基于地基激光雷达点云的植被表型特征测量

植物表型是基因型与外界环境共同作用的结果。精确测量植物表型对于植物生理特征与功能性状研究具有重要意义。本研究以加拿大一枝黄花(Solidago canadensis)为对象,对20株植株进行3个月室内培养,各月利用地基激光雷达扫描(terrestrial Li DAR scanning,TLS)系统对实验植株进行多站扫描和点云融合,实现对植株生长过程的连续观测。对于扫描获取的离散点云,利用多端点三维坐标重构法获取植株高度,并基于叶片点云的Delaunay三角网重构叶片表面,获得植株的真实高度、叶面积、叶倾角和方位角等结构参量。对比手动测量结果,发现基于点云重构获得的植株高度与真实植株高度对比,二者间相似性的决定系数(R2)为0.991,叶面积、叶倾角、方位角相似性R2分别为0.989、0.949和0.871;基于TLS点云重构法实现了非破坏性的植物表型测量,能够获得高精度的植物表型特征;多时相扫描能精确监测植物生长过程的表型特征变化。

Plant phenotypic measurement of Solidago canadensis using Terrestrial Li DAR Scanning

Plant phenotype as a function of the interactions between its genotype and environment reflects plant adaptive strategies in the environment. Precise measurements of plant phenotypic traits are the basis for accurate determination of plant morphology,structure,growth and development. In this study,20 individuals of Solidago canadensis were cultivated for three months,and they were scanned in situ once a month at nine different scanning stations using Terrestrial Li DAR Scanning(TLS) system,which presented a repeated measurement of three-dimensional point cloud data during plant growth. Plant height was obtained by constructing normal vectors with three-dimensional coordinates of multiple endpoints. The leaves were reconstructed by threedimensional point cloud data. Based on the Delaunay triangulation method,leaf point cloud was encapsulated to pursue the data of leaf area,leaf inclination angle and azimuth angle. In addition,we measured these traits with traditionally hand-based(THB) methods,i.e. using ruler for plant height,leaf area meter for leaf area,and compass and protractor for leaf inclination angle and leaf azimuthal angle. By comparing the results obtained with TLS and THB methods,we found that the similarity in trait values for plant height,leaf area,leaf inclination angle and leaf azimuthal angle were 0.991,0.989,0.949 and 0.871,respectively. Therefore,our results suggest that the Li DAR scanning method can provide accurate and multi-type phenotypic traits of plants in a fast scanning event. As a non-destructive method,it is suitable for long-term repeated observations of plant phenotypic traits.