{Reference Type}: Journal Article {Title}: 3D morphological analysis of Arabidopsis sepals. {Author}: He X;Xu S;Hong L; {Journal}: Methods Cell Biol {Volume}: 160 {Issue}: 0 {Year}: 2020 {Factor}: 1.829 {DOI}: 10.1016/bs.mcb.2020.03.006 {Abstract}: How complicated cell activities produce characteristic tissue and organ morphologies is an important question in plant morphogenesis. To address this question, 3D morphometry of plant organs on multiscales is indispensable. In recent years, advances in confocal microscopy with fluorescent probes that mark the cell wall or plasma membrane enable the visualization of organ morphology with submicron precision. In parallel, new quantitative and correlative imaging pipelines realize 3D image processing on 2D curved surface, facilitating the study of cell and tissue behaviors in plant organogenesis. Here, we describe methods for 3D morphometry of Arabidopsis sepals, focusing on live imaging coupled with MorphoGraphX-based 3D image processing for cellular growth analysis.