Abstract
Watermelon fruits were enclosed within 20 cm cube boxes to mechanically restrict the enlargement and changes in sugar concentration and cell size were investigated. Covering with a cube box from 15 to 45 days after pollination significantly restricted fruit enlargement of the watermelon. This mechanical restriction of fruit enlargement resulted in decreased sucrose accumulation at the central portion of the fruits, in contrast to increased accumulation of this element at the outer portion. Cell size in the fruits also varied according to the mechanical restriction. At the central portion of the fruits, a larger number of small cells derived from vascular bundles was detected in the restricted fruits. Conversely, meristematic cells in the outer portion increased in size due to the mechanical restriction.
