The Relation Between Seed and Fruit Development in the Peach (Prunus persica L.)

The ontogeny of the peach seed and its organs correlates well with the stages of growth of the pericarp of peach fruit. The initial stages of rapid f.wt (FW I) and d.wt (DW I) increase coincide with the period of rapid f.wt increase of the whole seed and rapid size increase of the endosperm respectively. The period of slow f.wt increase of the fruit (FW II) coincides with the period of rapid size increase of the embryo. The seed and pericarp compete strongly for assimilates throughout fruit development and the seed is the weaker competitor. There is no period however when the growth of the seed or one of its organs inhibits the sink strength of the pericarp to allow the seed to develop. The data presented indicate that the periods of high nutrient demand (DW I and DW III) are created in the pericarp in response to a stimulatory signal from the seed and the period of low nutrient demand (DW II) results from the absence of this signal after the endosperm reaches full size.