Aryl esters of indolebutyric acid increase root regeneration in 3-0 red oak seedlings

Abstract

Dormant 3-0 red oak seedlings (Quercusrubra L.) were given a 3-s basal dip in 20 mM solutions of indole-3-butyric acid (IBA), the potassium salt of IBA (K-IBA), N-phenyl indolyl-3-butyramide (NP-IBA), phenyl indole-3-thiolobutyrate (P-ITB), or phenyl indolyl-3-butyrate (P-IBA). Seedlings dipped in water or 95% ethanol served as controls. Fifty-six days after treatment, seedlings treated with NP-IBA and P-ITB regenerated up to 3 times more roots (48.7 and 40.0 roots, respectively) than did ethanol-treated control seedlings, which regenerated 14.3 roots. Seedlings treated with P-IBA regenerated 26 roots per seedling. Seedlings treated with NP-IBA and P-ITB had smaller leaves than IBA- and K-IBA treated seedlings. NP-IBA treated seedlings had more leaves than IBA- or K-IBA treated seedlings (155.3 vs. 59 and 53.3, respectively), but had similar leaf surface area. P-ITB-treated seedlings had similar numbers of leaves as IBA- and K-IBA-treated seedlings, but leaves were smaller in size, resulting in less total leaf area. P-IBA-treated seedlings had the greatest total leaf surface area, 1509 cm2; water- and ethanol-treated seedlings had total leaf surface areas of 1271 and 866 cm2, repectively.