Abstract Aluminum (Al) is known the most abundant metal in the Earth’s crust which is a major problem limiting crop production and yield throughout the world. Al could inhibit pollen tube elongation, however the mechanism is largely unknown. The aim of this study was to investigate the influence of Al toxicity on Malus domestica pollen tube growth and possible cytological mechanism. The results showed that Al inhibited pollen germination and tube growth in a concentration dependent manner. An non-invasive ion-selective electrode technique together with fluorescent labeling indicated that Al toxicity decreased pollen tube apex calcium influx and disrupted [Ca2+]c gradient. Al toxicity also altered actin filament orientation. Results from immuno-localization and fluorescence labeling indicated that Al toxicity affected the accumulation and distribution of callose, acid pectins, esterified pectins and arabinogalactan proteins in pollen tubes, which were supported by Fourier-transform infrared analysis. In a word, Al induced a series of the cellular toxic changes concerning calcium influx, [Ca2+]c gradient, actin and cell wall components. Based on the information provided in this article, it is concluded that Al toxicity inhibits apical growth of pollen tubes by changing calcium influx and [Ca2+]c and cell wall components.

中文翻译：

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苹果（Malusdomesica）中铝毒诱导的花粉管生长抑制是通过中断钙动力学和细胞壁成分的修饰来介导的

摘要 铝 (Al) 是已知地壳中含量最丰富的金属，是限制全世界作物生产和产量的主要问题。铝可以抑制花粉管伸长，但其机制在很大程度上是未知的。本研究的目的是研究铝毒性对苹果花粉管生长的影响和可能的细胞学机制。结果表明，铝以浓度依赖性方式抑制花粉萌发和花粉管生长。非侵入性离子选择性电极技术与荧光标记一起表明，Al 毒性降低了花粉管顶端钙的流入并破坏了 [Ca2+]c 梯度。Al 毒性也改变了肌动蛋白丝的方向。免疫定位和荧光标记的结果表明，Al 毒性影响了花粉管中胼胝质、酸性果胶、酯化果胶和阿拉伯半乳聚糖蛋白的积累和分布，傅里叶变换红外分析证实了这一点。总之，铝诱导了一系列关于钙流入、[Ca2+]c 梯度、肌动蛋白和细胞壁成分的细胞毒性变化。根据本文提供的信息，可以得出结论，Al 毒性通过改变钙内流和 [Ca2+]c 和细胞壁成分来抑制花粉管的顶端生长。[Ca2+]c 梯度、肌动蛋白和细胞壁成分。根据本文提供的信息，可以得出结论，Al 毒性通过改变钙内流和 [Ca2+]c 和细胞壁成分来抑制花粉管的顶端生长。[Ca2+]c 梯度、肌动蛋白和细胞壁成分。根据本文提供的信息，可以得出结论，Al 毒性通过改变钙内流和 [Ca2+]c 和细胞壁成分来抑制花粉管的顶端生长。