Methods to break seed dormancy in Cyclocarya paliurus (Batal)Iljinskaja

Abstract

Abstract Cyclocarya paliurus is native to China and is the sole species in its genus. However, the seeds remain deeply dormant for 2 years in their natural environment. We tested different pretreatments of chemical scarification and exogenous application of gibberellic acid (GA 3 ) for efficacy in breaking dormancy and speeding germination. In contrast to scarified seeds, non-scarified seed did not germinate, indicating that C. paliurus seeds have hard, impermeable seed coat dormancy. Exogenous application of GA 3 significantly enhanced germination of scarified seeds. Compared with seeds stratified in sand with water, the germination of seeds stratified in sand moistened with 400 ppm GA 3 for 60 days was significantly increased and germination rate was over 90% after 120 days. Analysis of variance indicated that both GA 3 concentration and stratification medium had significant effects on seed germination and final germination percentage. Germination was higher for longer stratification periods, but no significant difference in germination was observed after 90 days. These results suggested that C. paliurus seeds exhibit both exogenous and endogenous dormancy. A combination of chemical scarification and exogenous application of GA 3 alleviated seed dormancy in a relatively short period of time.