Effects of Scarification and Temperature on Germination of Licorice (Glycyrrhiza glabra L.) Seeds

Laboratory experiments were performed to determine the effect of various scarification
treatments at four temperature regimes on germination of licorice seeds . A randomized
complete block design with four replications was used. Germination counts were made
every day for 2 weeks. At 50C, none of the chemically and mechanically scarified and non
scarified seeds germinated. At 15, 25, and 350C, mechanical scarification increased seed
germination to 94-98%. However, at these temperatures, velocity of germination of mechanically
scarified seeds were lowest among all treatments. Chemical scarification also
increased germination percentage significantly to 90-95% with 45 min soaking. At 15 and
250C, seed germination percentage and velocity of germination increased as the soaking
time in sulfuric acid increased from 5 to 30, 45, or 60 min. However, at 350C, there was no
difference in germination percentage between soaking times of 5 and 60 min. It appears
that soaking for 45 min provides full germination at 25 and 350C.