Combined computational modeling and experimental analysis integrating chemical and mechanical signals suggests possible mechanism of shoot meristem maintenance
Fig 8
Layer-specific combined chemical and mechanical regulation of cell division plane orientation maintains proper shape, multi-layered structure and spatial distribution of WUS in the SAM.
(A-D) Typical simulation output after 40 hours of growth for all four mechanisms (CAE-E, CAE-M, CED, and combined CAE-M and CED) in wildtype signaling conditions. Cell color highlights distinct patterns of WUS accumulation in the epidermal L1 and L2 cell layers for each mechanism (red = high WUS and blue = low WUS). (E-F) The combined CAE-M and CED mechanism resulted in distributions of (E) mother cell orientations that were similar to experiments and (F) cell aspect ratios that matched experiments. (G) The proportion of periclinal cell divisions in combined CAE-M and CED simulations were found to match experiments. (H) The combined CAE-M and CED mechanism resulted in the smallest amount of deviation from a single-cell layer in the epidermal L1 and L2 cell layers. The combined CAE-M and CED mechanism most closely matched experimentally observed SAM (I) size- the ratio of SAM width to dome height, (J) shape- global curvature of the SAM surface, and (K) WUS distribution in the SAM after 40 hrs of growth. (L) The combined CAE-M and CED mechanism resulted in the correct number of high WUS containing cells in the epidermal L1 cell layer. (E-L) Experimental wildtype (black), CAE-E (blue), CAE-M (gold), CED (green), and combined (red) in all panels. See S3 Appendix for detailed description of all metrics used in this Figure.