In this paper, we will present results of plasma treatments of meristematic cells of Daucus carota. Plasma needle was used as an atmospheric pressure/gas composition source of non-equilibrium plasma in all treatments. Activity of antioxidant enzymes superoxide dismutase and catalase was measured immediately after plasma treatment and after two weeks following the treatment. Superoxide dismutase activity was increased in samples immediately after the plasma treatment. On the other hand, catalase activity was much higher in treated samples when measured two weeks after plasma treatment. These results show that there is a direct proof of the triggering of signal transduction in the cells by two reactive oxygen species H2O2 and O2−, causing enzyme activity and short and long term effects even during the growth of calli, where the information is passed to newborn cells over the period of two weeks.

No abstract

The presented study aimed to investigate the elicitation possibility for the production of main secondary metabolites in Nepeta cataria L. and N. pannonica L. plants, by exposing them to synthetic compounds belonging to tetraoxanes and thiophenes group. The effect of DO63 (1,2,4,5-tetraoxane) and DOVF15 (2,5-diphenylthiophene) on the production of cis-trans-nepetalactone (NL) and rosmarinic acid (RA) in two Nepeta species, was investigated in shoots grown on the culture medium with the addition of synthetic compounds in the concentrations ranging from 0.1 to 2 mg L-1. The content of targeted metabolites in tested in vitro shoots depended on the type and concentration of applied synthetic compounds. Application of DO63 in the concentration range 0.1-1 mg L-1 affected only NL production in both Nepeta species resulting in its increased content, while production of RA was not influenced in the treated shoots. Addition of DOVF15 caused decreased RA content in N. pannonica shoots and an increase in N. cataria shoots, whereas NL production was not affected. The presented results reveal the possibility of DO63 and DOVF15 application for the elicitation of the main secondary metabolites production in species from the genus Nepeta.