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Effect of Photoperiod on Metabolism of [ 3 H] Gibberellins A 1 , 3- epi -A 1 , and A 20 in Agrostemma githago L.

1982; Oxford University Press; Volume: 69; Issue: 3 Linguagem: Inglês

10.1104/pp.69.3.660

1532-2548

M. G. K. Jones, Jan A. D. Zeevaart,

Leaf Properties and Growth Measurement

To determine whether daylength influences the rate of metabolism of gibberellins (GAs) in the long-day (LD) rosette plant Agrostemma githago L., [3H]GA20 and [3H]GA1 were applied under short day (SD) and LD. Both were metabolized faster under LD than under SD. [3H]GA20 was metabolized to a compound chromatographically identical to 3-epi-GA1. [3H]GA1 was metabolized to two acidic compounds, the major metabolite having chromatographic properties similar to, but not identical with GA8. [3H]3-epi-GA1 applied to plants under LD was metabolized much more slowly than was [3H]GA1, and formed a very polar metabolite which did not partition into ethyl acetate at pH 2.5. Very polar metabolites were also formed after the feeds of [3H]GA20 and [3H]GA1. It was not possible to characterize these very polar compounds further because of their apparent instability. The results obtained suggest that in Agrostemma GA20 is the precursor of 3-epi-GA1, but there is at present no evidence indicating the precursor of GA1.