*3.2. Determination of Rohitukine Uptake by A. thaliana*

After 24 h of treatment, the samples were subjected to HPLC for detection and quantification of rohitukine. In leaf tissues treated with 0.25 mM, 0.5 mM and 1.0 mM rohitukine, 0.009%, 0.013% and 0.014% of rohitukine was found to have accumulated, respectively (Figure 2), whereas in the control samples we did not find a peak corresponding to rohitukine, indicating its absence. A standard sample of 1mg/mL rohitukine was used for the calibration curve. However, in plants that received 1.0 mM of rohitukine treatment, the amount of assimilated rohitukine was of a higher quantity as compared to the lesser amount obtained with the 0.25 mM concentration. Therefore, the uptake and stability of rohitukine was confirmed.

**Figure 2.** Detection and quantification of rohitukine in treated *A. thaliana* samples. (**a**) Structure of rohitukine. (**b**) Calibration curve of standard rohitukine. (**c**) Rohitukine standard, 1 mg/mL. (**d**) *A. thaliana* control peaks showing no traces of rohitukine. (**e**–**g**) Peaks indicating the presence of rohitukine at 0.25 mM, 0.5 mM and 1.0 mM concentrations.
