Effects of Cold Plasma on Old Seed Germination Characteristics of Codonopsis pilosula

Abstract. Cold plasma seed processing is a kind of science application that taking modern physical technology in agriculture. This paper has described works that processing old Codonopsis pilosula seeds by cold plasma which was excited by helium gas. The experiment was under the settled condition that increasing pressure from 60 Pa air pressure to 130~160 Pa by helium gas and processing 20 s. The consequence shows that promotion effect was widely found in germination rate in different processing treatment intensity. There were two peaks about germination rate in 30 W and 300~450 W which approach 75% and 80% respectively (increasing 15% and 20% approximately). When the treatment intensity was lower than 270 W, the germination energy experienced a certain extent of inhibiting effect. However, between 360 W to 420 W, the germination energy increased to 31% which was higher 8.1% than control group. The research indicates that low-temperature plasma seed treatment technology could promote the germination rate of old Codonopsis pilosula seeds in different extent while low treatment intensity would restrain germination energy and high intensity could accelerate it.