Abstract text: Plants grow and develop throughout their lives, creating complex morphology through cell expansion and cell division. How plants integrate these processes is a pressing and unanswered question in the field of developmental biology. This project seeks to determine how cell division fits into the landscape of growth regulation, alongside cell wall mechanics and hormonal signalling. This work was done in Arabidopsis thaliana hypocotyls, an organ with few endogenous divisions, allowing for comparison with cell division induction lines. The effects of division on mechanical properties were quantified using Atomic Force Microscopy (AFM) and Automated Confocal Micro Extensometer (ACME). AFM allows for wall-scale measurement of stiffness, while ACME operates at the organ scale. Inducing excess cell divisions in the hypocotyl resulted in altered growth behaviors: increased growth after treatment with brassinosteroid, and decreased growth in shade mimicking conditions. These differences correspond to changes in wall stiffness and appear to be due to changes in wall modification in response to the stimuli, not due to mechanical constraints caused by the simple presence of extra walls. Ongoing work, including a Single-nucleus RNA-seq experiment, is focused on whether this is due to changes in cell identity, hormone activity, or some currently unknown factor.