Fig. 4
Change of total nitrogen (Nt) and NF-pools in cuttings of Petunia hybrida with graduated nitrogen fertilisation (Nd) to donor plants, dark exposure and AR formation. (Panels a, b, c, d, e): Full cycles and open squared symbols connected with full and intermittent lines show cuttings directly at severance (0 hpe) and after 168 h dark exposure (168 hpe), respectively. (Panels f, g, h, i, j): Full cycles and open squared symbols connected with full and intermittent lines represent cuttings at specific times post insertion for AR formation (0, 6, 24, 72, 168 hpin, corresponding days are shown in the x-axis: 3d, 7d) at 0 hpe and after 168 h dark exposure (168 hpe), respectively. All data are given in μmol N g−1 DM. Multifactorial ANOVA’s revealed significant main and interaction effects for Nd-levels p < 0.01 (Panels a, c, d, f, g, i, j), for dark exposure p < 0.00001 (Panel d), for time post insertion p < 0.0001 (Panel f), for Nd-levels × dark exposure p < 0.05 (Panel b, e), for Nd-levels × time post insertion p = 0.01 (Panel h), for dark exposure × time post insertion p < 0.001 (Panel g, i, j). Vertical bars represent 95 % confidence intervals of mean values. Further details of experiments and statistics are presented in methods and with Additional file 1) Experiments of nitrogen preconditioning of cuttings, Additional file 2) Explanation of experimental designs for statistical analyses and Additional file 3) Supplemental data of figure 4 for Exp. 6: NF-ND (with Panels a, b, c, d, e) and for Exp. 9: NF-NDCR (with Panels f, g, h, i, j), respectively