In ornamentals, particularly in rose bush, the visual quality of a plant is an important element of its quality. Bud outgrowth, which is at the origin of branching, strongly impacts plant shape and compactness, that are two traits involved in rosebush visual quality (Boumaza et al. 2009).Changes in the environmental conditions, in particular in light intensity, can impact the number of buds that grow out and change bud outgrowth gradient along a stem in various species, including rose (Leduc et al. 2014; Furet et al. 2014). Bud outgrowth is controlled by a network of interacting hormones, the principal ones are auxin, cytokinins and strigolactones, but the role of abscisic acid is also emerging. Sugars are involved in bud outgrowth regulation too and they interact with the hormonal network. A natural hypothesis is that decreasing light intensity may limit bud outgrowth via a shortage in sugars and changes in plant hormonal content. However, the mechanisms by which light intensity affects bud outgrowth, especiallythe respective role of the different hormones and sugars in this regulation, is still poorly understood.The objective of this work was to test if the control of bud outgrowth gradient along the stem by light intensity is mediated by sugars, cytokinins and/or abscisic acid and to assess which of these actors is the main limiting actor. The study was conducted on whole plants and attention was paid to the location of bud outgrowth along the shoot
