## 4 Conclusions  
We have demonstrated cold plasma treatment could be used as a quick, chemical-free, and effective method to enhance seed germination and seedling growth of mung beans. Both seed germination and radicles were significantly enhanced after plasma treatment. The germination rate increased eleven times after 12 h, while the radicles' length increased around three times after 96 h with optimal plasma treatment parameters. SEM images suggested that the plasmas induce gradual changes in the seed coating and wettability of the seeds. These effects could lead to better water absorption on the surface of treated seeds, and consequently, could enhance the germination rate and promote the growth of the sprout radicles. Through this study, we recommend a plasma energy dosage of 0.08 Wh per seed and NO concentration between 20-95 ppm as the crucial and optimal enhancement conditions. We also show that, for the first time, through delicate extraction, separation, and quantification processes, plasma treatment could induce up to three times higher regulation of natural plant growth hormone GA\({}_{3}\), which could be mainly responsible for phytochemistry pathways of enhancing radicle growth. Finally, further studies are needed to fully understand the influence of cold plasma on the genetic and epigenetic changes of the treated seeds.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app122010308/s1](https://www.mdpi.com/article/10.3390/app122010308/s1)]([https://www.mdpi.com/article/10.3390/app122010308/s1](https://www.mdpi.com/article/10.3390/app122010308/s1)), Figure S1: Characteristics of the plasma jet: (A) voltage-current wavefunction and (B) Lissajous graph of the Ar plasma jet. The dissipated plasma power was estimated using a capacitance C means of 1 nF. Figure S2: (A) Liquid chromatograms of the extracted liquid (blue) vs. (B) the calibration curve of the standard GA\({}_{3}\) (Sigma\(-\)48880) (black). The retention time of GA\({}_{3}\) is from 7 to 8 min, peaking at 7.9. The amount of gibberellic acid (GA\({}_{3}\)) in extracted solution is determined based on the integrated area of the LC spectrum, with averaging of three measurements. Figure S3: Calibration curve derived from the integrated area between 7 to 8 min retention time in the LC spectrum vs. different amounts (0.1; 0.5; 1; 2; 3; 5; 10) ug of the standard GA\({}_{3}\).  
Conceptualization, Q.L.N., N.K.K. and N.T.D.; methodology, L.N.N. and N.T.D.; software, T.Q.X.L., T.T.N. and N.T.D.; validation, T.Q.X.L. and N.T.D.; formal analysis, T.Q.X.L. and N.T.D.; investigation, T.Q.X.L., T.T.N. and N.T.D.; resources, T.Q.X.L. and N.T.D.; data curation, T.Q.X.L. and N.T.D.; writing--original draft preparation, T.Q.X.L. and N.T.D.; writing--review and editing, N.K.K. and N.T.D.; visualization, T.Q.X.L. and N.T.D.; supervision, E.H.C., Q.L.N., N.K.K. and N.T.D.; project administration, N.T.D.; funding acquisition, N.K.K., E.H.C., N.T.D. All authors have read and agreed to the published version of the manuscript.  
This research was funded by IMS, VAST, grant number CS.14/20-21. This research is also supported by NRF Korea (2021R1A6A1A03038785, 2021R1F1A1055694).  
Not applicable.