Fig. 3: Cell divisions overcome DELLA protection against genotoxic stress.

a Representative confocal images of WT, krp4, gai-1 and gai krp4 root tips treated with 20 μg/ml zeocin for 24 h and stained with PI, which colours cell borders but penetrates dead cells. Seedlings were grown in sucrose-containing medium as indicated in Materials and Methods. The asterisks mark the position of the quiescent center and the arrowheads mark the RAM length. b, c Number of cells in the cortex layer (b) and quantification of cell death (c) in longitudinal sections through the center of the RAM of zeocin-treated seedlings. The dots represent individual values and the horizontal lines represent the mean value per genotype [n = 26, 26, 25, 25 (left to right) in (b); n = 26, 26, 25, 26 (left to right) in (c)]. d Orthogonal views of confocal image stacks of representative WT, smr1, gai-1 and gai-1 smr1 inflorescence apices treated with 100 μg/ml zeocin for 48 h and stained with PI. Dead cells were mainly detected in the L1-L3 cell layers of the SAM (marked with arrows). e Cell death volumes in the SAM region of zeocin-treated inflorescence tips. n = 12, 11, 17, 16 (left to right). Boxplots in raincloud plots show the median (center line), the first and third quartiles (lower and upper bounds, respectively), and the whiskers extend to the minimum and maximum values within the 1.5 times the inter-quartile range (IQR). In (b) and (c), letters denote statistical groups defined by Tukey’s post hoc test following one-way ANOVA [p < 0.05 for (b) and p < 0.01 for (c)]. In (e), p values correspond to one-tailed Mann-Whitney U tests. Scale bars, 50 μm. Source data are provided as a Source Data file.