Propagation, growth, retardation, flower induction, and postproduction performance of Tibouchina urvilleana (DC.) Cogn.

Propagation of Tibouchina, urvilleana by top cuttings or young, nodal stem cuttings covered with polytene provided the best rooting results. Depending on the season, two to three weeks after sticking 100% of the cuttings had developed roots. Plantlets grew well on ebb and flood benches when they wer e supplied with a nutrient solution developed specifically for Tibouchina. Growth of Tibouchina plants placed under cold house or warm house condition s resulted in plants with fewer and shorter internodes and a low growth rat e at lower ambient temperature than plants placed under warm conditions. Th e latter needed growth retardants, and the effects of four growth retardant s in different concentrations were analysed. Optimal concentrations were wi th chlormequat: 200 ppm ai.; daminozide: 3,400-4,300 ppm ai.; flurprimidol: 0.15 ppm ai.; butrazol: 1-5 ppm ai., which all gave a retarded height of t he plants concomitantly with growth of lateral shoots. The factors responsible for induction of flowering in Tibouchina were teste d at day lengths of 8, 12, and 16 hours, but the results showed an ambiguou s effect of the different day lengths. Thus, it may indicate that Tibouchin a is a day-neutral plane. Ethylene had a contributory effect on leaf abscis sion during simulated transport. In conclusion it can be stated that Tibouchina urvilleana has a potential a s an interior potted plant, but development is not yet finished.