Using low-pressure plasma for Carthamus tinctorium L. seed surface modification

Low-pressure RF argon gas discharge was used for surface modification of Safflower (Carthamus tinctorium L. semen) to increase the germination rate and activity and reduce the germination time. The results showed that plasma-treated C tinctorium L. semen has 50% higher germination rate, 100% increase in the activity and 24h reduction in germination time relativeto untreated. The effect of two different pressure plasma treatments at constant power and exposure time were also investigated. The result showed that the low-pressure plasma treatment was a more effective way to increase the germination rate at a smaller plasma treatment time. Using scanning electron microscope (SEM), the surface structure of plasma-treated and untreated C tinctorium L. semen has been characterised. The SEM observations of Carthamii pericarpium and Hilum showed a change in the surface structure after plasma treatment. The physical structure of Carthamii pericarpium after plasma treatment looks softer relative to untreated. The Hilum of untreated C. tinctorium L. semen showed a very nice structure and boundary layer whereas after plasma treatment the structure was modified. (c) 2005 Elsevier Ltd. All rights reserved.