## 4 Discussion  
Pre-sowing seed treatments with various dormancy-breaking agents are traditionally applied to stimulate crop germination and to increase the uniformity of germination [3, 4]. In addition to changes in germination (tested in vitro under laboratory conditions), CP and EMF treatments can decrease seed microbial contamination and exert positive effects on early seedling growth. However, rather moderate effects (5-20%) on early growth have been achieved for the majority of annual crops [5, 6, 7, 8, 9]. The application of such innovations in agriculture requires knowledge on how plants respond to such treatments over a longer time scale and under more natural conditions. It is important to estimate if the effects observed on seed germination and growth in the laboratory are followed by changes in plant behavior throughout the entire vegetation cycle while cultivated in the field. A small number of long-term studies on the effects of CP [10, 29, 30, 31, 32] and EMFs [10, 33, 34, 35, 36] have been performed, and the results show that the effects of seed treatments on crop growth are retained for the whole vegetation period in most cases. However, for industrial hemp, studies have been limited on the effects of CP on germination and early seedling growth. It has been shown that gliding arc plasma treatment can increase the growth of seedlings (estimated up to 5 days of cultivation) in both cv. Finola and cv. Bialobrzeskie hemp, while seed treatment with CP, generated by a downstream microwave device, inhibited seedling growth [14, 15]. It has been reported recently [16] that hemp seed treatment with DBD (dielectric barrier discharge) plasma stimulated 8-day-old seedling growth and enhanced the transcription rates of the transcription factor WRKY1 and four key genes involved in the biosynthesis of cannabinoids in the leaves of 30-day-old seedlings. The expression of olivetolic acid cyclase was increased 42 times, olivetol synthase 19 times, cannabidiolic acid synthase 12.4 times, and \(\Delta\)9-tetrahydrocannabinolic acid synthase 25.6 times. The latter finding implied that hemp seed treatment with CP may have a strong effect on the biosynthesis of hemp's secondary metabolites, in line with findings reported on other plants [10, 21, 22, 23]. However, the amount of cannabinoids was not measured in this study [13]. In this study, the effects of seed treatments with three different stressors (CP, a vacuum, and EMFs) on the in vitro germination of industrial hemp cv. Futura 75 were compared, both with the effects on germination in field conditions and on plant growth for the entire vegetation season (4 months). In addition, the amounts of CBDA and CBD, the major cannabinoids biosynthesis by industrial hemp cv. Futura 75 [37, 38], in the leaves and infloresences of female plants were estimated in the control and treated groups. The obtained results showed that both the CP and EMF treatments increased the maximal germination percentage of hemp seeds, but only the CP treatment increased the rate of germination in vitro under laboratory conditions (Table 1). However, maximal germination in the field was not affected by seed treatments. Thus, the results obtained in the laboratory had low prognostic value concerning the effects on germination in the field. This finding is in line with the observations reported earlier [39, 32], suggesting that the effects of seed treatments on germination in vitro and under other conditions (e.g., in the substrate) are different. Treatment with CP5 significantly improved seed germination kinetics, but had an adverse effect on female plant height, antioxidant leaf activity, and cannabinoid content in the leaves and infloresences. A decrease in CBD and CBDA content seems to be in apparent contradiction with the reported CP-induced increase in the expression of genes involved in the biosynthesis of cannabinoids [13].