Indução, regeneração e caracterização morfoanatômica de calos de variedades de cana-de-açúcar

Abstract

Both the in vitro establishment and the callogenesis of sugarcane allow the mass production of quality regenerative material substantially important for genetic transformation. The overall objective of the study was to establish protocols for the efficient production of calli with the regenerative potential of varieties RB855156, RB92579 and RB867515, as well as their characterization regarding morphology and anatomy aiming the genetic transformation. The palm disinfestation was carried out by submersion in 70% ethanol and sodium hypochlorite at 2% active chlorine. Callogenesis was induced in MS medium supplied with 3,0 mg L-1 2,4-D, and the following antioxidants were evaluated PVP (75; 150; 300 and 600 mg L-1), citric acid, and ascorbic acid (7,5; 15; 30 and 60 mg L-1). Morphological characterization of calli was carried out by visual classification and regeneration was evaluated in three different moments. The anatomical analyzes were performed by light microscopy. The disinfection protocol was efficient for the in vitro establishment of varieties RB855156 and RB92579. Endogenous contamination prevented the cultivation of RB867515. The callogenesis was efficient, since 100% explants produced callus. The best antioxidant was the citric acid (7,5 mg L-1) as the explants exhibited lower oxidation rates (0,32) compared to the control (2,16). Three different types of calli were established: white compact nodular (BN); translucent friable (TF); and mucilaginous (M). Both BN and TF calli have high regenerative potential after 84 days of culture (100 and 90%, respectively). The mucilaginous callus does not regenerate. The anatomical analysis showed that there are structural differences between calli and their shoots are from organogenesis. Therefore, organogenic calli of RB855156 and RB 92579 varieties are potentially transformable due to their regenerative potential and in vitro establishment.