侧柏光合能力与空气负离子浓度的关系

Relationship Between Photosynthetic Capacity and Negative Air Ion of Platycladus orientalis

【目的】通过日光诱导叶绿素荧光(solar induced fluorescence,SIF)指标,探明植被光合能力与空气负离子(negative air ion,NAI)的关系,揭示森林植被对NAI的作用机制。【方法】以北方典型针叶树种侧柏(Platycladus orientalis)为研究对象,基于主要生长季节叶面积指数相对稳定时期同步观测得到的冠层NAI、SIF及光合有效辐射(photosynthetically active radiation,PAR)强度等数据,分析不同时间尺度、日内不同时间段及不同强度PAR条件下NAI与SIF的关系。【结果】冠层NAI与SIF的时间变化趋势一致,SIF能够很好地追踪NAI的季节变化;二者之间存在显著的线性正相关关系,日尺度、小时尺度上二者决定系数R2为分别为0.596、0.474;不同光照强度条件下,冠层NAI与SIF的散点出现明显分层现象,冠层NAI和SIF之间相关性强度在高PAR条件下显著高于低PAR条件,二者的决定系数R2分别为0.483、0.456。【结论】当植被光合作用过程完全激活时,冠层SIF能够更准确地表征NAI的变化过程,对进一步精准评估森林植被对NAI的贡献潜力、丰富森林生态服务功能评估内容具有指导意义。

【Objective】Solar induced fluorescence(SIF)can be regarded as an important indicator that can directly represent the actual vegetation photosynthetic capacity,which can prove the relationship between the photosynthetic capacity and negative air ion(NAI),and thus reveal the mechanism of forest vegetation on NAI.【Method】This study focused on Platycladus orientalis,a typical northern coniferous species,and analyzed the relationship between NAI and SIF under different time scales and solar radiation intensities based on the canopy NAI,SIF and photosynthetically active radiation(PAR)data synchronously observed during the relatively stable period of leaf area index in the main growing season.【Result】The seasonal variation of canopy NAI and SIF was basically the same,and SIF could well track the seasonal variation of NAI;There was a significant linear positive correlation between NAI and SIF,and their determination coefficients(R2)were 0.596 and 0.474 at the daily and hourly scales;The scatter points of NAI and SIF showed obvious stratification under different PAR intensities,and the correlation between NAI and SIF was significantly higher under high PAR than under low PAR,with R2 of 0.483 and 0.456.【Conclusion】When vegetation photosynthesis process was fully activated,canopy SIF can more accurately characterize the NAI process,which can have guiding significance for further accurate evaluation of the contribution potential of forest vegetation to NAI and enrichment of the assessment content of forest ecological services.