Treatment with auxin often causes parthenocarpic development in several plant species [for review, see: [12]]. However, in some species and/or varieties, to efficiently sustain fruit growth, the hormonal treatment of the flowers must be repeated [13]. The finding that DefH9-iaaM mRNA is also present during later stages of fruit development is consistent with the interpretation that in DefH9-iaaM parthenocarpic plants, the placenta, the ovules, and the tissues derived therefrom are a source of auxin during the whole growth of the fruit. As a consequence, they efficiently sustain fruit growth.