The present investigation was conducted during the period between 2012 till 2013 in the Tissue Culture Laboratory of Horticulture Department, Faculty of Agriculture, the University of Mansoura, Egypt. Seeds of volkamer lemon rootstock were grown in vitro on Murashige and Skoog (1962) basal medium at full strength, hypocotyls of the resulted plantlets used as source to prepare micro-cuttings. Micro-cuttings before cultured on the same medium subjected to five treatments included infection with Agrobacterium rhizogenes and addition of antioxidant (Vitamin B₁₂) at 1.0 or 1.5 mg/L either solely or in combinations. Untreated control micro-cuttings cultured on the same medium were considered. Representative samples were taken at random at 15^th day later treatment date to be used for determining four internal chemical constituents present in the treated micro-cuttings. Five weeks later the effect of such treatments on adventitious roots induction and shoots multiplication evaluated through measurement of concerned parameters. The obtained results pointed to the treatment of A. rhizogenes inoculation in the presence of   vitamin B₁₂ at 1.5 mg/L in culture medium “T₅" to be the most effective one to produce the best rooting performance, root number and diameter as well as  roots fresh and dry weights. The same treatment also increased rooting% and roots length over the control micro-cuttings as well as it causes an increase on carbohydrates, nitrogen contents, phenols content and C/N ratio. Otherwise, it showed an inferior effects on start rooting, explants survival% and rooting% compared with vitamin B₁₂ treatments “T₂&T₃" effect. Since the later two treatments succeeded to record significantly the earliest start rooting, the highest frequency of micro-cutting survival and rooting percentages. It is worth to say herein that the treatment of A. rhizogenes inoculation only “T₁" also has a positive effect to early start rooting and to enhance chemical constituents determined in basal part of treated micro-cuttings.