Endogenous gibberellins in foliage of tomato (Lycopersicon esculentum)

Endogenous gibberellins (GAs) from the leaves and shoot tips of 13-14 days old tomato transplants (Lycopersicon esculentum Mill.) grown in solarised or non-solarised soil were analysed by GC-mass spectrometry. Full- scan mass spectra and Kovats retention indices revealed in plants from both soils the presence of GA₁, GA₃, GA₃-isolactone, GA₄, GA₈, GA₁₉, GA₂₀, GA₂₉, GA₃₄ and GA₅₁. Further analyses by GC-SIM indicated the presence of GA₄₄ and GA₅₃ in the tomato foliage. An isotope-dilution analysis revealed that most of the GA₃-isolactone was a methodological artefact. Our results provide the first conclusive identification of most members of the early-13-hydroxylation biosynthetic pathway in vegetative tomato tissues. In addition, the presence of GA₄, GA₃₄ and GA₅₁ which were not reported previously in the tomato, indicates that the early-non- 3,13-hydroxylation biosynthetic pathway is a so active. Three potentially active GAs GA₁, GA₃ and GA₄, were identified in tomato foliage, all of which may play an important role in regulating growth in this species.