Course of Pollen Tube Growth in Carica papaya and Cucurbita spp

Abstract

IN a recent paper, Gustafson1 states with reference to pumpkin and crookneck summer squash (Cucurbita spp.) that the “application of pollen to one side of the ovary did not limit the development of the seeds to that side, and the seed distribution was quite uniform even when as much as five-sixths of the stigma had been removed.… It was expected, however, that the seeds might develop only on that side of the ovary where the pollen was applied and the side without seeds would be apertrophied”. Work on the course of pollen tube growth in Carica papaya, carried on by us in Florida in 1936 as part of a Bankhead-Jones project, has a bearing on this subject. The Caricaceae are related not distantly to the Cucurbitaceae, but the former have superior ovaries in contrast to inferior ovaries in the latter. However, the general place of entry of the pollen tubes in relation to the extent and display of the placental surface is similar.