Postharvest deformation of cucumber fruit associated with water movement and cell wall degradation

Changes in water content and cell wall polysaccharides associated with postharvest deformation of cucumber fruit (Cucumis sativus L. ‘Natsu-suzumi’) were investigated.
When 20 cm long fruit were stored at 22°C and 90% RH, seed development was observed in the distal portion and the fruit circumference increased by 30% on day 12, whereas the fruit circumference of the middle portion decreased continuously until day 19. The increase in the fruit diameter of the swollen portion was mainly due to swelling of the placenta, whereas the decrease in that at the shrunken portion was due to shrinkage of the mesocarp.
In the shrunken area, intercellular air-spaces increased in the mesocarp while no distinct change was found in the placenta.
Enlargement of the cell size was observed only in the placenta of the swollen portion.
In the swollen portion, both the covalently-bound pectin polymers and hemicelluloses decreased among cell wall polysaccharides.
Non-pollinated fruit also deformed during storage, but the deformed portions of non-pollinated fruit differed from those of pollinated fruit.
Our findings suggest that postharvest swelling of cucumber fruit occurs due to the movement of water from the mesocarp into the placental cells in relation to cell wall loosening.

VIII International Postharvest Symposium: Enhancing Supply Chain and Consumer Benefits – Ethical and Technological Issues

T. Nishizawa, T. Okada, Y. Suzuki, Y. Motomura, T. Aikawa

Cucumis sativus, air space, mesocarp, placenta, pollination

https://doi.org/10.17660/ActaHortic.2018.1194.173