近地层臭氧(O_3)浓度升高对水稻武运粳21抗倒性的影响

Impacts of tropospheric ozone concentration enrichment on lodging resistance of rice Wuyunjing 21

依托独特的稻田臭氧FACE(Free air gas concentration enrichment,开放式空气中气体浓度增高)系统平台,以武运粳21为供试水稻品种,设置正常浓度O3(即大气背景浓度)和高浓度O3(实际比大气背景浓度增高25%左右),定量研究地表O3浓度升高对粳稻抗倒能力的影响。结果表明:高浓度O3对水稻抽穗期和抽穗后20 d基部节间的抗折力和弯曲力矩没有显著影响,但使成熟期基部节间的抗折力和弯曲力距有所降低。因此,臭氧胁迫下水稻抽穗期、抽穗后20 d和成熟期基部节间的倒伏指数均无显著变化。进一步研究结果表明,臭氧胁迫下水稻成熟期基部节间单位长度干重和非结构性碳水化合物含量降低引起基部节间充实不良是造成抗折力显著下降的主要原因,而基部节间弯曲力矩下降是稻穗和节间的长度和质量下降共同作用的结果。以上结果表明,未来高浓度臭氧环境条件下粳型水稻的倒伏风险可能不会增加。

This study examined the effects of elevated ozone concentration on lodging resistance of rice by using Free Air Gas Concentration Enrichment（FACE） system which has spatial advantages compared with other gas fumigation experiments conducted in controlled environment.An ozone FACE system was installed in paddy fields in Yangzhou,China.A Japonica rice cultivar Wuyunjing 21 was grown at ambient and elevated ozone concentration（50% above ambient）.Ozone stress had no significant effects on bending moment and breaking-resistance of the basal internodes of Wuyunjing 21 at heading and 20 d after heading（DAH）.However,both bending moment and breaking-resistance of the basal internodes were reduced by elevated ozone at maturity.Elevated ozone concentration had negligible effects on lodging index of basal internodes at heading,20 DAH and maturity.Further studies indicated that the decrease of breaking-resistance strength of basal internodes under elevated ozone concentration was due to poor filling of these internodes as showed by lower dry weight per unit internode length and reduced concentration of carbohydrates,and the decrease of bending moment resulted from lower panicle weight and internode weight as well as shorter internode length.The two traits（breaking-resistance strength and bending moment of basal internodes） resulted in no change of lodging index,which implies that the probability of increase in lodging risk for Japonica rice Wuyunjing 21 is negligible under future high ozone environment.