植物叶片润湿性与光谱反射偏振度关系研究

城市绿化植物由于其滞尘能力能够有效改善城市大气环境，滞尘能力的主要影响因素是其表面特性和润湿性。植物叶片表面的润湿性和偏振反射特性都与表面粗糙度相关，因此以粗糙度为结点，探究植物表面润湿性与偏振反射光谱的关系，利用偏振反射特性对植物叶片润湿性进行快速无损监测。以长春市常见的八种绿色植物叶片为研究对象，利用Kruss DSA 100液滴形状分析系统测量其表面接触角，利用多角度光谱测量装置测量其在不同探测天顶角上的偏振反射光谱，探讨了润湿性能在400～1 000 nm波段对植物叶片不同探测天顶角上偏振度的影响。通过相关分析确定八种植物叶片的特征波段，并在特征波段对偏振度随探测天顶角的变化程度与润湿性的关系之间进行定量分析。结果表明，在特征波段(700±10) nm处，偏振度随着探测天顶角的变化程度θ₀与接触角距离100°的偏差值θ具有很强的相关性，可决系数R2为0.82，说明偏振度随探测天顶角的变化程度θ₀可以反映植物叶片的润湿性，可以利用偏振反射特性对植物叶片润湿性进行分析，研究成果将对今后城市绿化物种的选择提供可行性建议。

The Relationship of the Leaf Surface Wettability and Degree of Reflectance Polarization

Urban greening plants can improve the quality of atmospheric environment effectively due to their dust catching property, which mainly influenced by surface characteristics and wettability. We studied the relationship between leaf surface wettability and polarized reflection characteristics because they are both relevant to the surface roughness of leaves. The contact angle of water droplet on leaf surface and the polarized reflectance spectrum from eight major plant species for urban greening in Changchun were measured by Kruss DSA 100 drop shape analysis system and multi-angle spectrum measurement system. We found the characterized band of eight plants through correlation analysis. The influence of wettability on the degree of polarization (DOP) varying with viewing angles was inquired and analyzed quantitatively in the characterized band. The results showed that when the viewing azimuth was fixed at 180°, the DOP spectrum within 400~1 000 nm increased to a maximum, and then began to decline varying with zenith angles from 0° to 60°. The correlation analysis between the deviation from 100° contact angle (θ) and the viewing zenith (θ₀) showed that they were in a linear relationship, with the determination coefficient of 0.82. In this paper, the research achievements will provide feasible suggestions to the options of urban greening plant species in the future.