Water relations in detached sweet cherry fruit and their role in the postharvest disorder 'orange peel' (shrivelling)

果皮皱缩和果梗褐变是影响甜樱桃果实采后外观的病症。橙皮紊乱的特征是果实果皮局部凹陷，覆盖越来越多的部分，最终覆盖成熟甜樱桃果实采后的整个表面。出现橘皮症状的水果被市场拒之门外并被淘汰。由于只有高品质的樱桃才需要进行采后处理(分级、水冷、MAP、储藏、国际全球运输)，由此造成的经济损失是巨大的。人们对橙皮紊乱的机制基础知之甚少。与凹坑不同，橘皮不是由机械冲击造成的。间接证据表明，柑橘果皮失调与S的果实水分关系有关。我们建议的目标是(1)描述甜樱桃果实采后橙皮紊乱的特征并确定影响这种紊乱的因素，(2)量化水分通过花梗和果实表面以及果实与花梗之间运输的流动速率、流量、驱动力和渗透率，以及(3)识别和定位果实内的任何水势梯度和运输阻力，这些可能解释径向水分从果皮到底层薄壁组织细胞层的运输。产生的数据不仅将揭开橙皮失调的机理基础，而且还将为研究肉质水果复杂的水分关系提供新的见解。这些水果的独特之处在于，它们的高碳水化合物浓度会产生显著的渗透压。由于其柔软的质地，这些渗透压显然不被坚硬的细胞壁所控制，而坚硬的细胞壁需要包含由此产生的高膨胀压力。橙色果皮紊乱和可能的果梗褐变是否也与这些现象有关，将在项目过程中确定。

Shrivelling (orange peel) and pedicel browning are disorders that impair the appearance of sweet cherry fruit postharvest. The orange peel disorder is characterized by localized depressions in the fruit skin that cover increasing portions and ultimately the entire surface of mature sweet cherry fruit postharvest. Fruit exhibiting orange peel symptoms are rejected by the market and culled. Since only high quality cherries is subjected to postharvest procedures (grading, hydrocooling, MAP, storage, international world wide shipping), the resulting economic loss is significant. Little is known about the mechanistic basis of the orange peel disorder. Unlike pitting, orange peel is not caused by mechanical impact. Indirect evidence suggests that the orange peel disorder is linked to the fruit s water relations. The objectives of our proposal are to (1) characterize the postharvest orange peel disorder in sweet cherry fruit and identify factors affecting the disorder, (2) quantify flow rates, fluxes, driving forces and permeabilities for water transport through the surface of pedicel and fruit and for the transport between fruit and pedicel and (3) identify and locate any water potential gradients and transport resistances within the fruit, that might account for radial water transport from the fruit skin into cell layers of the underlying parenchyma. The data generated will not only unravel the mechanistic basis of the orange peel disorder, but they will also provide new insights in the complex water relations of fleshy fruit. These fruit are unique in that their high carbohydrate concentrations generate significant osmotic pressures. Because of their soft texture these osmotic pressures apparently are not contained by rigid cell walls that would be required to contain the resulting high turgor pressures. Whether the orange peel disorder and possibly the browning of pedicels is also related to these phenomena, will be identified in the course of the project.