| Abstract: | Extracts of excised tomato roots prepared with cold aqueousmethanol have been partitioned between ethyl acetate and waterand chromatograms of the two fractions bioassayed by an Avenacoleoptile straight growth test and sprayed with various reagentsincluding those giving colour reactions with indole compounds.The greater part of the auxin activity is in the aqueous fractionand chromatograms of this fraction give positive indole reactions. The aqueous fraction chromatographed with isopropanol/ammonia/watershows two zones of growth-promoting activity. The zone of lowerRf contains tryptophane and unidentified ninhydrin-positivematerial. Tryptophane accounts for the activity of the Ehrlich-positiveregion of this zone. The activity of the zone of higher Rf isassociated with ninhydrin-positive material; this activity can,by use of other solvents, be distinguished in Rf from that ofthe common amino-acids which would occur in this zone on theprimary chromatograms. Chromatograms of the aqueous fractionalso show the presence of urea and of a phenol, neither of whichare associated with the zones of growth-promoting activity. The ethyl acetate fraction, and particularly the acid fractionof this, contains growth-promoting activity which, in a rangeof solvents, always corresponds in Rf to IAA. The acid fractioncontains a growth inhibitor corresponding in Rf to the ß-inhibitorof other workers. A zone of growth-promoting activity near thesolvent front on isopropanol/ammonia/water chromatograms containsmore than one active component, but IAN appears to be absent. |
