| Abstract: | The sex expression of Lagenaria siceraria can be modified by phytohormones. This modification is related to "a certain bisexual stage" during floral bud differentiation. ACC (ethylene precursor) and STS (ethylene antagonist) can change the direction of sex differentiation of the floral buds in vitro. STS induces maleness by means of inhibiting ethylene action, directly promoting the development of the primordia of stamens, and then suppressing that of pistils. Hence, it can be deduced that ethylene induces femaleness by directly suppressing the development of the primordia of stamens and then promoting that of pistils. Such a regulation of the development of sexual organs is due to a change in the direction of assimilates to the pistils by ACC and to the stamens by STS. Therefore, ethylene induces femaleness by first limiting the sink strength of the stamens and then increasing that of the pistils. |
