Multiplicação in vitro e aclimatização de mudas micropropagadas de Heliconia chartacea (Lane x Barreiros) var. Sexy Pink

Abstract

The ornamental tropical heliconia plants are of great interest in Brazilian floriculture, and among them stands out Heliconia chartacea (Barry x Lane) var. Sexy Pink, whose micropropagation allows to obtain large-scale plants, with genotype identical to the common ancestor and high health status. In order to determine the composition of the culture medium and the effect of cytokinin Benzylaminopurine (BAP) and Tidiazuron (TDZ) for multiplication in vitro, the effect of different concentrations of sucrose in the culture medium for rooting in vitro and the influence of different substrates on the acclimatization of plants of H. chartacea var. Sexy Pink., We tested different levels of nitrogen and calcium in the basic culture medium MS (Murashige and Skoog, 1962) in combination with BAP, TDZ and BAP, with or without coconut water. Treatment with MS medium plus 0.25 mg L-1 TDZ, followed by MS treatments and 3 mg L-1 BAP and MS with 220.00 mg L-1 and 0.25 CaCL2.2H2O mg L-1 TDZ presented the best answers to issue and size of the shoots, confirming Nannetti & Pinto (1995), who reported a need for different concentrations of cytokinins for different levels of nitrogen and calcium to the development of the sprouts Heliconia sp. It was also found that for variations of concentrations of BAP no statistical differences between treatments with 2 and 3 mg L-1 with or without coconut water, however, concentration 2 mg L-1 and 10% water Coconut comferiu best results proving to be the best medium for the multiplication of H. chartaceae var. Sexy Pink. For rooting, plantlets with 3 to 5 cm high were inoculated in culture medium MS with half the salt concentration (MS/2) supplemented with different concentrations of sucrose (0, 15, 30, 45 and 60 g L-1). The absence of an endogenous source of sugar did not inhibit root formation, but these were few and very thin. When the sucrose concentration used was 15 to 60 g L-1, production of root biomass was increased giving the plant a greater chance of establishment for the acclimatization stage. Doses of 45 and 60 g L-1 decreased the dry mass of roots thus enabled the formation of roots thickened and brittle due to greater accumulation of water in tissues. There were no significant differences in the average number of roots per explant in different concentrations of sucrose the exception of the control treatment, but comparing the dry weight of roots, one can ascertain that the addition of sucrose at a concentration of 30 g L-1 in MS medium, showed the highest increase in mass, proving to be the best medium for rooting of H. chartacea var. Sexy Pink. For acclimatization, we used six types of substrate, T1: Bioplant® T2: Coconut fiber, T3: Coir + Bioplant®, T4: Coir + Earthworm casting; T5: Coir + Bioplant® + Earthworm casting and T6: sand, vermiculite. The survival rate ranged from 83% to 92% with no statistical differences between treatments. The T3 gave a further development of the root system than others, and the T1 and T6 substrates, those who had a less developed. There was a greater accumulation of dry matter in shoots of plants acclimatized in T2, followed by its variations T3, T4 and T5, favoring more vigorous seedlings. The substrate prepared with coconut fiber was what provided the greatest increase in dry mass of shoot and root, the most suitable for acclimatization of Heliconia chartacea (Barry Lane x) var. Sexy Pink.