Growth of Etiolated Sections of Pea Internode Following Exposures to Indole-3-Acetic Acid, 2,4-Dichlorophenoxyacetic Acid and 2,5-Dichlorobenzoic Acid.

Abstract

FIG. 1. Photograph of a chromatogram: 1, Gibberellin A (Stodola); 2, Mixture of gibberellin A (Stodola) and gibberellic acid; 3, Gibberellic acid. The chromatogram was developed on Munktells, Cremer-Tiselius electrophoretic paper for 46 hrs at 220 C. 100 jug of each of the gibbeiellin sweie used. rescence prodluced by concentrated sulfuric acid. Wce have found the 70 % sulfuric acid treatment preferable since it allows easier handling because the paper disintegrates more slowly. The fluorescent spots may be photographed for a permanent record. This paper chromatographic system is uiseful for the qualitative analysis of purified and partially purified preparations of the gibberellins. It satisfies the requirement for a relatively quick, easy method for detection of gibberellin A in gibberellic acid preparations. This has not been possible with the solvents previously reported. The procedure described may be useful for more complete identification of gibberellinlike compounds found in plant extracts.

Interaction of light and auxin in regulation of rooting in pea stem cuttings

“…Although a specific role for ethylene in root formation has been suggested (Linkins et al 1973), its inhibitory effect on rooting has not been confirmed (Batten andMullins 1978, Mudge andSwanson 1978). Negative components of IAA action possibly due to IAA-induced inhibitors in other growth responses have been discussed by Osborne (1958) and by Vesper and Evans (1978).…”

Further studies of synergism in slit pea test

“…Illustrative of this is the reduced elongation of slit as compared to whole sections, whereas total growth as measured by weight increase is not In this latter coinnection it seems appropriate to refer to the work of others. Osborne (11) Sections cut closer to the apex do not retain their original lateral dlinensions, but increase greatly in cross-sectional ai-ea in response to IAA. For exanmple, calculations using the data of Galston, Baker, and King (2) show that cross-sectional area increased 53 % more in 5.7 X 10-" M IAA than in water.…”

The Nature of the Growth‐Promoting Action of Coumarin

“…test solution in petri disties. Growtti was assessed after varions incnlialion periods at 26''C (in diffuse djiylight in the case of the sunflowers and heans, and in darkness in tlie case of Itie peas] hy measuring the increase in weight of the segments which runs parallel to their increase in tengtti (12,14).…”

“…the latter must act before the IAA. The lack of effect in the reverse order treatment mij^'ht also be due to some inhibitor formed dtn'inf^ IAA pretreatment (12). It h worth noting that the marked stimulatory effect of pretreatment in coumarin on subsequent growth in IAA {2 mg/l.)…”

“…It will be seen that in siihoptimal concentrations of IAA the time curve is parabolic. The curve is sigmoid if total growth instead of rate of growth is plotted against time (3,12). In optimal IAA concentrations the growth rate reaches its maximum value within 2 hours after which it decreases with time.…”