In Vitro Micrografting of Mature Carob Tree (Ceratonia siliqua L.)

A micrografting technique was developed for Ceratonia Siliqua using in vitro germinated seedlings as root- stocks and apex or shoot cultures (established from mature female tree source) as microscions. In vitro germinated seed- lings were decapitated and used as rootstock. Mature explants were initiated on Murashige and Skoog medium containing 30 g/l sucrose, and 0.5 mg/l 6-benzylaminopurine, then transferred on the multiplication medium (Murashige and Skoog + 0.5 mg/l 6-benzylaminopurine + 0.1 mg/l gibberellic acid + 0.1 mg/l indol-3- butyric acid). Micrografts could be easily cultured on the same medium and developed after one month. Grafting success has been dependent on the method of grafting. The micrografting on hypocotyl (central grafting) method was significantly more successful (92, 50%) than the other grafts methods. The compatible graft union was observed one month after grafting. The histological cuttings showed that the graft union formation was initiated by the development of the callus bridge at the interface between scion and rootstock, after that, new vascular elements including vessels and tracheids were seen across the interface zone.