The role of indoleacetaldehyde in IAA production from tryptophan by plants and by their epiphytic bacteria

Tryptophan, tryptamine, or indolepyruvic acid were applied to 2 systems: a bacterial (pea stem sections containing the epiphytic bacteria) and a plant system (pea stem sections under sterile conditions). In the plant system, the production of indoleacetic acid and indoleethanol (tryptophol) from each applied indole derivative is clearly reduced by the aldehyde reagents bisulfite and dimedon, respectively. Indoleacetaldehyde is chromatographically detected after alkaline liberation from its bisulfite addition product. In the bacterial system, the production of indoleacetic acid and indoleethanol is likewise reduced by bisulfite and dimedon. However, after tryptophan or tryptamine application, we could not detect indoleacetaldehyde in the described way. In one case only, namely tryptamine application to the bacterial system, indoleethanol production (contrary to indoleacetic acid production) is scarcely reduced by the aldehyde reagents. This indicates a bacterial pathway tryptamine → indoleethanol which bypasses indoleacetaldehyde.     

Interactions between Plants and Epiphytic Bacteria Regarding Their Auxin Metabolism VI. The Influence of the Epiphytic Bacteria on the Content of Extractable Auxin in the Plant

Sterile plants of maize, pea, and cucumber contain less auxin (extracted with methanol or ether) than nonsterile ones. The auxin content is restored within one day by reinfecting sterile plants (or only the shoots, with roots and culture medium remaining sterile) with epiphytic bacteria strains able to produce IAA or with soaking water of nonsterile seeds. Reinfection with bacteria, strains unable to produce IAA is ineffective. — The possibility of a bacterial auxin production during methanol extraction was excluded.     

Trijodbenzoesäure und die Stoffleitung bei höheren Pflanzen

Summary The effect of 2,3,5-triiodobenzoic acid (TIBA) on the translocation of various substances within etiolated pea plants was tested by applying the substances to different places on the decapitated plants and measuring the effect of the substances on the growth of lateral buds after placing a lanolin ring containing TIBA around the stem between the place of application of the substance and the buds. In control experiments the TIBA-ring was placed in such a way, that TIBA and the other substance reached the bud from opposite directions.TIBA blocked the basipetal translocation of indole-3-acetic acid, -4-chlorophenoxyisobutyric acid and -(1-naphthylmethylsulfid) propionic acid, it did not block the acropetal translocation of sucrose, potassium nitrate and indole-3-acetic acid. It did howevers block the acropetal translocation of native inhibitors (correlation inhibitors) extracted from pea plants. It is concluded that TIBA is a general blocker of the energy requiring translocation of many substances in plants. Moreover TIBA produces various different effects.Intensity of translocation of TIBA was equal in both directions, acropetal and basipetal. Application of TIBA to more distal points of the stem may cause greater effects because of a faster migration through younger tissues into the stem.Mit 2 Textabbildungen.     

On the question of β-indolyl-acetic acid synthesis from indole without a tryptophan intermediate

Summary Experiments with sterile grown maize coleoptiles were carried out to decide whether or not a biosynthetic path for -indolyl-acetic acid (IAA) from indole exists without tryptophan occurring as an intermediate. -Indolyl-acrylic acid as a tryptophan synthetase inhibitor significantly reduces the yield of [³H]tryptophan obtained from [³H]indole while the reduction in the [³H]IAA yield is considerably less pronounced. This, however, indicates only a non-linear relationship between the tryptophan concentration and the IAA yield and not the sought path. Moreover, double labelling combined with isotope competition methods in experiments with [³H]indole and L-[¹⁴C]serin show that all IAA synthesized from [³H]indole is produced on a path involving the synthesis of tryptophan as an intermediate.Abbreviation IAA -indolyl-acetc acid     

Nachweis und Chemische Trennung des Korrelationshemmstoffes und Seiner Hemmstoffvorstufe

Ohne Zusammenfassung     

Lanius senator in Brandenburg

Ohne Zusammenfassung     

Papierchromatographische Untersuchung der Hemmstoffe aus Erbsenpflanzen (einschliesslich des Korrelationshemmstoffes) und ihrer Wirkung in verschiedenen Biotests

Ohne ZusammenfassungMit 4 Textabbildungen     

Die Wirkung Des »Gibberellinantagonisten« 2-Chloräthyltrimethylammoniumchlorid (CCC) auf die Stecklingsbewurzelung Windender und nicht Windender Pflanzen

Summary Root initiation at cuttings is inhibited by application of gibberellin. CCC does not antagonize this inhibition. However, CCC stimulates root initiation at cuttings of three different species of twining plants known to be rich in endogenous gibberellin. CCC seems to be an antagonist for endogenous but not for exogenous gibberellin, which suggests that CCC influences gibberellin biosynthesis.     

Das Zusammenwirken von Wuchs- und Hemmstoffen bei der korrelativen Knospenhemmung

Ohne ZusammenfassungÜber den Inhalt dieser Veröffentlichung wurde auf der Botanikertagung in Münster am 8. September 1954 berichtet.