Crescimento in vitro de pequizeiro (Caryocar brasiliense a. St.-hil.): influência da polaridade e luminosidade

Abstract

Due to the great devastation of cerrado, the natural propagation of Caryocar brasiliense has been seriously affected. Besides, its seeds present serious problems of coat dormancy and possible presence of inhibitors. In this context, plant tissue culture becomes an alternative for the especies propagation. The objective of this work was to evaluate the effect of the polarity on leaf and nodal explants of Caryocar brasiliense during in vitro cultivation and verify the influence of light on callus and shoot induction. The study of the polarity influence on callus induction was observed inoculating leaf segments on WPM. The influence of light on callus induction was investigated inoculating leaf explants on WPM supplemented with 1.0 mg L -1 TDZ and 2.0 mg L-1 2.4-D, and maintained under the presence and absence of light. The influence of light on shoot induction was evaluated inoculating nodal segments on WPM supplemented with 0.75 mg L-1 BAP and 0.05 mg L-1 NAA and maintained in the presence and absence of light. For callus induction, inoculation of leaf explants with the abaxial surface in contact with the cultivation medium on the horizontal position showed better results. For nodal explants, the horizontal orientation showed to be more effective resulting in an average production of 3.88 shoots/explant when compared with the vertical position (1.5 shoots/explant). Callus induction was 38.31% higher in the absence of light. Shoots induced on nodal segments developed better in the presence of light.