Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Rejuvenation of a 100 yr old giant sequoia (Sequoiadendron giganteum Buchholz) through in vitro meristem culture. | 183s Ann. Sci. For. 1989 46 suppl. 183S-186S Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Rejuvenation of a 100 yr old giant sequoia Sequoiadendron giganteum Buchholz through in vitro meristem culture o. Monteuuis and . Bon Association Foret Cellulose AFOCEL Domaine-de-1 Etanẹon 77370 Nangis France Introduction Vegetative propagation is currently recognized as a powerful tool for forest tree improvement to increase forest plantation yield Zobel and Talbert 1984 . However selected trees - the ortets - must develop enough to reach a sufficient size for reliable evaluation of their genetic potential which is accompanied in most cases by a significant decrease of their capacities for cloning by asexual propagation methods. In this context the possibilities of cloning selected mature tree genotypes true-to-type remain greatly influenced by the prior rejuvenation of the ortets. This problem was investigated at AFOCEL using Sequoiadendron giganteum Buchholz. Materials and Methods Plant material The mature material originated from a 100 yr old Sequoiadendron giganteum selected in situ. The easy-to-root juvenile clone used as the control consisted of young cuttings derived from a 2 yr old seedling. Experimental methods The mature and the juvenile materials were concurrently compared regarding their respective capacities for vegetative propagation using propagation by cuttings grafting and subsequently in vitro methods. These included subcultures with sequential BAP benzylaminopurine treatments Fouret et al. 1986 micrografting Monteuuis 1987a and meristem culture Monteuuis 1987b 1988 Rejuvenation of the mature material was evaluated through morphological - especially leaf form - and organogenic capacity criteria with reference to known juvenile material. In addition these observations were supported by biochemical investigations Bon 1988 . Results Under nursery conditions the mature material failed to root while the juvenile clone rooted but rooting ability
