Laboratory of Air Pollution and Global Climate Change, Department of Botany Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Ecotoxicol Environ Saf. 2019 Apr 30;171:701-708. doi: 10.1016/j.ecoenv.2019.01.030. Epub 2019 Jan 16.
Tropospheric ozone (O) has been identified as the most damaging air pollutant to crop plants in terms of growth and yield reductions. Considering the negative effect of O in tropical regions, fourteen commonly grown Indian wheat cultivars with known sensitivity to O were tested for their sensitivity/tolerance with respect to two major antioxidants (ascorbic acid and thiols) and grain yield responses against elevated O (ambient + 30 ppb) exposure. The objectives of the study were to assess the usefulness of the biochemical markers in the screening of wheat cultivars having differential level of sensitivity to O and different release time (modern and old cultivars). Ozone exposure led to an upsurge of ascorbic acid, thiols as well as their ratio greatly in the tolerant group followed by the intermediately sensitive group while least in sensitive one. Both ascorbic acid and thiol contents offered more resistance to early released cultivars compared to modern ones. Ascorbic acid served to be the most influential parameter for determining varietal response under elevated O stress and directly linked with O tolerance. Overall, the sensitive group suffered maximum yield losses while the minimum was observed in the tolerant group due to the differential enhancement of tolerance offered by antioxidants. Higher concentrations of antioxidants at early growth stages were highly correlated with final yield responses suggesting the role of antioxidants as a determinant of final yield. Findings of this study will help in the identification of O tolerant and sensitive wheat cultivars for future screening programs using ascorbic acid and thiols as important markers of O tolerance.
对流层臭氧（O）已被确定为对作物生长和产量减少最具破坏性的空气污染物。考虑到 O 在热带地区的负面影响，对 14 种常用的印度小麦品种进行了敏感性/耐受性测试，这些品种对两种主要抗氧化剂（抗坏血酸和巯基）和谷物产量对升高的 O（环境+30ppb）暴露的响应。该研究的目的是评估生物化学标志物在筛选对 O 具有不同敏感性水平和不同释放时间（现代和旧品种）的小麦品种中的有用性。O 暴露导致耐氧组的抗坏血酸、巯基及其比值大幅上升，其次是中度敏感组，而敏感组最低。与现代品种相比，抗坏血酸和巯基含量都为早期释放品种提供了更多的抗性。抗坏血酸在确定 O 胁迫下品种响应方面是最具影响力的参数，与 O 耐受性直接相关。总的来说，敏感组的产量损失最大，而耐氧组的产量损失最小，这是由于抗氧化剂提供的耐受性存在差异。在早期生长阶段，抗氧化剂浓度较高与最终产量响应高度相关，表明抗氧化剂作为最终产量决定因素的作用。本研究的结果将有助于确定 O 耐氧和敏感的小麦品种，以便未来使用抗坏血酸和巯基作为 O 耐氧性的重要标志物进行筛选计划。
