Germination response of Zanthoxylum capense (small knobwood) seeds to different pre-treatment protocols

  • O Bodede
  • S Shaik
  • R Moodley
Keywords: Dormancy, scarification, germination, chilling, hot water treatment.


Background: Zanthoxylum capense is an important medicinal species in South Africa. It is propagated  by seeds which are dispersed by different animals but the seeds rarely germinate even under favourable  germination conditions which could be the result of dormancy. In addition, the species is currently listed as threatened in the Red List of South African Plants; therefore, it is of importance to find ways of  promoting its propagation.
Materials and Methods: The germination of Z. capense seeds in response to different scarification and  stratification pre-sowing treatments was studied. Seed stratification included chilling at 4oC. Seed  scarification was performed mechanically, using hot and cold water, and using hydrochloric acid and sulphuric acid.
Results: The highest final germination percentage (FGP) (71.1%) was obtained from seeds soaked in hot  water for 15 minutes and grown in dark conditions. The 30 days chilling treatment also gave a good  response (57.8%) when grown under light or dark conditions. Other FGPs of note included seeds soaked  with 500 ppm gibberellic acid (GA3) (60%, light; 44.4%, dark) and 1000 ppm GA3 (46.7%, light; 48.9%, dark) and soaking in H2SO4 for 5 minutes (42.2%, dark). Overall, the seeds sown under dark conditions produced better FGPs than those sown in light.
Conclusion: These results reveal that Z. capense seeds display combinational dormancy that imposed  physically by the seed coat and that imposed physiologically by the embryo. These dormancy traits can be easily overcome by either chilling or soaking in hot water or GA3.

Key words: Dormancy, scarification, germination, chilling, hot water treatment.


Journal Identifiers

eISSN: 0189-6016