Avaliação dos agentes desinfestantes na esterilização superficial de explantes caulinares para o estabelecimento in vitro de guavira

Abstract

Campomanesia adamantium (Cambess.) O. Berg (guavira) is a native species of Cerrado, with potential for sustainable exploration due to the nutritional quality and diversity in the forms of exploitation of fruits and medicinal plant properties. Naturally guavira is propagated by seeds, but with limitations, attributed mainly to the recalcitrance and loss of germination viability. Due to the difficulty of sexual propagation and lack of information about the culture, the development of an advanced technique of vegetative propagation of culture, provide an alternative route to obtain seedlings of the species, overcoming the limitations of the germination process. Therefore, this study aimed to establish a protocol for sterilization and in vitro establishment of shoot explants of guavira. Experiment 1: Effect of the Agent mercuric chloride at the following concentrations: 0.0 (control - sodium hypochlorite at 2.5%), 0.025, 0.050, 0.075 and 0.100%. Experiment 2: Agent benzalkonium chloride concentrations 0.0 (control - sodium hypochlorite 2.5%), 0.025, 0.050, 0.075 and 0.100%. Experiment 3: Effect of hydrogen peroxide added to sodium hypochlorite at concentrations of 0.0 (control - sodium hypochlorite at 2.5%), 10, 20, 30 and 40%.The surface sterilization of Guavira's explants with 0.025% mercuric chloride reduced the bacterial contamination of 65.6% to 18.8% and oxidation of the explants, from 53.1% to 12.5% compared to the explants treated with hypochlorite sodium (control). The concentrations of mercury chloride tested in this experiment were not effective in controlling fungal contamination. The largest number of established explants (9.4%) was obtained in the treatment with 0.1% mercuric chloride. Although no statistical significance between the concentrations of benzalkonium chloride and the level of contamination, it is remarkable a decrease of explants contaminated by bacteria compared to control. The addition of hydrogen peroxide in concentrations of 30 and / or 40% when sodium hypochlorite 2.5% was effective in disinfecting the Guavira’s explants, controlling the levels of fungal contamination and oxidation, allowing to obtain a larger number of established explants in vitro.