부산대학교 도서관

Micrografting of Four Sahelian Trees (Acacia senegal, Faidherbia albida, Tamarindus indica and Ziziphus mauritiana) with a View to their Rejuvenation. This paper proposes a protocol of rejuvenation of four Sahelian ligneous species : Acacia senegal, Faidherbia albida, Tamarindus indica and Ziziphus mauritian. It consists in aseptically removing a small scion (5-10 mm in length) and in micrografting it on to a seeding grown in vitro used as rootstock. The main elements of success are the age of the rootstock (two to six weeks depending on species), the level of grafting (on hypocotyl instead of epicotyl) and the origin of the scion (apex have higher growth after micrografting than axillary buds). The method developed was applied to the restoration of juvenile traits of adult trees. The main criterion is the rooting ability of microcuttings sampled on scions, after micrografting. Rooting competence restoration depends on the species, the nature of the first copy of the donor tree and the number of cycles of micrografting. The rejuvenation was more definite for F. albida, mobilised by root cuttings. In this case, one third of the microcuttings rooted after the first cycle of micrografting and 75 % after the second. For 2. Mauritiana mobilised by horticultural budding, 25 % of microcuttings were rooted after the second successive micrograft. No restoration of rooting competence was obtained with A. senegal and T. indica mobilised by cutting.