Establishment and in vitro multiplication of Calophyllum brasiliensis

Abstract

Calophyllum brasiliensis, known as Guanandi, is a Brazilian native wood species with economic relevance value due its high wood quality and its medicinal properties. Guanandi's commercial propagation is achieved by seeds that present cutaneous numbness, recalcitrance and low germination rate. The aim of this work was to improve the germination and in vitro multiplication of Guanandi. For the germination experiment, seeds were first manually scarified, to remove the endocarp and the integument, and then immersed in different concentrations (0, 25 and 50%) of potassium nitrate (KNO3) for 24 h at room temperature. After that, seeds were disinfected and inoculated on solid WPM medium. The in vitro germination was significantly affected by KNO3. Germination speed index (GSI) and germination percentage were higher (5.4 and 66,67%, respectively) on treatment with 25% of KNO3 in comparison to the controls (3,5 and 40,0% respectively). For the multiplication experiment, axillary buds, isolated from in vitro seedlings, were inoculated in solid WPM medium with 2 g L-1 of active charcoal, supplemented with TDZ (thidiazuron), Kin (6-furfurylaminopurine), BA (benzyladenine) or 2iP (isopentenyladenine) at concentrations of 0, 8 or 16 µM. After 30 days it was observed that the culture medium supplemented with 8 μM Kin promoted the highest multiplication rate (3.6 shoots explant-1) without medium oxidation. Therefore, Guanandi seed germination can be improved with KNO3 treatment and the in vitro multiplication best controlled by supplement of kin at concentration of 8 μM, which also avoided the medium oxidation.