Rajeunissement chez le Sequoia sempervirens: effets du microgreffage in vitro

In vitro micrografting of Sequoia sempervirens was used as a rejuvenation method: apices were collected from in vitro cultured shoots issued from a 500-year-old tree; the rootstocks originated from a 1-year-old tree. Only a few grafted apices survived. Once producing leafy shoots, they exhibited some juvenile morphological and physiological characteristics. Some scions were isolated and rooted in a new medium. Although the restoration of the orthotropy is very difficult, a few of the rooted plantlets were orthotropic and this characteristic was maintained after acclimatization in greenhouses. Therefore, the in vitro micrografting of Sequoia sempervirens can be considered as a rejuvenation method that must be improved. Key words: Sequoia sempervirens, in vitro micrografting, rejuvenation, orthotropy.