Seed characterization for propagation and conservation of Oxera pulchella subsp grandiflora (dubard) de kok, a new caledonian ornamental endemic

2016

Article référencé dans le Web of Science WOS:000392367500004

Zongo C., Sabourin M., Demaret L., Gateble G., Fogliani B., Marmey Philippe

Propagation of Ornamental Plants, 2016, 16 (4), p. 137-145 ISSN 1311-9109

The Royal Creeper, Oxera pulchella subsp. grandiflora (Dubard) de Kok (Lamiaceae) is a New Caledonian threatened endemic taxon with high ornamental potential. Propagation by cuttings has till now been the main propagation method for ornamental uses. A characterization of the seed biology is required in order to promote a better development of O. pulchella subsp. grandifiora ornamental potential, through maintaining its genetic diversity and its conservation. A seed analysis was conducted to define seed structure, germination conditions, dormancy, and desiccation tolerance. Seeds were shown to be of exalbuminous type with a permeable endocarp. Seeds displayed a non-deep physiological dormancy. When desiccated by equilibration in nine atmospheres with controlled relative humidity, seeds desiccated to lower water content (2.8 +/- 0.5% of fresh weight) displayed a germination rate of 63 +/- 13% compared to non-desiccated control, indicating that Oxera pulchella subsp. grandiflora seeds were desiccation-tolerant. Protocols combining seed desiccation and low temperatures storage revealed that seeds desiccated in an atmosphere with a relative humidity of 45% and conserved at 4 degrees C were viable after one-year period storage, with a germination rate of 50%. Our study shows that a characterization of physiological traits of seeds, such as germination, dormancy and desiccation tolerance, may lead to favoring the seed as a means of propagation for ornamental uses and conservation.

Sciences du monde végétal [076]

NOUVELLE CALEDONIE

Fonds IRD

PAR00015592