Effect of inhibitors of auxin polar transport on the growth induced by indole-3-acetic acid and indole-3-butyric acid in excised stem of tulips

Marian Saniewski, Elżbieta Węgrzynowicz-Lesiak, Justyna Góraj, Kensuke Miyamoto, Junichi Ueda

Abstract: In the present study we report the effect of inhibitors of auxin polar transport, NPA, TIBA and morphactin IT 3456, on indole-3-acetic acid (IAA)and indole-3-butyric acid (IBA)-induced growth of excised stem from growing tulips (Tulipa gesneriana L.) cv. Apeldoorn, after removal of flower bud and all leaves. Auxins, IAA and IBA, at a concentration of 0.1% in lanolin paste were applied on the top of explants and inhibitors of auxin polar transport in the middle of the 4th internode, and explants were kept in water. IAA and IBA similarly induced growth of tulip stem isolated from growing shoots and all inhibitors tested substantially inhibited the growth of lower internodes (the 1st, 2nd and 3rd) but stimulated growth of the 4th (last) internode. These data suggest that these inhibitors of auxin polar transport blocked auxin transport from the 4th internode and in consequence higher levels of auxin accumulated in the 4th internode stimulated the growth of the internode.

Keywords: auxin polar transport inhibitors; indole-3-acetic acid; tulips

Date published: 2017-07-26