In vitro shoot proliferation of Tectona grandis L. (teak) using temporary immersion system (TIS) and different concentrations of BA is presented. Shoots grown on semi-solid MS medium supplemented with 2% (w/v) sucrose and 4.44 µM of BA were used as starting materials. In the TIS, three BA concentrations (2.22, 4.44 and 6.66 µM) and a cytokinin-free medium (CK-free medium) were assayed. A high average number of shoot was reached, applying 4.44 and 6.66 µM of BA (7.7 and 10.3 shoots/explant), respectively. The high BA concentrations decreased the accumulation of phenolic compounds and the deposition of lignin in the vascular cells of the teak shoots. The morphometric analysis by scanning microscopy revealed that the leaves of the shoots cultured in the TIS in Ck-free medium and with 2.22 and 4.44 µM of BA showed elliptical stomata; however, in the leaves developed with 6.66 µM of BA, the stomata were majorly ring-shaped, raised and wide open. Deformed stomata with broken epidermis of the guard cells, typical of hyperhydric leaves, were also observed. The survival percentages after ex vitro rooting on the IBA (492.1 µM) solution were higher in plantlets from CK-free medium and with 2.22 µM of BA, (96.7 and 91.7%, respectively) than those cultured on semi-solid medium (73%). The shoots from both TIS treatments developed a good root system. Plantlets from 6.66 µM of BA showed the lowest survival percentages (60%). A survival percentage was 100% two weeks after transplanting, and three months after ex vitro transfer, the plants were ready for field plantation. Here we present the first report of the successful propagation of teak by TIS.

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