Endogenous gibberellin levels and senescence in Taraxacum officinale.

The level of endogenous gibberellins (GAs) in leaf tissue of Taraxacum officinale was high during leaf growth and expansion but declined progressively during leaf senescence. In the chromatographic system used, most of the GA from Taraxacum leaves moves with the Rf of GA3. However, several other GAs were also effective in retarding senescence in Taraxacum leaves. It is concluded that ageing of dandelion leaves is associated with a deficiency of endogenous GA.