Fig. 3. KRP2 mediates DELLA control of meristem size and bud production but not stem elongation.

(a) Representative images of L-er (wild-type), krp2-3, gai and gai krp2-3 plants with 3-5 mature flowers. (b) Boxplots of plant height at the stage shown in (a) (7 plants per genotype). (c) Boxplot of SAM areas measured as in Fig. 1 for wild type, krp2-3, gai and gai krp2-3 (10, 8, 10 and 10 plants, respectively). (d-g) Orthogonal views of confocal image stacks of representative inflorescence apices stained with mPs-PI; within the meristem, defined using landmarks placed on bud boundaries, the RZ (red) was selected as a region within 90 µm of a plane crossing the meristem summit and normal to the main SAM axis, with consistently thicker walls (based on mPS-PI signal) and vertically oriented divisions (based on the orientation of the thinnest wall); the tunica region (blue) was selected within 15 µm of the meristem surface and 30 µm from the plane crossing the summit (details in Supplementary Information). (h) Boxplots of cell numbers in the tunica (blue) and RZ (red) regions for different genotypes (11 plants for krp2-3, 10 for other genotypes). (i) Cumulative number of mature flowers in the main inflorescence of wild-type, krp2-3, gai, gai krp2-3 and global della plants (average and SD for 10 plants per genotype); day 0 was when floral buds were first visible by eye. Bars: 1 cm (a), 50 µm (d-g); p-values in b, c, h are for equality of means (Student’s t-test).