Early Fruit Development in the Watermelon: Anatomical Comparison of Pollinated, Auxin-induced Parthenocarpic and Unpollinated Fruits

Publisher Website
Google Scholar
Abstract
The anatomy of pollinated, auxin-induced parthenocarpic and unpollinated watermelon fruits was observed for nine days after flowering. Parthenocarpic fruits were larger and had higher fresh weight and percentage water than pollinated fruits at day 1 but the positions were reversed by day 9. Unpollinated fruits did not increase in size after day 3. Pericarp cells were small, of regular shape and showed no obvious change with either time or treatment. Cell number increased in the pollinated and parthenocarpic but not in the unpollinated fruits. Cells divided in the flesh of the parthenocarpic but not of the pollinated fruits which increased in size by cell enlargement only. Starch, present in the cells of the flesh and placenta at day 0 was absent from the unpollinated fruits at day 6. Ovules grew in both pollinated and parthenocarpic fruits largely due to cell division in the nucellus and integuments; the pollinated ovules were larger than the parthenocarpic throughout. Embryo and endosperm development occurred in the pollinated but not in the parthenocarpic ovules. Starch was present throughout the nine-day period in the integuments of the pollinated and parthenocarpic ovules but was lost from the integuments of the unpollinated ovules by day 6. Pollinated and parthenocarpic ovules contributed increasingly to fruit dry weight over the nine-day period. It is suggested that the ovule tissues, in particular the nucellus and integument may exert control over early development in both pollinated and parthenocarpic fruits.

This publication has 1 reference indexed in Scilit: