Protocolo de micropropagação da Conobea scoparioides Benth.-Plantaginaceae

Abstract

The Conobea scoparioides Benth., popularly known as pataqueira, is a semi-aquatic herbaceous plant with aromatic and medicinal properties. It belongs to the Plantaginaceae family and it was originated in the Amazon. In the State of Pará it is very used for treating beriberi and in the formulation of an eau de cologne of great economic interest, therefore causing its indiscriminate exploitation. Currently, there is no efficient propagation system to meet the market demands. The aim of this work was to develop an in vitro micropropagation protocol for pataqueira. Within this purpose, three steps were conducted: 1- shoot multiplication; 2- the effect of subcultivation in the plantling formation; and 3- the effect of substrates in the acclimatization and seedling formation. The explant source for the in vitro culturing was obtained from micropropagated and field-grown plants. In vitro cultivation occurred in growth rooms with a 25+3 0C temperature and 16 hour photoperiod, while the acclimatization was conducted under a screen of 70% shade, with an average temperature of 30+2°C. In the first step, viable shoots were obtained in the Murashige & Skoog (MS) culture medium through apical and nodal stem segments in the absence and in the presence of 1 mg.L-1 of 6-Benzilaminopurina (BAP). The percentage of rooting and the number of roots was superior in the liquid 1/1 MS medium supplemented with 0.5 mg.L-1 of Indol butyric acid (AIB). The pataqueira is micropropagated through the MS culture medium, being optimized in the presence of growth regulators BAP and IBA, using the apical and/or nodal segments. In the next step, the fourth subculture presented higher means for all variables with the exception of height of the highest shoot and presented a mean rate of shoot/explant of 24, while the fifth subculture induced the highest senescence percentage and the smallest percentage of shoots and roots, but presented high means in the number of shoots with height ≥ 1 < 2 cm, number of shoots ≥ 2 < 3. The first to fourth subcultures are viable in a span of thirty days to the formation of pataqueira seedlings in vitro. Regarding the third step, the survival of seedlings in all substrates was 100%. The mixture of soil, sawdust and bovine manure presented the highest mean values for most of the evaluated variables, while the substrate consisting of only soil promoted the least increase in the plants. The tested substrates are adequate for acclimatization. Highlighted the soil+sawdust+matured bovine manure substrate as most suitable within the studied mixtures for the formation of viable seedlings.