observed. The treated seeds had a darker colour shade and got wet
faster in water as compared with the untreated samples (Sera et al.,
2008). A change in the wettability of the seeds as a result of plasma ex-
posure was observed and quantified in our study as well. The same be-
haviour was reported by Bormashenko et al. (2012) who found an
increase ofwater imbibitions of the plasma treatedwheat, bean and len-
til seeds as compared with the control samples. In this case the authors
related the change of wettability of the seeds to oxidation of their sur-
face under plasma treatment, due to a significant increase in the con-
centration of oxygen- and nitrogen-containing groups at the surface of
the treated samples. However, in the case of radish, Kitazaki et al.
(2012) did not detect any oxide formation on the surface of the seeds.
The authors also reported that the morphology of the seed surface
does not change after treatment with RF plasma generated in oxygen.
In this case the growth enhancement mechanism of the plasma treated
samples was attributed only on oxygen radicals generated in the dis-
charge, which induce oxidation reactions in the cell metabolic cycle
(Kitazaki et al., 2012).