There is disclosed plasmids for the preparation of transgenic plants, as well as the plants, that are modified through the transfer and the expression of genes influencing the sugar metabolism or the sugar partitioning within a plant, which are localised on these plasmids. The transferred genes cause a modified distribution of assimilates in the transgenic plant which result in significant changes in habit, such as size, leaf shape, internode separation and root formation, as well as improvements in yield. Plasmids are also described which enable foreign proteins to be directed into the vacuoles of transgenic plants.