Abstract text: A key question in developmental biology is how genes regulate growth. I am particularly interested in genes that regulate growth repression during leaf morphogenesis. I work on two closely related species within the Brassicaceae family: A. thaliana, which has simple, serrated leaves, and C. hirsuta, which has compound leaves dissected into distinct units called leaflets [Hay and Tsiantis, 2006]. Loss-of-function mutations in the C. hirsuta RCO (REDUCED COMPLEXITY) gene result in simplified leaves, where leaflets are not properly separated [Vlad et al., 2014]. RCO, an HD-ZIP class I transcription factor, is a growth repressor that inhibits both cell expansion and proliferation [Bhatia et al., 2023]. Growth of plant cells is both constrained and facilitated by the cell walls, as it depends on the mechanical balance between cell wall stiffness and extensibility. I test the hypothesis that RCO represses growth through modifying cell wall properties. To this end, I use imaging, genetics and mechanical testing of plant tissues. This work aims to connect genetic regulation of growth with measurable changes in tissue mechanics and provides a framework for further analysis of growth repression.