The polar transport of the natural auxins indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) has been described in Arabidopsis (Arabidopsis thaliana) hypocotyls using radioactive tracers. Because radioactive assays alone cannot distinguish IBA from its metabolites, the detected transport from applied [3H]IBA may have resulted from the transport of IBA metabolites, including IAA. To test...

Background The phytohormone auxin is critical for plant growth and orchestrates many developmental processes. Scope This review considers the complex array of mechanisms plants use to control auxin levels, the movement of auxin through the plant, the emerging view of auxin-signalling mechanisms, and several interactions between auxin and other phytohormones. Though many natural and synthetic co...

Auxin is the mobile signal controlling the rate of growth and specific aspects of the development of plants. It has been known for over a century that auxins act as the messenger linking plant development to specific environmental changes. An often overlooked aspect of how this is accomplished is the effect of the environment on metabolism of the major plant auxin, indole-3-acetic acid (IAA). W...

Sources of free indole-3-acetic acid (IAA) for the mesocotyl of intact etiolized maize ((Zea mays L.) seedlings are evaluated. The coleoptile unit, which includes the primary leaves and the coleoptilar node, is the main source of free IAA for the mesocotyl. The seed and the roots are not immediate sources of IAA supply. Dependence of the apical growing region of the mesocotyl on the coleoptile ...

The amount of indole-3-acetic acid (IAA) was measured in peach fruits by gas chromatography-mass spectrometry-selective ion monitoring using an isotope dilution assay with [(13)C(6)]IAA as an internal standard throughout the growing season. Ethylene evolution of the fruit was also measured. IAA levels were 25 nanograms per gram fresh weight, 18 days after anthesis. Both IAA levels and rates of ...

Auxin regulates many aspects of plant growth and development. Auxin is known to regulate gene expression through degradation of the AUX/IAA proteins, short-lived nuclear proteins that regulate gene transcription. The AUX/IAA proteins are degraded through the action of a ubiquitin protein ligase called SCF. Auxin promotes the interaction between AUX/IAA proteins and SCF in a soluble extract, sug...

Indole-3-acetic acid (IAA) is the most common plant hormone of the auxin class and is known to have many effects including cell proliferation enhancement and antioxidant property. However, no study has revealed its defensive effects against oxidative toxicity in human dental pulp stem cells (hDPSCs). In this study, we investigated the effects of IAA on hydrogen peroxide- (H2O2-) induced oxidati...

The plant hormone auxin plays pivotal roles in many aspects of plant growth and development. The auxin/indole-3-acetic acid (Aux/IAA) gene family encodes short-lived nuclear proteins acting on auxin perception and signaling, but the evolutionary history of this gene family remains to be elucidated. In this study, the Aux/IAA gene family in 17 plant species covering all major lineages of plants ...

By growth experiments in indoleacetic acid-1-(14)C (IAA), and determination of the (14)CO(2) evolved, it has been shown directly that polyphenols synergize IAA-induced growth by counteracting IAA decarboxylation. Sinapic and ferulic acids act like polyphenols. Endogenous polyphenols doubtless exert the same influence in intact plants. Monophenols stimulate the decarboxylation of IAA under condi...

The effect of xanthene dyes on the chemiluminescence from the aerobic indole-3-acetic acid (IAA) oxidation, catalyzed by horseradish peroxidase (HRP), was studied. The rate of IAA oxidation and dye destruction were controlled. It was found that the addition of dyes to the IAA/HRP/O2 system resulted in: (i) the appearance of emission in the region of dye fluorescence, (ii) an increase of the tot...