The Role of Plant Hormones in Fruit Development

Citation

Nitsch, Jean Paul (1951) The Role of Plant Hormones in Fruit Development. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/G2GR-7342. https://resolver.caltech.edu/CaltechTHESIS:04072017-091032690

Abstract

Starting with the initiation of the ovary primordium, a coordinate study of the hormonal relationships in fruit growth has been attempted with fruits attached on the plants and also by the new technique of in vitro culture. Several phases were recognized in the ontogeny of a fruit. To be able to initiate flower primordia the plant has first to enter a reproductive condition. The formation of ovary primordia was studied in some cucurbits, in which it was found that the environment profoundly influences the apparition of female vs. male flowers. It has been concluded that these environmental factors regulate the length of successive phases in cucurbit flowering. Once initiated, the ovary enlarges regularly, mainly by cell division until anthesis. If pollination is prevented, ovary growth ceases at this stage, and there is indication that the auxin level of the flower decreases. The ovary then shrinks or drops off the plant. Flower abscission is prevented and growth is stimulated by the pollen which performs these effects mainly by increasing the auxin level of the ovary, partly at least through an enzymatic mechanism. After fertilization fruit growth is controlled by the developing seeds which release large quantities of auxin, the latter apparently manufactured in the endosperm. Thus, auxin has been found to affect any stage of fruit development.

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