Indoleacetic acid and gibberellic acid were added to decapitated lightgrown 'Alaska' pea seedlings as substitutes for the intact apex in the control of apical dotiinance. Of various concentrations and combinations tried, a conrbintation of 1 % indoleacetic acid 1 % gibberellic acid was the most inihibiting to side bud growth. The greatest degree of hormonally induced side bud inhibition was ach...

The phytochrome-mediated attachment of mung bean (Phaseolus vulgaris L., var. Oklahoma 612) root tips on glass is quickly affected by indoleactic acid and abscisic acid at concentrations of 10 nm or less. Indoleacetic acid induces detachment, whereas abscisic acid induces attachment. Both plant regulators rapidly antagonize the action of the other. None of several cytokinins, gibberellins, and ...

The short term effect of 11.4 mum indoleacetic acid on the incorporation of (methyl-(3)H)thymidine into DNA in vegetative tobacco (Nicotiana tabacum cv. Wis. 38) stem segments has been investigated. In segments that are defoliated, inverted, and kept in the dark for 7 hours, indoleacetic acid very rapidly (about 60 minutes) and strikingly initiates thymidine incorporation into DNA. The time req...

Indole-3-acetic acid, alpha-naphthylacetic acid, and 2,4-dichlorophenoxyacetic acid (0.001 to 1.0 mm) inhibit the nyctinastic closure of excised Albizzia leaflet pairs; antiauxins and auxin analogs are ineffective, and the auxin effects seem not to be mediated by ethylene. Indoleacetic acid (0.001 to 0.1 mm) also promotes rhythmic opening in the dark, but is ineffective during that phase of rhy...

A neutral substance, convertible to an acid auxin, is present in various plant extracts (5, 9) and chemical preparations (9). As indicated by a number of biological tests, the neutral substance is in all likelihood 3-indole acetaldehyde and will for convenience be designated by this name in the present paper. In a previous paper (11) it was shown that 3-indole acetaldehyde is rapidly converted ...

The effect of pH on (36)Cl(-) movement into coleoptile cells (Avena sativa L. cv. Garry) was investigated and compared with effects of indoleacetic acid. (36)Cl(-) uptake, but not efflux, is stimulated when coleoptile sections are placed in media adjusted to pH levels from 5 to 3 after a preincubation period at pH 6.5. The enhancement is seen within 2 minutes, is not correlated with growth, and...

Activity of indoleacetic acid oxidase in partially purified extracts from cotton is stimulated by small amounts of malate, succinate, fumarate, and other plant acids. The stimulation is apparently due to inhibition of catalase, which is detectable in certain preparations. The lag phase of indoleacetic acid oxidation by crude preparations is eliminated by steps in processing which conceivably ei...