African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12235

Full Length Research Paper

Effects of temperature, light conditions and gibberellic acid on the in vitro germination of Protea cynaroides L. embryos

  H. C. Wu1* and E. S. du Toit2  
1Department of Natural Biotechnology, College of Science and Technology, Nanhua University, No. 55, Section 1, Nanhua Rd., Dalin Township, Chiayi 62248, Taiwan (R.O.C.). 2Department of Plant Production and Soil Science, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0002, South Africa.  
Email: [email protected]

  •  Accepted: 01 November 2010
  •  Published: 22 November 2010



Poor and inconsistent germination of Protea cynaroides seeds are often observed in soil. A protocol based on embryo culture was developed for efficient in vitropropagation of P. cynaroides. The effects of temperature, light conditions and gibberellic acid (GA3) on the in vitro germination of P. cynaroides embryos were studied. The results showed that the use of alternating temperatures of 21/12°C (light/dark) significantly improved the germination percentage of the embryos, where 90% of embryos germinated, compared to a maximum of 55% when grown under a constant temperature of 25°C. Mean cotyledon fresh mass of embryos that germinated on media containing gibberellic acid (2.89, 28.89 μM GA3) were significantly higher than those cultured on media without growth regulators. Conversely, root growth was severely inhibited in embryos germinated on media containing gibberellic acid. The in vitro-germinated seedlings were successfully transplanted to a peat/coir/sand mixture in the mist bed.


Key words: Alternating temperature, embryo culture, gibberellic acid, King Protea, Proteaceae.


Abbreviations: GA3, Gibberellic acid; PAR, photosynthetically active radiation.