Whole plant regeneration from the shootapical meristem of Opuntia ficus-indica Mill. (Cactaceae)

Lack of reliable and quick protocols for the in vitro culture of the prickly-pear has proven to be one of the hindrances in the application of transformation protocols to this crop. Here we present a protocol for the initiation of shoot apex elongation and rooting of these shoots. Shoot apices were isolated from germinated seedlings and placed on MURASHIGE and SKOOG (MS) medium containing 6-benzylaminopurine (BA) and gibberellic acid (GA). When shoots became visible, the explants were transferred to MS-medium containing BA and indole-3-acetic acid (IAA). Once shoot elongation occurred, they were transferred to MS-medium containing only one plant growth regulator, IAA. Within three weeks, the shoots began to root and could be transferred to soil. At the same time, this protocol outlines a method for the mass propagation of the prickly-pear based on the proliferation of apical buds obtained from shoots in the elongation phase.