶的恒粘处理,而关于MBT对臭氧老化性能的影响目前仍处于空白。通过加速贮存实验研究MBT对高性能天然橡胶的恒粘效果,并通过臭氧老化实验研究MBT的添加对高性能天然橡胶耐臭氧老化性能的影响。结果表明,利用MBT可制备具有较好恒粘效果的高性能天然橡胶;MBT的加入在一定量的范围内能提高橡胶的耐臭氧老化性能。     

臭氧胁迫对不同敏感型水稻叶片伤害的比较研究

【目的】研究臭氧胁迫下不同敏感型水稻叶片表观响应特征,为耐性水稻品种的选育提供参考。【方法】利用自然光气体熏蒸平台,以23个水稻品种或株系为供试材料,臭氧设置室内对照(10 n L/L)和高臭氧浓度(100 n L/L)两个处理。采用组内最小平方和动态聚类方法,根据供试材料地上部最终生物量对高浓度臭氧的响应从小到大依次分为A、B和C 3个类别,研究臭氧胁迫下不同敏感类型水稻叶片伤害指数(LBS)特别是顶3叶叶色值(SPAD值,土壤、作物分析仪器开发)的动态响应及其与最终生长量变化的关系。【结果】臭氧胁迫使A、B和C 3类水稻成熟期地上部生物量平均分别下降19%、39%和52%,后两者降幅达极显著水平。臭氧处理水稻的LBS随生育期推移呈明显的增加趋势,但不同敏感类型水稻间均无显著差异,各测定时期表现一致。与对照相比,臭氧胁迫使不同测定时期的叶片SPAD值显著下降,降幅随熏蒸时间延长和叶位下移明显增加。全生育期平均,臭氧胁迫使所有供试材料倒1叶、倒2叶和倒3叶SPAD值分别下降11%、18%和30%,均达极显著水平。与此不同,臭氧胁迫对叶片SPAD值的影响不同水稻类型间无显著差异,不同测定时期趋势相同。相关分析表明,尽管臭氧胁迫水稻成熟期地上部生物量的响应与部分测定时期LBS存在一定的相关性,但其与所有测定时期叶片SPAD值变化的相关性均不显著,不同叶位趋势一致。【结论】在本研究条件下,臭氧熏蒸叶片的伤害指数和SPAD值的响应均不宜作为水稻生长对臭氧耐性程度的评价指标。     

葡萄在散放条件下低浓度臭氧保鲜效果的研究

通过对散放条件下的葡萄进行低深度的臭氧保鲜实验，以期发现1种安全、无污染、低耗高效、易操作的新的葡萄保鲜方法。     

臭氧水去除大白菜中百菌清残留的研究

为了研究大白菜中百菌清残留经臭氧水处理后的去除效果,采用臭氧质量浓度不同和同一臭氧质量浓度浸泡时间不同处理,利用乙腈溶剂提取,固相萃取净化,毛细管柱气相色谱法分离。GC-ECD进行定性定量分析。结果显示,通入臭氧10,15,30和40min制备臭氧水质量浓度为0.99,3.48,5.26和5.64mg/L,百菌清去除率分别为14.7%,90.5%,96.7%和97.5%;说明随着臭氧水质量浓度增大,百菌清残留去除效果越好。当臭氧水质量浓度(5.2~5.3mg/L)一定时,随着浸泡时间延长,百菌清残留去除效果增加;臭氧水浸泡大白菜15min和30min,百菌清残留去除率分别为83.8%,98.3%,同样的时间以自来水做对照组浸泡,百菌清去除率分别为6.9%,18.3%,说明臭氧水去除百菌清农药的效果显著。     

工厂化循环水养殖中臭氧/紫外线反应系统的水处理性能

为增强臭氧在水产应用的安全性,满足工厂化循环水养殖对有机物去除和水体消毒的需要,该文开发O3/UV反应系统。通过试验方法研究该系统臭氧投加溶解区适宜的臭氧投加流量和处理量的关系、紫外辐射剂量配比等工艺参数,及对水质净化效果和水体消毒灭菌效果的影响等。试验结果表明:1)在满足所需水中溶解臭氧浓度的条件下,采用较低臭氧进气流量和较高进水流量有利于提高系统的臭氧溶解率和利用率。该系统在水流量为5 m3/h,臭氧投加量为(8.78±0.60)g/h时可得到水中臭氧溶解质量浓度为1.53 mg/L的臭氧水,臭氧溶解率为82.7%,臭氧利用率为97.7%。2)增加紫外灯的功率和数量均可提高对臭氧的去除率,但增加紫外灯的数量对其性能提升效果更明显。该系统在紫外剂量为1 996 MJ/cm2,对残留臭氧的去除率为83.82%。3)该系统对紫外消光度、总有机碳、水色等指标的去除率相比单独使用臭氧分别提升109.95%、89.77%和51.44%,杀菌率可达97%以上,实现工厂化循环水养殖低臭氧残留条件下的有机物有效去除和消毒杀菌。     

Does apoplastic ascorbic acid enhance manganese tolerance of Vigna unguiculata and Phaseolus vulgaris?

In cowpea (Vigna unguiculata), the development of manganese (Mn) toxicity is considered to be accompanied by the formation of reactive oxygen species, oxidized Mn, and phenoxy radicals in the leaf apoplast. Ascorbic acid (AA) is a common antioxidant in plants, and the oxidation of AA, particularly in the leaf apoplast, contributes to the first line of defence against several biotic and abiotic stress factors. The objective of the present study was to contribute to a better understanding of the role of AA in Mn leaf‐tissue tolerance of cowpea and common bean (Phaseolus vulgaris). Five cowpea cultivars (cvs.) differed greatly in Mn tolerance, which was expressed in differences in numbers of brown spots on leaves and in peroxidase (POD) activity in the apoplastic washing fluid (AWF). In a Mn‐sensitive cv., after 3 d of Mn treatment, brown spots were formed, and POD activities were increased, accompanied by a release of proteins into the apoplast. In the AWF, the concentration of AA and the ratio of AA : (AA+DHA) decreased already after 1 d, and to only 2% after 3 d. In the leaf tissue, the ratio was nearly unaffected, and the total AA+DHA content in the leaf tissue was even increased with advanced expression of Mn toxicity. The application of AA solutions in the range of 5–10 μM via the petiole slightly enhanced Mn tolerance as indicated by the reduction of brown spots (however inconsistently) and POD activity (consistently) in the AWF. Common bean cultivars differing in ozone tolerance, which has been reported to be due to a high AA availability in the leaf apoplast, were studied for their Mn tolerance. Clear differences in Mn tolerance between the cultivars existed, however, these differences were not related to their ozone tolerance. From these results, we conclude that the maintenance of sufficient AA levels in the leaf apoplast contribute to Mn tolerance, but does not fully explain genotypic differences in Mn tolerance in cowpea and common bean.     

Gradients of ozone at a forest site and over a field cropconsequences for the AOT40 concept of critical level

Ozone concentrations were measured at a wind-exposed edge of a 60 year-old 15–20 m tall Norway spruce forest in south-west Sweden and simultaneously over a barley field 5 km away for 27 days, At the forest site, measurements were performed at 3 and 13 m height 15 m in front of the forest edge, at 3 m height 15 m into the forest, and at 3 and 13 m height 45 m into the forest. Measurements at 3 m were made with three replicate tubes separated by 10 m. Differences between replicates were small. At 13 m height, the concentration (24-hr-average) 45 m into the forest was 95% of that in front of the forest edge. The average concentration at 3 m height did not vary strongly with the distance into the forest, but was 86% of that at 13 m in front of the forest edge. For AOT40 (Accumulated Exposure Over Threshold 40 ppb ozone), the differences between different positions were larger. At the 13 m level the AOT40 (day and night) was 88% of that in front of the forest 45 m into the forest. The AOT40 at 3 m was 71% of that at 13 m outside the forest. At the crop site, the ozone concentration at 1.1 m (0.1 m above the canopy), was 78% of that at 9 m (06.00–22.00). The AOT40 at 1.1 m above the ground, however, was only 50% of that at 9 m, indicating that serious errors can arise if ozone monitoring data are used uncorrnected in dose-response relationships based on measurements performed at plant height. The ozone concentration for the whole period differed very little between 9 m height at the crop site and 13 m height at the forest site outside the forest during daytime conditions (06.00–22.00). Night-time (22.00–06.00) values were only 21% at the crop site of those at the forest site due to the stronger night inversion development in the agricultural environment compared to the wind exposed forest edge. The results suggest that variations in topography and vegetation are important to consider when combining ozone monitoring data with dose-response functions.     

Bioindication of ozone in Estonia by using the tobacco variety Bel W3

The presence of tropospheric ozone was monitored by estimating necrotic flecks on the leaves of the ozone-sensitive tobacco variety Bel W3 in Estonia in 1990 and 1991. The indicator and control plants (variety Samsun) were planted in four localities (Käsmu, northern Estonia; Tartu, central Estonia, with two sites and Kooraste, southern Estonia). The percentage of the leaf area covered with necrotic flecks (necrotic index of the leaf) was determined individually for each leaf from mid-June until the end of September. The mean daily increment of the necrotic index for the period between two observations (typically 6–14 days) was calculated for each plant (NII_plant) and for the site (NII_site). The latter parameter indicates the variability of ozone episodes during the vegatation period. Ozone damage to leaves displayed an irregular pattern throughout the vegetation period, the values of NII_site ranging from 0 to 0.3 (Kooraste, 1990) and 0.9 to 2.8 (Käsmu, 1991). The average NII_site for the vegetation period was highest in northern Estonia (0.77 in 1990 and 1.47 in 1991) and lowest in southern Estonia (0.07 in 1990). High ozone damage in Käsmu can be explained by the close location (70–80 km) of the experimental site to major thermal power plants of Estonia and cities (Tallinn and Helsinki). Higher ozone damage in all the observed sites in 1991 as compared to 1990 can be accounted for different conditions for ozone formation.The number of sunny hours was 27% higher in 1991. In July the difference in sunny hours was almost twofold. It is concluded that ozone damage to plants is likely to occur in sunny summers in Estonia.     

罗氏沼虾育苗废水处理方法与工艺

运用物理、化学及生物法对罗氏沼虾育苗废水进行处理。结果表明：育苗废水经物理法（沉淀、过滤）处理后，水质状况得到改善。浑浊度平均下降68．1％，NH3-Nt、CODMn平均下降24．2％与14．4％；细菌总数、弧菌数下降68．6％和75．4％。24h后二氧化氯3．0mg／L为最佳消毒浓度；24h后溴氯海因3．0mg／L为最佳消毒浓度；48h后百杀迪1．5mg／L为最佳消毒浓度。废水经臭氧消毒14h后对细菌的杀灭率达到92．7％，对弧菌的杀灭率在5h的时候便达到了100％，氧化还原电位提高了约18．6％。消毒剂净化废水的能力依次为臭氧〉百杀迪〉溴氯海因〉二氧化氯。到一定时间当生物膜成熟后，生物滤器对水质净化有良好的效果，系统可较好保持NH3-Nt低值，而保持NO2^--N低值不易。