Ashrafuzzaman Md, Lubna Farzana Afrose, Holtkamp Felix, Manning William J, Kraska Thorsten, Frei Michael
Institute of Crop Sciences and Resource Conservation (INRES) Plant Nutrition, University of Bonn, Bonn, Germany; Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet, Bangladesh.
Institute of Crop Sciences and Resource Conservation (INRES) Plant Nutrition, University of Bonn, Bonn, Germany.
Environ Pollut. 2017 Nov;230:339-350. doi: 10.1016/j.envpol.2017.06.055. Epub 2017 Jun 29.
Rising tropospheric ozone concentrations in Asia necessitate the breeding of adapted rice varieties to ensure food security. However, breeding requires field-based evaluation of ample plant material, which can be technically challenging or very costly when using ozone fumigation facilities. The chemical ethylenediurea (EDU) has been proposed for estimating the effects of ozone in large-scale field applications, but controlled experiments investigating constitutive effects on rice or its suitability to detect genotypic differences in ozone tolerance are missing. This study comprised a controlled open top chamber experiment with four treatments (i) control (average ozone concentration 16 ppb), (ii) control with EDU application, (iii) ozone stress (average 77 ppb for 7 h daily throughout the season), and (iv) ozone stress with EDU application. Three contrasting rice genotypes were tested, i.e. the tolerant line L81 and the sensitive Nipponbare and BR28. The ozone treatment had significant negative effects on plant growth (height and tillering), stomatal conductance, SPAD value, spectral reflectance indices such as the normalized difference vegetation index (NDVI), lipid peroxidation, as well as biomass and grain yields. These negative effects were more pronounced in the a priori sensitive varieties, especially the widely grown Bangladeshi variety BR28, which showed grain yield reductions by 37 percent. EDU application had almost no effects on plants in the absence of ozone, but partly mitigated ozone effects on foliar symptoms, lipid peroxidation, SPAD value, stomatal conductance, several spectral reflectance parameters, panicle number, grain yield, and spikelet sterility. EDU responses were more pronounced in sensitive genotypes than in the tolerant L81. In conclusion, EDU had no constitutive effects on rice and partly offset negative ozone effects, especially in sensitive varieties. It can thus be used to diagnose ozone damage in field grown rice and for distinguishing tolerant (less EDU-responsive) and sensitive (more EDU-responsive) genotypes.
亚洲对流层臭氧浓度不断上升，因此需要培育适应的水稻品种以确保粮食安全。然而，育种需要对大量植株材料进行田间评估，而使用臭氧熏蒸设施进行评估在技术上具有挑战性或成本非常高。已有人提议使用化学物质乙二脲（EDU）来评估臭氧在大规模田间应用中的影响，但目前尚缺乏关于其对水稻的组成效应或检测臭氧耐受性基因型差异适用性的对照实验。本研究包括一项受控的开顶式气室实验，设置了四种处理：（i）对照（平均臭氧浓度16 ppb），（ii）施用EDU的对照，（iii）臭氧胁迫（整个季节每天7小时平均77 ppb），以及（iv）施用EDU的臭氧胁迫。测试了三种对比鲜明的水稻基因型，即耐性品系L81以及敏感型的日本晴和BR28。臭氧处理对植株生长（株高和分蘖）、气孔导度、SPAD值、光谱反射指数如归一化植被指数（NDVI）、脂质过氧化以及生物量和谷物产量均有显著负面影响。这些负面影响在先验敏感品种中更为明显，尤其是广泛种植的孟加拉品种BR28，其谷物产量降低了37%。在没有臭氧的情况下，施用EDU对植株几乎没有影响，但部分减轻了臭氧对叶片症状、脂质过氧化、SPAD值、气孔导度、几个光谱反射参数、穗数、谷物产量和小穗不育的影响。敏感基因型对EDU的反应比耐性L81更明显。总之，EDU对水稻没有组成效应，且部分抵消了臭氧的负面影响，尤其是在敏感品种中。因此，它可用于诊断田间种植水稻的臭氧损伤，并区分耐性（对EDU反应较小）和敏感（对EDU反应较大）基因型。
