Why are the seeds of this species difficult? The seeds of this species could have physical or physiological dormancy. Physical dormancy can be overcome by scarifying the seed coat to allow water uptake and encourage germination. Mimicking the seasonal patterns of the species' native habitat can overcome physiological dormancy.
Pappea capensis (Image: S. Wood, RBG Kew)
This species has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
To overcome Physical Dormancy, chip the seed coat with a scalpel before placing the seeds under germination conditions. Germinate on agar, germination paper or sand at 25ºC.
The seeds of this species may also be Physiologically Dormant (based on members of the same family). If germination is still low, overcome dormancy by mimicking the seasonal patterns of the species' native habitat. Use a moist pre-chill or pre-heat treatment (depending on local climatic conditions) or a dry after-ripening treatment, before germinating the seeds on agar, germination paper or sand at their optimum temperature. If this does not work, you can perform delicate surgery to enable the embryo to grow. Excise the tissue near the root tip.
Pappea capensis section
(Image: S. Wood, RBG Kew)
Accepted name: Pappea capensis Eckl. & Zeyh.
Synonyms: Pappea fulva Conrath, Pappea ugandensis Baker f., Pappea capensis var. radlkoferi (Schweinf.) Schinz, Pappea radlkoferi Schweinf., Pappea radlkoferi var. angolensis Schltr., Sapindus pappea Sond.
References and Links
- Food and Agriculture Organization of the United Nations and International Plant Genetic Resources Institute (1994). Genebank Standards. FAO/IPGRI, Rome, Italy.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Pappea capensis.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Pappea capensis.
- Tropicos - Missouri Botanical Garden, USA: Pappea capensis.