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Báo cáo lâm nghiệp: "Storage of non-dormant hardwood seeds"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Storage of non-dormant hardwood seeds. | 92s Ann. Sà. For. 1989 46 suppl. 92s-94s Forest Tree Physiology E.Dreyer etal. eds. Elsevier INRA Storage of non-dormant hardwood seeds new trends c. Muller1 and M. Bonnet-Masimbert2 11NRA-CRF Laboratoire de Graines Foret d Amance Champenoux BP 35 54280 Seichamps and 2INRA Station dAmélioration des Arbres Forestiers Ardon 45160 Olivet France Introduction More than 60 of forestry seeds especially hardwood species are in a more or less deep dormancy state. As a consequence of its important genetic variability this dormancy is very heterogeneous it can vary from year to year from seed lot to seed lot and between seeds within a seed lot. Generally it is a type of physiological dormancy caused by a germination-inhibiting mechanism in the embryo which often requires a long prechilling period 1-8 months to eliminate it. Sometimes this physiological dormancy can be associated with a physical impermeability of the seed coat to water or with a morphological underdevelopment of the embryo. Nurserymen are generally unaware of the dormancy requirements of their seeds which has resulted in an enormous waste of seeds and mediocre yields in the nurseries. Materials and Methods The classical method of breaking the dormancy stratification i.e. pretreatment on a wet me dium at 3-4 C is limited in dealing with the heterogeneity within a seed lot. A new and original methodology has been developed on the basis of Polish research work applied to beechnuts Suszka 1975 . It eliminates the dormancy before storage allowing a continuous supply of non-dormant seeds ready to germinate Dormancy is eliminated by pretreatment without medium. Seeds are hydrated maintained at a controlled level of moisture content permitting the removal of dormancy without allowing germination and finally dehydrated to below 10 moisture content MC before storage. This method allows a fast and uniform germination in the laboratory as well as in the nursery. We have developed this methodology further in our laboratory