Curvature Occurrence and its Recovery in Cucumber Ovary and Fruit

Abstract

Cucumber ovaries began to show curvature when they reached a length of 4.5 mm, and at about 12 days before flowering. Ovary curvature seemed to occur subsequent to a temporary suppression of ovary growth. Thus, on a node with 2female flowers were developing, removing the tendril, 2nd female flower and lateral shoot of the node and the main stem above the node (hereafter described as neighboring organs), either alone or in combination, promoted ovary growth and consequently decreased ovary curvature of the 1st female flower. The earlier the removal, the greater its effects.
Fruit curvature also occurred after the suppression of early fruit growth. Thus, removing the neighboring organs alone or in combination late after flowering had no effect on fruit growth and curvature. As far as fruit curvature is concerned, fruit growth could be divided into 3 stages: (1) increasing, (2) maximizing, and (3) decreasing stage. The decrease in curvature occurred when fruit were left to grow on after the usual harvest time for fresh fruit. Curved fruit almost recovered their normal shape when they reached their final size.
The maximum curvature angle of fruit was found to occur just before harvest time, when fruit were 10-15cm in length, and 5-6 days after flowering. There was little correlation between the curvature angle and length of ovary at flowering, but there was a close correlation between the increase in curvature after flowering and the number of days from flowering to harvest.
These results suggest that curvature of ovaries and fruit is the result of a temporary suppression of growth during their rapid growth periods.