Why are the seeds of this species difficult? The seeds may have physiological dormancy, which can be overcome by mimicking the seasonal patterns of the species' native habitat.
Nicotiana tabacum (Image: S. Wood, RBG Kew)
This species has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
Germinate on agar, germination paper (top of paper) or sand at a constant temperature of 20ºC, or using and alternating temperature regime of 30/20ºC (with an 8/16hr photoperiod). It may be necessary to add 101 mg/l potassium nitrate to the medium to encourage germination.
The seeds of this species may have non-deep Physiological Dormancy. If germination is low, this type of seed dormancy can be overcome 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.
(Image: S. Wood, RBG Kew)
The seeds (0.5 mm) are oval to spherical in shape, covered with a fine network of veins. Each seed has 3-5 layers of endosperm and a straight embryo. There are 2000-8000 seeds per capsule.
The seeds are light to dark brown in colour at maturity.
Accepted name: Nicotiana tabacum L.
Synonyms: Nicotiana chinensis Fisch. ex Lehm., Nicotiana mexicana Schltdl., Nicotiana mexicana var. rubriflora Dunal, Nicotiana pilosa Dunal.
Common name: tobacco
References and Links
- Baskin, C.C. and Baskin J.M. (1998). Seeds: ecology, biogeography, and evolution of dormancy and germination. Academic Press, USA.
- Food and Agriculture Organization of the United Nations and International Plant Genetic Resources Institute (1994). Genebank Standards. FAO/IPGRI, Rome, Italy.
- International Seed Testing Association (2010). International Rules for Seed Testing: edition 2010. ISTA, Bassersdorf, Switzerland.
- Purseglove, J.W. (1968). Tropical Crops: dicotyledons. Longman Group Ltd., UK.
- Rao, N.K., Hanson, J., Dulloo, M.E., Ghosh, K., Nowell, D. and Larinde, M. (2006). Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, 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: Nicotiana tabacum.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Nicotiana tabacum.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Nicotiana tabacum.
- Tropicos - Missouri Botanical Garden, USA: Nicotiana tabacum.