Figure 1. Basic shoot architecture of a model plant showing location of axillary buds, apex and the distinction between internodes and phytomers.

Figure 2. Arabidopis shoot section showing apical meristem and initiating axillary meristems in the axils of developing leaf primordia.

Figure 3. Classic physiological experiments in apical dominance. Decapitation of the apex leads to a release of axillary buds (left). A lanolin block treated with the auxin, indole-3-acetic acid (IAA), leads to the restoration of bud inhibition (centre). Lanolin + IAA + an inhibitor of polar auxin transport (PAT) leads to a release of axillary meristems (right).

Figure 4. Adult (6-week old) wild-type Arabidopsis (WT) and max1–max4 mutants showing increased branching from the rosette.

Figure 5. Shoot branching in model dicot and monocot plant species. The schematic drawing represents axillary meristem activity during plant development in the described model species. The thick black line represents the main axis which, may be indeterminate in growth (line ends in arrow head) or determinate (no arrow head). The red arrows represent the most basal branches while the blue arrows indicate axillary meristems that arise later in development. Green shapes are leaves and the yellow/white circles are flowers.