Effect of SA on growth and development of Arabidopsis. A, Root phenotype of seedlings (12 DAG) grown on 0.5 × MS-medium supplemented with SA (n > 20; scale bar: 1 cm). B, Number of adventitious roots of seedlings 12 DAG grown on 0.5 × MS-medium supplemented with SA. Plants were germinated (after a short light-pulse of 4 h) for 7 d in darkness and subsequently transferred to light for 5 d to stimulate adventitious rooting. Adventitious root numbers (percentages) are represented in grayscale (n > 30). C, Lateral root density of seedlings (12 DAG) grown on 0.5 × MS-medium supplemented with SA (n > 15). Error bars represent sds. No significant differences were obtained between the mock-treated control sample and SA-treated samples as determined by Dunnett’s test P values > 0.05. D, SA dose response curve for primary root growth (sigmoidal-logistic, four parameters; n > 20). Error bars represent sds.