title: Annual dormancy cycles in buried seeds of shrub species: germination ecology of Sideritis serrata (Labiatae).
abstract: The germination ecology of Sideritis serrata was investigated in order to improve ex-situ propagation techniques and management of their habitat. Specifically, we analysed: (i) influence of temperature, light conditions and seed age on germination patterns; (ii) phenology of germination; (iii) germinative response of buried seeds to seasonal temperature changes; (iv) temperature requirements for induction and breaking of secondary dormancy; (v) ability to form persistent soil seed banks; and (vi) seed bank dynamics. Freshly matured seeds showed conditional physiological dormancy, germinating at low and cool temperatures but not at high ones (28/14 and 32/18 °C). Germination ability increased with time of dry storage, suggesting the existence of non-deep physiological dormancy. Under unheated shade-house conditions, germination was concentrated in the first autumn. S. serrata seeds buried and exposed to natural seasonal temperature variations in the shade-house, exhibited an annual conditional dormancy/non-dormancy cycle, coming out of conditional dormancy in summer and re-entering it in winter. Non-dormant seeds were clearly induced into dormancy when stratified at 5 or 15/4 °C for 8 weeks. Dormant seeds, stratified at 28/14 or 32/18 °C for 16 weeks, became non-dormant if they were subsequently incubated over a temperature range from 15/4 to 32/18 °C. S. serrata is able to form small persistent soil seed banks. The maximum seed life span in the soil was 4 years, decreasing with burial depth. This is the second report of an annual conditional dormancy/non-dormancy cycle in seeds of shrub species.
authors.affiliation: Higher Technical School of Agronomy and Forestry Engineering, Department of Crop Production and Agricultural Technology, University of Castilla-La Mancha, Albacete, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Copete
authors.affiliation: Higher Technical School of Agronomy and Forestry Engineering, Department of Crop Production and Agricultural Technology, University of Castilla-La Mancha, Albacete, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Herranz
authors.affiliation: Higher Technical School of Agronomy and Forestry Engineering, Department of Crop Production and Agricultural Technology, University of Castilla-La Mancha, Albacete, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Ferrandis
authors.affiliation: Botanical Institute of the University of Castilla-La Macha, Albacete, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Copete
mesh_terms: D004463:Ecology; D017753:Ecosystem; D018525:Germination / Q000502:physiology*; D057445:Plant Dormancy / Q000502:physiology*; D012621:Seasons; D012639:Seeds / Q000502:physiology; D031365:Sideritis / Q000502:physiology*; D012987:Soil; D013696:Temperature
chemical_list: D012987:Soil
keywords: Dormancy break; dormancy induction; ex-situ propagation; physiological dormancy; plant population and community dynamics; seed longevity; soil seed bank