Stem cutting of four species from the genus Tibouchina Aubl.(Melastomatacea Juss.)
The genus Tibouchina Aulb. (Melastomatacea Juss.) presents two hundred species approximately in Brasil and is recommended
for ornamental use because its beautiful flowers. This work aimed the
rooting response for stem cuttings of Tibouchina fothergillae, T. granulosa, T. pulchra and T. sellowiana using different
concentrations of indolebutyric acid (IBA). The semi hardwood cuttings were produced in spring/2004 with 10cm length,
maintaining a pair of half leaves. The cuttings bases were treated with 0, 1500 and 3000 mgL-1
IBA, in alcoholic solutions(50%) for ten seconds. They were planted in polypropylene boxes with medium vermiculite and maintained
for 30 days to T. fothergillae and 70 days to others species in greenhouse, when were evaluated rooting percentage, length and number of
roots, cutting with callus percentage and its survival. Data were analyzed using a completely randomized in a factorial
arrangement for three different concentrations of IBA and four species tested with four replications and twenty cuttings to
experimental unit. The species which presented the higher rooting percentage was T. fothergillae (100%). T. sellowiana, T.
pulchra and T. granulosa showed 57.70%, 26.67% and 16.67% of rooting, respectively. The concentration which represented
the biggest effect on rooting percentage was 3000 mgL-1 IBA (59,68%). Cuttings of T. fothergillaetreated with 3000mgl-1
IBA showed the biggest number of roots (39.57) while cuttings of T. granulosa without IBA presented the higher average
length of roots (13,14).