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Updated: May 3, 2026

Visualizing Cellular Gibberellin Levels Using the nlsGPS1 Förster Resonance Energy Transfer (FRET) Biosensor
Published on: January 12, 2019
Diffusible gibberellins and phototropism in Helianthus annuus
1Department of Biological Sciences, University of Exeter, Exeter, Devon, UK.
Abstract:
Endogenous gibberellins were obtained in agar from the lower cut surface of upright sunflower shoot-tips. Exposure to unilateral light of the tips standing on agar, with the lower cut ends bisected by a vertical glass barrier at right angles to incident light, resulted in approximately 8 times the quantity of gibberellins moving into the agar below the shaded side than into the agar below the illuminated side. These results are similar to those reported earlier for gibberellins and geotropism in sunflower shoots, and suggest than the development of both light-and gravity-induced growth curvatures involve an asymmetry in gibberellin distribution across elongating internodes.
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