## 4 Discussion
The obtained results are in line with recently reported observations that radial (_R. sativus_) seeds of different coat colors show different responses to atmospheric DBD plasma treatment [27; 28]. In this study, we used low-pressure RF plasma. This study also confirmed the finding of [28], i.e., that the content of phytohormones in seeds controlling the germination is dependent on the seed color. We found significant differences in the content of phytohormones in control seeds of red clover of three selected colors (yellow, brown, and dark purple, excluding intermediate versions) (Table 2). However, the effects of CP and EMF treatments on germination (Table 1) did not correlate with the observed shift in the balance of phytohormones. The alleviation of physiological dormancy and stimulation of germination are associated with an increase in the ratio GA/ABA [40; 46], but CP-induced decrease in the amount of ABA was observed in dark purple seeds only, whereas ABA was increased after CP treatment in yellow or brown (CP5 group) seeds (Table 2). The amount of GA7 was below the detectable level in the control yellow seeds and CP increased GA7 amounts. Possibly, other biologically important gibberellins (detectable by MS method only) may be characteristic of the yellow seeds of the 'Arimaiciai' cultivar. The content of GA7 in brown control seeds was reduced by CP treatments; CP5 increased GA7 only in dark purple seeds. Effects of EMF treatments on ABA and GA7 content were also dependent on seed color, but irrespective of seed color, EMF induced a strong decrease in Z and SA content. Although physical dormancy is typical for legumes, including red clover, we have reported previously that CP and EMF treatments induced GA/ABA increase in dry seedsof the red clover cultivar 'Sadunai' [32]. However, the amount of ABA in the control seeds of 'Sadunai' [32] was from 6.6 to 20-fold larger compared to brown and yellow 'Arimaicai' seeds, respectively (Table 2); thus, control seeds used for the experiment in this study did not exert signs of physiological dormancy. Therefore, treatments did not induce changes in the balance of phytohormones characteristic for the break in physiological dormancy [40; 46]. In such situations, seed treatments may act by changing the properties of the seed coat. Nevertheless, a higher amount of ABA in dark purple seeds compared to yellow ones may be explained by the ability of proanthocyanidins to promote ABA synthesis [47]. The effects of seed treatments on early seedling growth were dependent on seed color but did not always correlate with the effect of stressors on seed germination. Treatments increased the length of 'Arimaicai' seedlings growing from yellow and dark purple seeds, but the weight of seedlings from brown seeds. In seedlings grown for 5 weeks (Figure 4), treatments induced changes only in the morphometric parameters of the roots but not in the above-ground part. In the control group, roots of seedlings from dark-purple seeds were longer but had smaller weight compared to yellow seed seedlings, but CP treatments increased their weight. The largest coat color-dependent difference was observed in the number of root nodules, which was particularly low in the roots of dark purple seed seedlings; however, both CP and EMF treatment effectively (13-27 times) increased their nodulation activity. As a result, the seed color-dependent difference in treated seedlings was much less (EMF15 group), or nodulation in dark purple seed seedlings even became higher (CP7 group) compared to the yellow seed seedlings. Thus, the results of this study are in line with previously reported findings that CP treatments activate root nodulation in soybean [48] and red clover [32]. In addition, the dependence of the effect on seed coat color was demonstrated. The molecular mechanisms underlying the effects of seed treatment with CP are currently under intensive research (see the most recent reviews [1; 2; 3; 42]); however, numerous key questions still remain to be established.