NO_(2)胁迫下两种鹅耳枥的光合生理特性变化

Photosynthetic physiological characteristics of two kinds of hornbeam under NO_(2) stress

【目的】评价欧洲鹅耳枥和普陀鹅耳枥对NO_(2)胁迫的耐受力,为选择抗大气污染的园林树种提供参考。【方法】以12.0 mg/m^(3)的NO_(2)对欧洲鹅耳枥和普陀鹅耳枥1年生幼苗进行熏气处理,熏气时间分别为胁迫零点(0 h, CK)、1、6、12、24、48、72 h,以及熏气后30 d测定两种鹅耳枥幼苗的光合生理指标和叶绿素荧光特性,分析不同NO_(2)熏气时间与苗木光合生理响应特征的关系,比较两种鹅耳枥对NO_(2)胁迫的适应性。【结果】NO_(2)胁迫后欧洲鹅耳枥具有较高的最大净光合速率(P_(n, max))和暗呼吸速率(R_(d)),较低的光补偿点(LCP)和较高的光饱和点(LSP),表明欧洲鹅耳枥在较宽泛的光照强度下能够正常生长;欧洲鹅耳枥与普陀鹅耳枥的NO_(2)熏气1 h处理组最大PSⅡ光能转换效率(F_(v)/F_(m))值增加,在6 h处理中仅欧洲鹅耳枥的F_(v)/F_(m)值增加,PSⅡ活性增强,用于光合电子传递的能量增多。【结论】推测认为欧洲鹅耳枥能够在NO_(2)胁迫下有序适应外界不良环境,耐受性更强。这对城市道路树种选择与植物配置具有重要意义。

【Objective】This paper is to evaluate the tolerance of Carpinus betulus and Carpinus putoensis to NO_(2) stress, and to provide a reference for the selection of landscape tree species resistant to air pollution.【Method】 The annual seedlings of C. betulus and C. putoensis were fumigated with 12.0 mg/m^(3) NO_(2) for stress zero point(0 h, CK), 1, 6, 12, 24, 48, 72 h, respectively, the photosynthetic physiological indexes and chlorophyll fluorescence characteristics of C. betulus and C. putoensis seedlings were measured 30 days after fumigation. The relationship between different NO_(2) fumigation time and photosynthetic physiological response characteristics was analyzed, and the adaptability of C. betulus and C. putoensis seedlings to NO_(2) stress was compared.【Result】The results showed that after NO_(2) stress, C. betulus had higher P_(n, max) and R_(d), lower light compensation point(LCP) and higher light saturation point(LSP), which indicated that C. betulus could grow normally under a wide range of light intensity. It is increased that the maximum photosynthetical efficiency(F_(v)/F_(m)) of C. betulus and C. putoensis leaf treated by NO_(2) for 1 hour. Only F_(v)/F_(m) value of C. betulus increased, PSⅡ activity and energy for photosynthetic electron transfer increased at 6 h of NO_(2) stress.【Conclusion】It is suggested that C. betulus could adapt to the adverse environment in an orderly manner under NO_(2) stress, with stronger tolerance. The results of this study are of great significance to the selection and allocation of urban road species.