Panicum laetum

Why are the seeds of this species difficult? Some species of the Poaceae family can produce a high proportion of empty seeds, which collectors and curators must take account of. The seeds may have physiological dormancy.

Panicum laetum (Image: S. Wood, RBG Kew)

Seed Storage

This species most probably has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.

Germination Requirements

Remove the seed covering structures before placing the seeds under germination conditions. Germinate on agar, germination paper or sand, under an alternating temperature regime of 35/20ºC (with an 8/16hr photoperiod). Perform a cut-test on any seeds that have not germinated, to check for empty seeds. All empty seeds are non-viable in germination tests.

The seeds of this species may be Physiologically Dormant (based on other species in the same genus). 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.

Seed Morphology

Panicum laetum
(Image: S. Wood, RBG Kew)

The occurrence of empty seeds is common in wild-collected accessions of some Poaceae species. Empty seeds may have a normal seed coat but an absent or under-developed embryo, or limited storage tissue.

Taxonomy

Family: POACEAE

Genus: Panicum

Species: laetum

Accepted name: Panicum laetum Kunth

Synonyms: Panicum sociale Stapf - non Napper, Panicum albidulum Steud.

Common name:

References and Links

Black, M., Bewley, J.D. and Halmer, P. (2006). The Encyclopaedia of Seeds: science, technology and uses. CAB International, UK.
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: Panicum laetum.
PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Panicum laetum.
SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Panicum laetum.
Tropicos - Missouri Botanical Garden, USA: Panicum laetum.