(a) 3D reconstructions from confocal stacks of shoot apices stained by the modified pseudo-Schiff propidium iodide (mPS-PI) method; rgaΔ17 is short for RGAp:GFP-rgaΔ17 and global della is the quintuple mutant gai-t6, rga-t2, rgl1-1, rgl2-1, and rgl3-411; numbers indicate floral buds emerging from the SAM, in order of age (youngest marked 1). (b) Boxplots showing projected SAM area in genetic backgrounds with altered DELLA function (10 apices each for wt, gai and ga4-1; 8 each for rgaΔ17 and global della); p-values are for equality of means (Student’s t-test). (c) Illustration of how projected SAM areas were measured; in this vertical projection of a wt inflorescence apex, the measured region in red corresponds to the meristem surface determined on a 3D image using landmarks placed on bud boundaries (details in Materials and Methods). Bars: 50 µm.