Abstract: 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 LiDAR 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 threedimensional 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 LiDAR 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.

Key words: paddy soil, rice, Cd, risk assessment.