## 4 Discussion
Nevertheless, the body of the accumulated experimental evidence on the persistence of effects in time provides background for the deeper insight on the consequences of stress experienced by the seed. Numerous reports indicate that seed treatment with CP induces multiple adaptive changes observable on later stages of plant vegetation and leading to changes in agronomic plant performance. It has been established that CP induces chemical modifications in seed coats, leading to increased wettability [49] and the seed EPR signal [26; 27; 28]. Rapid changes in the amounts of phytohormones [15; 32; 50], modified DNA methylation in dry seeds [51], changes of protein expression, and enzymatic activities underlying the effects on germination have been demonstrated. Although EMF treatment is less complex and aggressive stressor compared to CP, the observed effects of seed treatments with EMF have many similarities to those induced by CP: EMF increased EPR signal [26], changed the balance of phytohormones [15; 32] in dry seeds, and increased ROS production in germinating seeds [26]. Seed treatments with CP and EMF are further followed by changes in DNA methylation [52], protein expression and numerous enzymatic activities in tissues of growing seedlings [6; 47] including proteins that are important for photosynthetic activity and antioxidant defense. Substantial changes in plant associated microbiome due to sunflower seed treatment with CP have been reported [53]. Much evidence indicates that secondary metabolism is activated in plants growing from the CP- or EMF-treated seeds [12; 16; 34; 54], and that may lead to increased plant fitness and improved growth due to stimulated communication with beneficial microorganisms [32; 48]. It remains to be determined which of these mechanisms are involved in the improvement of agricultural performance of different plants. The obtained results revealed that the effects of pre-sowing treatment of red clover seeds with CP and EMF on germination and seedling growth depend on seed coat color. The extent of variability of seed color in red clover or other plant species exerting seed color polymorphism may depend on the variety (cultivar) or environmental conditions for seed development [29]. Therefore, such dependence may contribute to the variation, masking,or poor reproducibility of the studied CP or EMF treatment effects. It might be reasonable to select seeds by color for certain experimental studies to minimize variation and improve understanding of the molecular mechanisms underlying the effects of treatments. Conceptualization, V.M., I.F., methodology, Z.N., R.Z., V.L. ; investigation, A.I., L.D.-F., R.Z., Z.N. ; data curation, A.I. ; writing--original draft preparation, V.M. ; writing--review and editing, A.I., R.Z., Z.N., V.M., L.D.-F., V.L., I.F. ; visualization, Z.N. ; supervision, V.M., I.F. ; project administration, V.M. All authors have read and agreed to the published version of the manuscript. This research was funded by the Lithuanian Research Council grant nos. S-LB-19-3, S-IJB-19-2, and F19 LITG-008 from the Belarusian Republican Foundation for Fundamental Research. We are grateful for [PERSON] from the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry for providing seeds of red clover cultivar 'Arimaiciai'. The authors declare no conflict of interest.