Effects of dormancy-breaking treatments on seed germination of Koelreuteria paniculata and Mahonia aquifolium

The present paper examines the germination requirements of the seeds of two woody species (Koelreuteria paniculata and Mahonia aquifolium).Koelreuteria paniculata seeds were subjected to a combination of acid scarification, gibberellic acid (GA 3 ) and cold stratification treatments.Un-scarified seeds, which were only cold stratified (up to 3 months) as well as the seeds which were only acid-scarified (up to 60 minutes) exhibited low germination percentages.The combination of sulphuric acid scarification and cold stratification treatments significantly improved germination.In acid-scarified seeds, GA 3 application improved germination, but did not fully replace the cold stratification period required to break seed dormancy.Mahonia aquifolium seeds were subjected to a combination of GA 3 and cold stratification treatments.Notably, prolonged cold stratification is essential for the germination of M. aquifolium seeds since seeds stratified for 1 or even 2 months did not germinate.In almost all cases, the percentage of M. aquifolium seeds germinated was higher with GA 3 treatment applied prior to cold stratification than with cold stratification only.