应用整合分析(meta-analysis)方法定量研究了大气臭氧(O3)浓度增加对小麦光合色素、气体交换和产量形成的影响.通过Web of Sciences和中国期刊全文数据库检索,共收集39篇原始论文.结果表明,大气臭氧浓度增加可导致小麦的产量在当前环境浓度的基础上降低26%,籽粒重、穗粒数和穗数分别降低18%,11%和5%,收获指数减少11%.叶片生理对大气臭氧浓度增加的响应比产量敏感得多,如光饱和光合速率、气孔导度和叶绿素含量分别下降40%,31%和46%.春小麦和冬小麦对臭氧的响应相似.大部分指标显示了小麦叶片生理和产量的降低随着臭氧浓度增加而线性增加的趋势.在小麦灌浆期,臭氧浓度增加引起叶片的光合速率、气孔导度和叶绿素含量降低得最大.大气CO2浓度升高可以明显减轻或抵消大气臭氧浓度增加引起的减产效应.
To assess the responses of the soil microbial community to chronic ozone（O3）, wheat seedlings（Triticum aestivum Linn.） were planted in the field and exposed to elevated O3（e O3）concentration. Three treatments were employed：（1） Control treatment（CK）, AOT40 = 0;（2） O3-1, AOT40 = 1.59 ppm·h;（3） O3-2, AOT40 = 9.17 ppm·h. Soil samples were collected for the assessment of microbial biomass C, community-level physiological profiles（CLPPs）, and phospholipid fatty acids（PLFAs）. EO3 concentration significantly reduced soil microbial carbon and changed microbial CLPPs in rhizosphere soil, but not in non-rhizosphere soil.The results of the PLFAs showed that e O3 concentrations had significant effects on soil community structure in both rhizosphere and non-rhizosphere soils. The relative abundances of fungal and actinomycetous indicator PLFAs decreased in both rhizosphere and non-rhizosphere soils, while those of bacterial PLFAs increased. Thus the results proved that e O3 concentration significantly changed the soil microbial community function and composition, which would influence the soil nutrient supply and carbon dynamics under O3 exposure.
With rapid industrialization and urbanization in the Yangtze Delta, China, the tropospheric ozone concentration has increased to levels that induce crop yield loss. Rice, a widely grown crop in China, was investigated in field-established, open-top chambers. Four treatments were used： charcoal-filtered air （CF）, non-charcoal-filtered air （NF）, and charcoal-filtered air with two levels of additional ozone （O3-1 and O3-2）. The AOT40s （accumulated hourly mean ozone concentration above 40 ppbv） were 0, 0.91, 23.24, and 39.28 ppmv.h for treatment of CE NF, O3-1, and O3-2, respectively. The rice height and biomass were reduced in the elevated ozone concentration. Less organic matter partitioning to roots under the elevated ozone significantly decreased rice root activity. The yield loss was 14.3% and 20.2% under O3-1 and O3-2 exposure, respectively. This was largely caused by a reduction in grain weight per panicle.
CHEN Zhan WANG Xiaoke FENG Zhaozhong ZHENG Feixiang DUAN Xiaonan YANG Wenrui
