南昌近地层臭氧分布及其对敏感木本植物叶片的伤害

近年来,由于光化学反应引起的臭氧(O3)前体物增加,使全球植物受近地层O3胁迫的程度越来越严重。在东欧、西欧以及美国,O3污染被认为是造成大片森林植被衰退和枯死的主要原因。本研究通过对亚热带城市南昌城区至郊区森林植被的实地调查,结合2014年4-8月南昌近地层O3浓度实时监测数据,并参考O3伤害评估手册中的鉴别方法和标准,分析了南昌市近地层O3时空分布特征及其对木本植物叶片的伤害情况。结果显示:近郊区的O3浓度显著高于远郊区和城区;6月份的O3平均浓度最高,其累计剂量(AOT40)达35.5 mg·m-3·h,远远超过了植物受O3伤害的临界值(19.6 mg·m-3·h),即已经对植物造成了危害;在南昌市近郊区和远郊区,共有16种植物表现出典型的O3伤害症状,如叶缘干枯,叶片表面出现有色斑点、斑块、条带状变色等,其中东京樱花(Cerasus yedoensis(Mats.)Yüet Li)、紫楠(Phoebe sheareri(Hemsl.)Gamble)、闽楠(P.bournei(Hemsl.)Yang)、山鸡椒(Litsea cubeba(Lour.)Pers.)可作为南昌地区的O3污染指示物种。

Tropospheric Ozone Distribution and Injury on Leaves of Sensitive Woody Plants in Nanchang City,China

In recent years, the increase in ozone precursors caused by photochemical reactions has increased plant stress from tropospheric ozone. Ozone pollution is considered the primary cause of forest degradation and tree dieback in Eastern and Western Europe and the United States. Based on urban to exurban investigation in Nanchang city, representing subtropical urban areas in China, and tropospheric ozone concentration monitoring data of Nanchang from April to August 2014, the temporal and spatial distribution characteristics and the effects of tropospheric ozone on plants were studied via ozone injury assessment. The ozone concentration of suburban regions was significantly higher than that of the urban and exurban regions. The highest average concentration of ozone occurred in June, with the AOT40 value reaching 35.5 mg·m^-3·h, well over the 19.6 mg·m^-3·h threshold considered to exert negative influences on the growth of wild plants. Sixteen plant species exhibited typical injury symptoms caused by ozone pollution in suburban and exurban regions, and included exsiccation of the leaf margin, colored spots, patches, and strip coloring between the veins of the upper leaf surface. Furthermore, Cerasus yedoensis (Mats.) Yü et Li, Phoebe sheareri (Hemsl.) Gamble, P. bournei, and Litsea cubeba)(Lour.) Pers. might work as bio-indicators of ozone pollution in Nanchang.