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Root formation in vine (Vitis vinifera L. cv. Albariño) was accompanied by at first a rise and then a fall in total peroxidase (EC 1.11.1.7) activity in the explant. These variations ran parallel to similar changes in the amount of the three cathodic isoperoxidases detected, the most abundant of which, C2, also exhibited IAA oxidase activity. The anodic isoperoxidase bands detected were very weak and underwent no variation during rooting. Changes in the opposite direction (a fall followed by a rise) were shown by certain endogenous phenolics, including monoferuloyl, monocaffeoyl and mono-p-coumaroyl tartaric acids, some of which may act as auxin protectors. [ABSTRACT FROM AUTHOR]

Auxin protectors and IAA oxidase activity were comparatively analyzed in the upper and the lower parts of shoots of chestnut (Castanea sativa Mill.) cultivated in vitro with indolebutyric acid (IBA) pretreatment. Rhizogenesis of the shoots is accompanied by an increase in auxin protectors in the lower parts and by a decrease of these protectors in the upper parts. Besides, the IAA oxidase activity declines in the basal parts during the rooting process while it increases in the upper ones. These biochemical events would enhance the IAA level in the rooting region of the shoots. In untreated, non‐rooted cuttings, the IAA oxidase activity remains low in the upper parts and high in the basal parts of the shoots. The results thus indicate that the IBA treatment may control the endogenous auxin level of the cuttings, either through a direct regulation of the IAA oxidase system or more indirectly through the transport of auxin protectors. [ABSTRACT FROM AUTHOR]

The IAA‐oxidase activity in bean cuttings (Phaseolus vulgaris L. cv. Contender) treated with extracts from juvenile and adult chestnut (Castanea sativa Mill.) was studied in the light of the effect of the extracts on the rooting activity of some auxins. Extracts from adult chestnut increased IAA‐oxidase activity in bean cuttings. Extracts from juvenile chestnut inhibited IAA‐oxidase activity only slightly, but substantially reduced the IAA‐oxidase activity of bean cuttings pre‐treated with adult chestnut extracts. These findings provide evidence that there is a relationship between the IAA‐oxidase system and the effect of chestnut extracts on IAA‐induced rhizogenesis in bean cuttings. [ABSTRACT FROM AUTHOR]

The Avena cylinder test was used with Tweens at 3 different concentrations with and without the addition of varying concentrations of IAA. Tween 20 was a toxic substance for oat coleoptile sections at such concentration as 0.1%. Tween 40 gave erratic results and Tween 80 has practically no direct effect on cell elongation. An inhibitory effect continues to increase with increasing HLB values. The second object of this experiment was to ascertain whether cell elongation promoted by IAA would be enhanced by osmotic substances such as Tweens, as consequence of a specific modification in the permeability when the membranes are lipid in nature. The hypothesis was supported by the experimental work when 0.05 % Tweens were assayed although the inverse was also true, with concentrations of Tweens as low as 0.01%. Accordingly, evidence must be verified by further investigation. [ABSTRACT FROM AUTHOR]

A study of the cuttings of Salix atrocinerea Brot. was made by extraction with methanol, paper chromatography and Avena coleoptile straight growth test. In the acidic fraction, indole-3-acetic acid (IAA; about 15 μg per kg fresh weight) and p-hydroxybenzoic acid (PHB; about 850 μg per kg fresh weight) were isolated and identified. The growth activity of the different zones is explained by their content of these two compounds. The watersoluble residue, insoluble in ether, showed growth stimulating activity, which probably is due to a bound auxin (IAA-sugar); alkaline breakdown of this aqueous residue, giving PHB, vanillic and p-coumaric acids, suggests the presence (in the cuttings of Salix atrocinerea) of glycosides with aglycones similar to rhamnacine and scutellareine. [ABSTRACT FROM AUTHOR]