H. Ghadiri - Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran.
N. Bagherani Torshiz - Agricultural Research Center, Gorgan, Islamic Republic of Iran.

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 ۲ weeks. At ۵۰C, none of the chemically and mechanically scarified and non scarified seeds germinated. At ۱۵, ۲۵, and ۳۵۰C, mechanical scarification increased seed germination to ۹۴-۹۸%. However, at these temperatures, velocity of germination of mechanically scarified seeds were lowest among all treatments. Chemical scarification also increased germination percentage significantly to ۹۰-۹۵% with ۴۵ min soaking. At ۱۵ and ۲۵۰C, seed germination percentage and velocity of germination increased as the soaking time in sulfuric acid increased from ۵ to ۳۰, ۴۵, or ۶۰ min. However, at ۳۵۰C, there was no difference in germination percentage between soaking times of ۵ and ۶۰ min. It appears that soaking for ۴۵ min provides full germination at ۲۵ and ۳۵۰C.

Licorice dormancy, Weed biology, Weed seed germination