BIOLOGICAL-ACTIVITIES OF SOME IODINATED GIBBERELLINS

The biological activities of gibberellins** A1; A3, A4, and A7 were compared with lβ-iodo- gibberellinA1 1β-iodogibberellin A1 methyl ester and 1β-iodogibberellin A4in barley aleurone, lettuce hypocotyl and cucumber hypocotyl bioassays. Iodo GA1, methyl ester was inactive in all three assays. However, both iodo GA1 and iodo GA4 showed considerable activity in the lettuce hypocotyl and cucumber hypocotyl assays and moderate activity in the barley aleurone assay. These results are discussed in terms of structure-activity relationships of the GAs. Some possible uses of iodo GAs are indicated. © 1979, by the Agricultural Chemical Society of Japan.