Determination of Relative Auxin Content in Hermaphrodite and Andromonoecious Cucumis sativus L.

Abstract

The possibility that different sex types of C sativus (cucumber) vary in the amount of endogenous auxin and that this difference in auxin content is causally related to sex expression was tested. The procedure of auxin extraction resulted in an over 60% efficiency of IAA-C14 recovery from plant material and negligible conversion of tryptophan-C14 to IAA-C14. The uppermost section of hermaphrodite cucumber shoots was shown to be higher in auxin content than the parallel section of andromonoecious plants. In lower sections of the shoot the difference as well as the absolute amount of auxin decreased. Because sex determination of the floral buds in hermaphrodite plants takes place closer to the tip than in andromonoecious plants, endogenous auxin content may regulate sex expression in cucumber.