“…Concentrations of growth regulators in the growth medium used for cactus species range from 0, as in the case of in vitro culture of Mammillaria gracilis Pfeiff. (Balen et al, 2004), to low, intermediate or high levels of cytokinins, such as BA (4.4, 6.7, 8.8, 13.3 and 44.4 µM), employed alone in several species of Mammillaria (Mammillaria longimamma, Mammillaria stylothele), Turbinicarpus and Escobaria vivipara, or in combinations with an auxin like NAA (2.7-10.7 µM) or IAA (2.9-5.7 µM) with Notocactus (Mata Rosas et al, 2001;Dávila-Figueroa et al, 2005;Medeiros et al, 2006;Quiala et al, 2009). Growth media have been supplemented with Kin at 0, 4.6, 13.9, 22.3, 27.9 and 46.5 µM in the absence or presence of an auxin (IAA or NAA), and zeatin has been added at 4.6 and 22.3 µM for in vitro multiplication of species of the genera Pediocactus, Sclerocactus and Toumeya (Clayton et al, 1990).…”