Flowering Response to Transplanting and Rooting Manipulations in Arabidopsis thaliana (Brassicaceae)

In Arabidopsis thaliana (Brassicaceae), time to flowering was followed by counting the number of rosette leaves produced before bolting in both wildtype and late-flowering mutant luminidependens-2 plants. Crowding and nutrient and water deprivation decreased the number of rosette leaves produced before bolting. Transplanting whole seedlings, rooting seedlings, rooting shoot tips, and growing plants from seed in enclosed containers also decreased the rosette-leaf number before flowering, with the most drastic reduction being observed for plants grown from seed in enclosed containers. Wildtype strains went from ca. 20 to five rosette leaves, while luminidependens-2 went from ca. 40 to five. In contrast, the number of rosette leaves was not affected when intact seedlings were transplanted to soil or peat pellets in open pots or when leaves were removed. These results indicate that the number of nodes produced before flowering in Arabidopsis is an easily perturbed trait. This documentation of stress-induced node number variation, especially in those transplanting techniques typically used to assay floral determination, indicates that floral developmental states will not be easily assessed in Arabidopsis.