Influence of temperature and light gradient on leaf arrangement and geometry in cucumber canopies: Structural phenotyping analysis and modelling

Accurate structural phenotyping analysis is essential to understand plant architectural adaptation strategy to environment change. The aim of this study was to analyze leaf arrangement and geometry influenced by azimuthally generated light gradient; and to simulate static and heterogeneous cucumber canopies using regression equations by considering more geometric parameters. Three continuous measurements of structural organ parameters were obtained to fit the organ initiation and expansion curves. Four measurements with three density treatments were obtained to validate model accuracy. To describe leaf distribution and orientation characteristics in more detail, azimuth and elevation models were introduced into canopy structure modelling. Leaf distribution frequency was simulated based on leaf area index and solar elevation angle while leaf elevation was simulated based on leaf azimuth and acropetal phytomer number. This study provides an important basis for structural phenotyping analysis of cucumber canopy, which is essential for more accurate functional-structural modelling in the future. Keywords: Phenotyping, Structure, Heterogeneity, Model calibration, Azimuth, Elevatio