Abstract: Tobacco (Nicotiana tabacum L. cv. Gexin No. 1) leaf slices were cultured in MS medium with different concentrations of auxin polar transport inhibitors (2, 3, 5-triiodobenzoic acid (TIBA), trans-cinnamic acid (CA), and 9-hydooxyflurence-9-carboxylic acid (HFCA)) and their effects on bud formation were observed. Although the effective concentrations vary with different inhibitors, all of them induced the formation of trumpet-shaped leaves. The frequencies of trumpet-shaped leaves were increased with the concentrations of inhibitors in media, and it was up to 82.1% when cultured in the medium containing 7.5 mg/L TIBA. The trumpet-shaped leaves were formed in different sites of the adventitious buds. These results indicated that inhibition of auxin polar transport could affect the morphogenesis of leaves, so the polar transport of auxin is essential for the bilateral symmetry of leaf growth.

Key words: Auxin polar transport, Tobacco, Differentiation of adventitious buds, Morphogenesis of leaves