Meristem-Tip Culture for Propagation and Virus Elimination

The essence of meristem-tip culture is the excision of the organized apex of the shoot from a selected donor plant for subsequent in vitro culture. The conditions of culture are regulated to allow only for organized outgrowth of the apex directly into a shoot, without the intervention of any adventitious organs ( 1 – 3 ). The excised meristem tip is typically small (often <1 mm in length) and is removed by sterile dissection under the microscope, as in the potato example detailed in this chapter (Fig. 1 ). The explant comprises the apical dome and a limited number of the youngest leaf primordia, and excludes any differentiated provascular or vascular tissues. A major advantage of working with such a small explant is the potential that this holds for excluding pathogenic organisms that may have been present in the donor plants from the in vitro culture ( see below ). A second advantage is the genetic stability inherent in the technique, since plantlet production is from an already differentiated apical meristem and propagation from adventitious meristems can be avoided ( 3 – 9 ). Shoot development directly from the meristem avoids callus tissue formation and adventitious organogenesis, ensuring that genetic instability and somaclonal variation are minimized.

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