Neck shrivel in European plum: Mechanisms and causes

欧洲李子的颈部枯萎：机制和原因

• 批准号: 436553869
• 负责人: Professor Dr. Moritz Knoche
• 金额: --
• 依托单位: Institut für Gartenbauliche Produktionssysteme
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/436553869?language=en
• 关键词: Neck; shrivel; European; plum; Mechanisms

Neck shrivel is a physiological disorder of European plum fruit characterized by a shriveled pedicel-end and a turgescent stylar-end. It develops pre-harvest and continues postharvest. Affected fruit are perceived as poor quality, so are of low commercial value. Cultivar (genetic) differences exist in susceptibility to neck shrivel. Little is known of the mechanistic basis of neck shrivel. Increased transpiration through microcracks in the cuticle of the stem-end contributes to neck shrivel. However, at present it is not known whether this is the only reason for neck shrivel. Also, the mechanism of microcrack formation in the stem end and the absence thereof in the stylar end of the symmetric plum fruit is unknown. Empirical observations suggest water relations may play a role. Two hypotheses may be thought of that account for neck shrivel: Hypothesis 1 – The stem end, but not the stylar end has a negative water balance in symptomatic fruit. There is no such difference in non-symptomatic fruit. Hypothesis 2 – A gradient in osmotic potential from the stem end (less negative) to the stylar end (more negative) causes a redistribution of water from the stem end to the stylar end. The objective is to test the validity of these hypotheses. We will focus on the following items: (1) Why do microcracks, that are the primary reason for increased transpiration of the stem end, form at the stem end, but at not the stylar end although the fruit is largely symmetric (hypothesis 1 – negative water balance due to increased transpiration)(2) Differential vascular water transport in the xylem that feeds the stylar end of susceptible cultivars, but not or to a lesser extent the stem end (hypothesis 1 – negative water balance due to reduced vascular inflow), and (3) Gradients in water potential, osmotic potential and turgor between stem end and stylar end in susceptible cultivars (hypothesis 2 – internal redistribution due to gradients in osmotic potential). Understanding the mechanism of neck shrivel is a prerequisite for (1) breeding new, less-susceptible plum cultivars and (2) developing cultural measures that might decrease the incidence of neck shrivel. We expect the information generated to be applicable to many other fleshy fruit crop species, from cool temperate regions to the tropics.

颈萎是欧洲李子果实的一种生理失调，其特征是花梗末端萎缩和花柱末端肿胀。它在收获前发展，并在收获后继续发展。受影响的水果被认为质量差，因此商业价值低。品种（遗传）对颈萎病的易感性存在差异。人们对颈部萎缩的机制基础知之甚少。通过茎端角质层的微裂缝增加的蒸腾作用有助于颈部萎缩。然而，目前尚不清楚这是否是颈部萎缩的唯一原因。此外，在对称李子果实的茎端微裂纹的形成机制和在花柱端微裂纹的不存在是未知的。经验观察表明，水的关系可能起作用。有两种假说可以用来解释颈干萎缩：假说1 -在有症状的果实中，茎端而非花柱端具有负水分平衡。在无症状的水果中没有这种差异。假设2 -渗透电位从茎端（负电位较小）到柱头端（负电位较大）的梯度导致水从茎端重新分配到柱头端。目的是检验这些假设的有效性。重点抓好以下几方面工作：(1)为什么微裂隙,蒸腾上升的主要原因是阀杆,杆一端,但不是花柱尽头虽然水果主要是对称的(假设1 - - - - - - -水平衡由于蒸腾作用)的增加(2)微分血管水运在木质部为花柱易感品种,但不是结束或一定程度上遏制(假设1 - - - - - - -水平衡由于减少血管流入),(3)敏感品种茎端和花柱端水势、渗透势和膨胀的梯度（假设2 -渗透势梯度引起的内部再分配）。了解颈萎病的发病机制是(1)选育低易感李子新品种和(2)制定降低颈萎病发生的栽培措施的先决条件。我们希望所产生的信息适用于许多其他肉质水果作物物种，从凉爽的温带地区到热带。