plants Review Reinvigoration/Rejuvenation Induced through Micrografting of Tree Species: Signaling through Graft Union Isabel Vidoy-Mercado 1,2, Isabel Narváez 2,*, Elena Palomo-Ríos 2 , Richard E. Litz 3, Araceli Barceló-Muñoz 1 and Fernando Pliego-Alfaro 2 1 Fruticultura Subtropical y Mediterránea, IFAPA Centro de Málaga, Unidad Asociada al CSIC, Cortijo de Cruz s/n, 29140 Málaga, Spain;
[email protected] (I.V.-M.);
[email protected] (A.B.-M.) 2 Departamento de Botánica y Fisiología Vegetal, Facultad de Ciencias, Campus de Teatinos s/n, Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM-UMA-CSIC), 29071 Málaga, Spain;
[email protected] (E.P.-R.);
[email protected] (F.P.-A.) 3 Tropical Research & Education Center, University of Florida, 18905 SW 280 Street, Homestead, FL 33031-3314, USA; relitz@ufl.edu * Correspondence:
[email protected] Abstract: Trees have a distinctive and generally long juvenile period during which vegetative growth rate is rapid and floral organs do not differentiate. Among trees, the juvenile period can range from 1 year to 15–20 years, although with some forest tree species, it can be longer. Vegetative propagation of trees is usually much easier during the juvenile phase than with mature phase materials. Therefore, Citation: Vidoy-Mercado, I.; reversal of maturity is often necessary in order to obtain materials in which rooting ability has been Narváez, I.; Palomo-Ríos, E.; Litz, restored. Micrografting has been developed for trees to address reinvigoration/rejuvenation of elite R.E.; Barceló-Muñoz, A.; selections to facilitate vegetative propagation. Generally, shoots obtained after serial grafting have Pliego-Alfaro, F.