Changes in Growth and Production of Non-Psychotropic Cannabinoids Induced by Pre-Sowing Treatment of Hemp Seeds with Cold Plasma, Vacuum and Electromagnetic Field

Abstract

In this study, the effects of seed treatments with different stressors, such as cold plasma (CP), a vacuum and an electromagnetic field (EMF), on the in vitro germination of industrial hemp cv. Futura 75 were compared with the effects on germination in the field, plant growth, and the amount of major cannabinoids in the leaves and inflorescences of female plants. CP and EMF (but not vacuum) treatments improved in vitro seed germination, but had no impact on germination in the field. EMF treatment increased the weight of the above-ground part of male and female plants grown for 4 months by 65–70% and the number of female inflorescences by 70%. CP stimulated the growth of male plants (weight increased 1.4 times) but reduced the growth of female plants. Vacuum treatment did not induce changes in the growth of female and male plants. Vacuum and EMF treatments did not change the amount of cannabidiolic acid (CBDA), but CP decreased the CBDA content in hemp leaves by 41%. Vacuum treatment increased the amount of CBDA in female plant inflorescences by 26%. Thus, hemp seed treatment with EMF has a potential application for increasing the biomass of female plants. CP treatment can be used to increase male plant production while vacuum treatment can stimulate CBD production.

Changes in Agricultural Performance of Common Buckwheat Induced by Seed Treatment with Cold Plasma and Electromagnetic Field

“…At this time point, seed treatment led to an improvement in the indices of photosynthetic efficiency in leaves of 'VB Nojai', but not 'VB Vokiai' seedlings. This result indicates that stimulation of plant growth by seed treatments is related to the activation of photosynthetic processes, which also confirms the results obtained in sunflowers [35,36]. Stimulation of the net rate of photosynthesis in seedlings growing from CP treated seeds has been demonstrated directly in wheat [47].…”

“…We showed that the effects of seed treatments on buckwheat growth persist for the entire vegetation season, and that the effects on biomass production and seed harvest are considerably larger in comparison to the effects on seed germination. We have previously demonstrated that the effects of seed treatments on germination in vitro are different from those in substrate for Norway spruce [33] and sunflower [34,35], as well as on seedling emergence in the field for industrial hemp [36]. In the case of buckwheat, little to no effect on germination was observed in vitro, while no effect or a moderate negative effect (11-20%) was found on seedling emergence in field conditions.…”

“…Substantial changes in plant associated microbiome due to sunflower seed treatment with CP have been reported [62]. Numerous findings indicate that secondary metabolism is activated in plants growing from the CP-or EMF-treated seeds [30,36,45,63], and that may lead to increased plant fitness and improved growth due to stimulated communication with beneficial microorganisms [59,64]. It remains to be determined which of these mechanisms are involved in the improvement of agricultural performance of common buckwheat and other plants.…”

“…The equipment and the conditions used for seed treatment have been described earlier [32,36] in more detail. Seeds were treated with radiofrequency (RF) EMF using RF generator frequency 5.28 MHz.…”

“…Germination tests in vitro were performed 4 days after CP treatment as described earlier [30,32,33,36], using three replicates (50 seeds each). The germination results of each experimental replicate were analyzed using the Richards' function [37] for the analysis of germinating seed population [38].…”