To clarify the effects of ozone (O3) on the resistance of Japonica rice (Oryza sativa L.) to root lodging, the Japanese major rice cultivar Koshihikari was exposed to four levels of O3 in open-top chambers (mean O3 concentration: 17.3, 32.4, 51.1, and 66.3 nl l). We evaluated the resistance to root lodging by measuring pushing resistance at 15 days after heading (DAH) and the dry masses of plant organs such as roots at harvest (35 DAH). Exposure to O3 significantly reduced pushing resistance per panicle, suggesting that the O3 reduced resistance to root lodging. Because the degree of O3-induced reduction in pushing resistance per panicle correlated with that of O3-induced reduction in root dry mass per panicle, the O3-induced reduction in the resistance to root lodging could be caused by O3-induced reduction in root development. There was a significant negative correlation between relative value of pushing resistance per panicle and O3 concentration or dose, indicating that resistance to root lodging decreases with increasing O3 concentration. In East Asia, because the O3 concentration is projected to increase in the near future, lodging issues in the rice cultivation could become serious.

中文翻译：

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对流层臭氧降低粳稻 ( Oryza sativa L., cv. Koshihikari) 的抗倒伏性

为了阐明臭氧 (O3) 对粳稻 (Oryza sativa L.) 抗根倒伏能力的影响，日本主要水稻品种越光在开顶室中暴露于四级 O3（平均 O3 浓度：17.3， 32.4、51.1 和 66.3 nl l)。我们通过测量抽穗后 15 天的推力 (DAH) 和收获时根等植物器官的干质量 (35 DAH) 来评估根部倒伏的抗性。暴露于 O3 显着降低了每穗的推抗力，表明 O3 降低了根倒伏的抗性。由于 O3 诱导的每穗推抗力降低的程度与 O3 诱导的每穗根干质量减少的程度相关，因此 O3 诱导的根倒伏抗性降低可能是由 O3 诱导的根发育减少引起的. 每穗抗倒伏性相对值与O3浓度或剂量呈显着负相关，表明抗根倒伏性随O3浓度增加而降低。在东亚，由于 O3 浓度预计在不久的将来会增加，水稻种植的倒伏问题可能会变得严重。