Analysis of a mathematical model of shoot gravitropism in Arabidopsis thaliana

Abstract

Plant shoot gravitropism is determined by gravity sensing, curvature sensing (proprioception), and the ability to uphold self-weight. Recently, data- and model-analyses have revealed the detailed morphology of shoot bending, while mechanical mechanism to cause the bending is still unknown. By making a best correspondence between data and model of shoot bending in wild-type and lazy1-like 1(lzy1) mutant Arabidopsis thaliana, we found that both the bending force (derived from the gravi-proprioceptive response) and the stretching force (derived from shoot axial growth) differ significantly between the wild type and mutant. Finally, we interpreted the mechanical forces associated with differential cell growth and provide a plausible mechanical explanation of shoot gravitropism.