ABSTRACT
Cultures of plant tissues may require a certain plant growth regulator or combination in one stage of growth, and then a completely different one or the absence of all PGRs in another. For example, in micropropagation stage I, the initiation phase, a combination of auxins and cytokinins may be needed. In stage II, the multiplication stage, most typically cytokinins are used to stimulate shoot proliferation. In stage III, the root formation stage, most often auxins are used to induce roots. In stage IV, acclimatization, the herbicidal triazoles, paclobutrazol (PBZ), and uniconazole (UNI), have been shown to enhance survival in the case of Prunus serotina (Figure 4.2).
