Báo cáo khoa học: Rejuvenation of Quercus robur

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Rejuvenation of Quercus robur...
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Báo cáo khoa học: "Rejuvenation of Quercus robur" article Original of Quercus robur Rejuvenation P Evers E Vermeer, S Eeden van IBN-DLO, Institute for Forestry and Nature Research, Department of Urban Ecology, Section of Ecophysiology, POBox 23, 6700 AA Wageningen, The NetherlandsSummary — Stem sections and some branches, 30 cm in length, of mature Quercus were cut to in-duce the formation of rejuvenated shoots as initial material for in vitro propagation. Up to 100-year-old trees were used and topophysical effects were taken into account. In vitro rooting of shoot tipstaken from this material showed a lower efficiency than embryo-derived cultures, but the fact thatrooting occurred indicates some degree of rejuvenation. The influence of stem topophysis as well asgenotype remains unclear.rejuvenation / Quercus robur / topophysis / adventitious neoformationRésumé — Réjuvénilisation de Quercus robur. Des segments de la tige principale ainsi que desbranches ont été prélevés sur des chênes âgés de manière à induire la formation de pousses reju-vénilisées destinées à la multiplication in vitro. Des arbres de plus de 100 ans ont été retenus et leseffets de topophysis ont été pris en compte. L’enracinement in vitro de ces pousses est plus difficileque celui produit dans des cultures d’embryons. Mais il indique toutefois un certain degré de rejuvé-nitisation. L’influence de la topophysis et du génotype de l’arbre n’a pas été élucidée.réjuvénilisation / Quercus robur / topophysis / néoformation adventiveINTRODUCTION have therefore been proposed before (eg, Romberger, 1976) but were not so often effectuated. Also in Quercus robur, thisMicropropagation of woody species has difference was observed and some rejuve-been reported to be limited by rootability in nation attempts implemented (Chalupa,many surveys (eg, Bonga and Durzan, 1984; Meier-Dinkel, 1987; Vermeer and1987) of shoot tips harvested from adult Evers, 1987; Evers et al, 1988; Ballestertrees. Embryo-derived cultures, used as et al, 1990). In Dutch forestry, this speciesthe juvenile reference, in general proved is used both for urban and planted standto be more efficient in growth rate, axillary purposes. For urban areas, selected elitebranching and rooting than adult tree- genotypes are used, usually still propagat-derived cultures. Rejuvenation strategies ed through grafting. For stands, acorns From the 65-year-olds, stem and branch sec- harvested from selected seed stands.are tions were taken. All of the 8-year-old and two- means that the development of micro-This thirds of the 100-year-old sections were taken topropagation techniques starting from both the greenhouse due to a lack of space; for theadult and juvenile material are required 65-year olds, 3 sections out of each of the totaland, at the same time, provide the oppor- number of sections present in each fourth por-tunity to study the consequences of matu- tion of the stem height were randomly selected. This reduction was again due to the lack ofration. Maturation is often associated with greenhouse space.the loss of rootability and with the successof promotion of flowering (Libby, 1974). comparison For the 65-year-olds, was a made between 6 genotypes that form epicormicThe results presented in this paper reflect shoots (defined as any stem shoot occurring inthe attempts to attain rejuvenation through intact trees) readily and those that do not. Inthe application of some techniques on the the regenerated or activated shoots from t ...