Detached, wetted strawberries take up substantial water in the calyx region

Abstract

In strawberry, surface disorders like ‘water soaking’, ‘cracking’ and ‘shrivel’ impair fruit quality of this high value crop. Water movement through the fruit surface is implicated a role in these disorders. The objective was to identify the pathways of water uptake and water loss (transpiration) and to identify factors affecting these flows. Water movement was quantified gravimetrically in detached fruit. Cumulative transpiration and uptake increased linearly with time. During ripening, fruit osmotic potential and water potential became slightly more negative. Rates of transpiration and water uptake and their corresponding permeances were constant during early ripening but increased as the fruit turned red. The permeance for osmotic water uptake was more than 10-times that for transpiration. Sealing selected regions of the fruit surface with silicone rubber allowed identification of the petal and staminal abscission zones in the calyx region and cuticular microcracks of the calyx region and receptacle as high flux pathways particularly for water uptake (osmotic). These results were confirmed by acridine orange infiltration and fluorescence microscopy. Increasing the relative humidity (RH) decreased the rate of transpiration, while increasing temperature increased both transpiration and water uptake. There was no effect of storing fruit (2 °C, ~ 80% RH) for up to 10 days. Our results identify petal and staminal abscission zones and cuticular microcracks as high flux pathways for water uptake.