Water-soaking and cracking in strawberry: Mechanism and causes

成熟的草莓果实表现出非常有限的雨量。首先，湿润的皮肤很快就会显示出被水浸泡的迹象，其次，紧随其后的是下面的肉组织逐渐分解。这两个问题在干燥后都是完全不可逆的。保护性耕作是目前唯一可以可靠地限制这些问题的措施，但这大大增加了生产成本。第三个问题是果实成熟后迅速变软--无论是收获前还是收获后。这三个因素决定了销售点的水果质量。在这里，我们开始研究这三种现象都与果实水分关系直接或间接相关的假设。我们的目标是确定水浸泡和果肉细胞破裂的机制基础。我们将集中于：(1)草莓果皮的细胞学特征--有和没有雨水损害的迹象，(2)测定水分通过果柄进入果实的速率，(3)通过果实表面的水分损失(蒸腾)的速率，以及(4)确定钙和膨胀剂对：(I)果实坚硬，(Ii)细胞壁膨胀，(Iii)组织断裂模式和(Iv)对雨水损害的敏感性的影响。我们希望获得所需的基础信息，以了解草莓果实的生理及其品质，并确定这些是如何受到水果水分关系的影响。这些信息是制定减轻雨水损害(浸水、果肉腐烂)的战略所必需的，并通过改变生产方法和水果育种来帮助维持水果的坚固性。

Mature fruits of strawberry show very limited rainfastness. First, their wetted skins soon show signs of water-soaking and, second, this is quickly followed by a progressive disintegration of the underlying flesh tissues. Neither problem is at all reversible upon drying. Protected cultivation is the only measure currently available that reliably limits these problems but this significantly increases the cost of production. A third problem is the rapid softening of the fruit once maturity is reached – both pre- and post-harvest. These three factors dominate in the determination of fruit quality at point of sale. Here, we set out to investigate the hypothesis that all three phenomena are directly or indirectly related to fruit water relations. Our objectives are to identify the mechanistic bases of water soaking and cell rupture in the flesh. We will focus on: (1) characterising the cytology of the skins of strawberry fruit - with and without signs of rain damage, (2) determining the rate of water transport into the fruit through the stalk, (3) quantifying the rates of fruit water loss (transpiration) through the fruit surface and (4) establishing the effects of calcium and turgor on: (i) fruit firmness, (ii) cell-wall swelling, (iii) tissue fracture mode and (iv) susceptibility to rain damage. We expect to obtain the underpinning information required to understand the physiology of strawberry fruits and their quality and to determine how these are affected by fruit water relations. This information is required to develop strategies to mitigate rain damage (water soaking, flesh disintegration) and to help maintain fruit firmness via both altered production methods and fruit breeding.