Effect of different culture tube caps and concentrations of activated charcoal and sucrose on in vitro growth and budding induction of Annona glabra L.

Abstract

The present work evaluated the effects of different types of culture flask seals and varying concentrations of sucrose and activated charcoal on the in vitro induction and growth of buds of Annona glabra L.; an edible fruit-producing species popularly known as "araticum". Nodal segments obtained from A. glabra plants maintained in green houses were surface sterilized and inoculated into a WPM culture medium solidified with 7 g L-1 of agar and supplemented with sucrose (0.00; 29.21; 58.63 and 116.84 mM), activated charcoal (0.0 and 2.0 g L-1), and 250 mg L-1 benomyl. In addition to the varying concentrations of sucrose and activated charcoal, we evaluated the efficiency of two types of test tube seals: PVC film, and cotton plugs. All possible combinations of caps and nutrient media were tested with 4 repetitions with 5 tubes each, evaluating the number of buds, the percentage of explant responses, the number of expanded leaves per bud, the length of the largest leaves, leaf abscission, and the length and dry weight of the buds. The type of seal influenced organogenesis in nodal segments of A. glabra, and no bud induction was observed in the absence of sucrose. The largest number of expanded leaves were obtained when 58.42 mM of sucrose was used in tubes sealed with cotton plugs, and leaf abscission was halved in the presence of activated charcoal. The greatest bud length and dry weight were obtained in tubes sealed with cotton plugs and in the presence of activated charcoal.