中文摘要：

FACE（free air gas concentration enrichment）研究使用标准的作物管理技术,在完全开放的大田条件下运行,代表了目前人类对未来大气环境的最好模拟。利用独特的大型稻田FACE平台,以典型的常规水稻品种武粳15（粳稻）和扬稻6号（籼稻）为供试材料,研究近地层臭氧（O3）浓度升高（比大气背景臭氧浓度平均增高26%）对常规水稻颖花形成的影响。结果表明：（1）高浓度O3对供试品种全穗以及一、二次枝梗颖化分化数均无显著影响;（2）高浓度O3使供试品种全穗和二次枝梗颖花退化数和退化率均显著增加,颖花退化增多是由于现存一次枝梗上二次枝梗大量退化而引起的二次颖花退化所造成;（3）颖花退化数在颖花分化数中所占比例很低,故高浓度O3对两供试品种全穗和一、二次枝梗颖花现存数以及稻穗构成均无显著影响。结合前报可知,选用常规水稻品种以及增施保花肥可能是未来近地层高浓度O3环境下稻作生产重要的适应措施。

英文摘要：

Free air gas concentration enrichment（FACE） experiment,conducted in fully open-air field condition using regional standard agronomic practices,represents the best simulations of future atmospheric environment.To investigate the impact of high ozone concentration（[O3]） on spikelet differentiation and degeneration of inbred rice cultivars,an experiment using a unique free-air ozone concentration enrichment（ozone-FACE） system was conducted in Yangzhou,China.Two typical inbred rice cultivars,Wujing15（Japonica,WJ15） and Yangdao 6（Indica,YD6）,were grown at ambient and elevated[O3]（ca.26% above ambient）.The results showed that（1）Elevated [O3] had no effect on the number of differentiated spikelets per panicle,and the number of differentiated spikelets on primary branches（PB） and secondary branches（SB） per panicle of two inbred rice cultivars.（2）Both inbred rice cultivars showed significant increases in the number of degenerated spikelets per panicle,the number of degenerated SB spikelets per panicle,the percentage of degenerated spikelets and the percentage of degenerated SB spikelets to total spikelets,due to ozone exposure.The O3-induced increasing in the number of degenerated spikelets was mainly attributed to the increased number of degenerated SB spikelets on degenerated SB of surviving PB.（3）Since the number of degenerated spikelets accounts only small portion of the differentiated spikelets,the number of（surviving）spikelets per panicle,the number of PB or SB spikelets per panicle of two cultivars were not significantly affected by elevated[O3],which resulted in no change in panicle composition.These results,together with fingdings from our previous studies,suggest that the selection of inbred rice cultivars with high yield and applying more fertilizers during rice flowering stage might be an important adaptation strategy to reduce yield loss in future atmospheric environment with increasing surface[O3].