Multiplicação in vitro e aclimatização de Melocactus sergipensis

Melocactus sergipensis is a newly discovered species, endemic to the state of Sergipe and critically endangered. The objective of this research was to establish a protocol for micropropagation and acclimation of M. sergipensis plants. The experimental setting was a completely randomized design, with four treatments, 10 replicates and in each experimental unit an explant was introduced. Explants were obtained from medial sections of the stem of approximately 5 mm. The nutrient medium was ½ salts of MS supplemented with 30 g L -1 of sucrose, gelled with 7 g L -1 of agar and with the following concentrations of phytoregulators: 6-benzylaminopurine (BAP) [0,0; 1,5; 3,0 and 6,0 mg L -1 ] and naphthalenoacetic acid (ANA) [0,0; 1,5; 3,0 and 6,0 mg L -1 ] and the BAP/ANA combinations [0,0; 1,0/0,5; 2,0/1,0 and 4,0/2,0 mg L -1 ]. The mean values of (shoots per explant, stem height and stem diameter) and percentage of calogenesis, rooting explants, survival of explants and shoots and weight of fresh matter were evaluated. Data were submitted to analysis of variance and means were compared by the Tukey test, 5% significance. There were no significant differences between treatments in relation to bud formation, callus, shoot and bud survival, stem height, stem diameter, and cracked weight. Nutritional supplementation with 1,0/0,5 BAP/ANA mg L -1 promoted a higher shoot formation. During the ex vitro phase, 70% of the normal shoots and 0,1% of the hyperhydric shoots survived.