State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, 20 Nanxincun, 100093, Beijing, PR China.
J Exp Bot. 2011 Aug;62(12):4153-62. doi: 10.1093/jxb/err104. Epub 2011 Apr 28.
Recent reports challenge the widely accepted idea that drought may offer protection against ozone (O(3)) damage in plants. However, little is known about the impact of drought on the magnitude of O(3) tolerance in winter wheat species. Two winter wheat species with contrasting sensitivity to O(3) (O(3) tolerant, primitive wheat, T. turgidum ssp. durum; O(3) sensitive, modern wheat, T. aestivum L. cv. Xiaoyan 22) were exposed to O(3) (83ppb O(3), 7h d(-1)) and/or drought (42% soil water capacity) from flowering to grain maturity to assess drought-induced modulation of O(3) tolerance. Plant responses to stress treatments were assessed by determining in vivo biochemical parameters, gas exchange, chlorophyll a fluorescence, and grain yield. The primitive wheat demonstrated higher O(3) tolerance than the modern species, with the latter exhibiting higher drought tolerance than the former. This suggested that there was no cross-tolerance of the two stresses when applied separately in these species/cultivars of winter wheat. The primitive wheat lost O(3) tolerance, while the modern species showed improved tolerance to O(3) under combined drought and O(3) exposure. This indicated the existence of differential behaviour of the two wheat species between a single stress and the combination of the two stresses. The observed O(3) tolerance in the two wheat species was related to their magnitude of drought tolerance under a combination of drought and O(3) exposure. The results clearly demonstrate that O(3) tolerance of a drought-sensitive winter wheat species can be completely lost under combined drought and O(3) exposure.
最近的报告挑战了广泛接受的观点，即干旱可能会对植物中的臭氧 (O(3)) 损害提供保护。然而，人们对干旱对冬小麦物种臭氧 (O(3)) 耐受性大小的影响知之甚少。两种对臭氧 (O(3)) 敏感性不同的冬小麦物种（对臭氧 (O(3)) 耐受性强的原始小麦，T. turgidum ssp. durum；对臭氧 (O(3)) 敏感的现代小麦，T. aestivum L. cv. Xiaoyan 22）在开花到成熟期间暴露于臭氧 (O(3))（83ppb O(3)，7h d(-1)) 和/或干旱（42%土壤水容量）下，以评估干旱对臭氧 (O(3)) 耐受性的诱导调制。通过测定体内生化参数、气体交换、叶绿素 a 荧光和籽粒产量来评估植物对胁迫处理的反应。原始小麦比现代品种表现出更高的臭氧 (O(3)) 耐受性，而后者比前者表现出更高的耐旱性。这表明，当这两个物种/冬小麦品种分别施加这两种胁迫时，它们之间没有交叉耐受性。原始小麦失去了臭氧 (O(3)) 耐受性，而现代品种在干旱和臭氧 (O(3)) 联合暴露下表现出对臭氧 (O(3)) 耐受性的提高。这表明这两个小麦物种在单一胁迫和两种胁迫的组合之间存在不同的行为。这两个小麦物种的观察到的臭氧 (O(3)) 耐受性与其在干旱和臭氧 (O(3)) 联合暴露下的耐旱性大小有关。结果清楚地表明，在干旱和臭氧 (O(3)) 联合暴露下，对干旱敏感的冬小麦品种的臭氧 (O(3)) 耐受性可能完全丧失。
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