Nucleic Acid Metabolism During Early Development of Pollinated and Auxin-induced Parthenocarpic Watermelon Fruits

Following pollination or induction of parthenocarpy by NAA¹treatment watermelon ovaries synthesize large quantities ofRNA. Hormone-treated ovaries increase their rate of RNA synthesisover untreated controls by 6 h after treatment whereas pollinatedovaries do so by 24 h. The lag period with pollinated ovarieshas been related to the growth of pollen tubes toward the ovulesand it is suggested that auxin secretion by the growing pollentubes may be the stimulus for increased RNA synthesis. Evidenceis presented that the cells in the flesh of developing ovariesbecome polyploid as they enlarge.