Why are the seeds of this species difficult? The seeds have recalcitrant seeds, which have a high critical moisture content and will rapidly lose viability if they are dried. The seeds may also have morphophysiological dormancy.
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This species has Recalcitrant seeds which cannot be dried without causing a decline in viability. Do not place the seeds under sub-zero temperatures as they will suffer from freezing damage due to their high moisture content.
Researchers have found that the embryos can survive desiccation to 14-15% moisture content when removed from the seeds. Cryopreservation of the seeds in liquid nitrogen has also been successful.
The radicle and hypocotyl will only appear after germination outside the seed. For many palm species, germination and development is encouraged by excising the embryo and placing it on a supportive medium.
Some researchers have described the seeds of this species as having Morphophysiological Dormancy (inferred from available information on germination and of characteristics of seeds in this family), where dormancy occurs if the embryo is retained within the seed. The seeds may need to experience several 'seasons' to allow the embryo to grow and develop, before germination will occur. Mimick the seasonal patterns of the species' native habitat to overcome physiological dormancy. Use a moist pre-chill or pre-heat treatment (depending on local climatic conditions), before germinating the seeds on 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.
The fruit (20-30 cm long) is a fibrous drupe, containing a hard-shelled 'nut', and can be ovoid and angular in shape, or spherical. There is a thin epidermis, covering a thick, fibrous mesocarp, within which is a hard, lignified endocarp. Inside the endocarp, at maturity, the white flesh of the endosperm is about 12-15 mm thick, forming a large central cavity.
The pea-sized embryo lies in the flesh under one of the three generative pores at the basal end of the nut. All palm species have rudimentary and poorly developed embryos, with virtually no visible differentiation into identifiable structures.
Accepted name: Cocos nucifera L.
Synonyms: Palma cocos Mill., Calappa nucifera (L.) Kuntze
Common name: coconut
References and Links
- Baskin, C.C. and Baskin J.M. (1998). Seeds: ecology, biogeography, and evolution of dormancy and germination. Academic Press, USA.
- Janick, J. and Paull, R.E. (eds) (2008). The Encyclopedia of Fruit and Nuts. CAB International, UK.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Cocos nucifera.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Cocos nucifera.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Cocos nucifera.
- Tropicos - Missouri Botanical Garden, USA: Cocos nucifera.