Allometry and Plasticity of Meristem Allocation throughout Development in Arabidopsis thaliana

1 The three principal fates of axillary meristems in flowering plants are branching or vegetative growth, reproduction, and inactivity. We examined the relationship between allocation to each of these fates and plant size in five genotypes of Arabidopsis thaliana. Nutrient availability was used to obtain a range of plant size. 2 Allocation to each meristem fate was recorded at weekly intervals throughout development and at final developmental stage. 3 There were significant allometric relationships between meristem allocation and plant size for each meristem fate throughout development in each genotype. Allometry and plasticity tended to be strongest early in development. In addition, although there were differences in allometry between genotypes, meristem allocation through development was generally consistent across genotypes. 4 We interpret the results of this study as an adaptive response to nutrient availability. Increased allocation to growth meristems in high nutrient treatments early in development should maximize both size and the total number of meristems that can be committed to reproduction later in development. This suggests that the pattern of meristem allocation is a component of an adaptive strategy through development in Arabidopsis thaliana.