GIBBERELLIN PRODUCTION IN PEA SEEDS DEVELOPING IN EXCISED PODS: EFFECT OF GROWTH RETARDANT AMO-1618.

The gibberellin content of pea seeds developing in excised pea pods cultured on a medium containing the plant growth retardant AMO-1618 was reduced in comparison with pea seeds cultured on retardant-free medium. The reduction increased with increasing concentrations of AMO-1618. However, at the lowest concentration tested (5 milligrams per liter) the growth of the seeds was not affected whereas their gibberellin content was significantly reduced. In conjunction with earlier work on the effect of growth retardants on gibberellin biosynthesis in the fungus Fusarium moniliforme, these results indicate that AMO-1618 inhibits the biosynthesis of gibberellins in tissues of higher plants in much the same manner it does in Fusarium.