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.
Lepidium sativum (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, paper toweling folded or rolled in horizontal or vertical position, or between blotters) or sand at 15, 20 or 25ºC, or under an alternating temperature regime of 30/20ºC (with an 8/16hr photoperiod).
The seeds of this species may have non-deep Physiological Dormancy. If germination is 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.
(Image: S. Wood, RBG Kew)
The fruit (5-6 x 3-4 mm) is a silicle: a dry, dehiscent, capsular fruit with a partition bordered by a persistent replum.
See another image of this species at the Digital Seed Atlas of the Netherlands.
Accepted name: Lepidium sativum L.
Synonyms: Crucifera nasturtium E.H.L. Krause, Nasturtium sativum (L.) Moench
Common name: garden cress
References and Links
- Association of Official Seed Analysts (2010). Volume 1: Principles and Procedures. Rules for Testing Seeds. AOSA Inc., Ithaca, USA.
- 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.
- Purseglove, J.W. (1968). Tropical Crops: dicotyledons. Longman Group Ltd., UK.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Lepidium sativum.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Lepidium sativum.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Lepidium sativum.
- Tropicos - Missouri Botanical Garden, USA: Lepidium sativum.