College of Life Sciences, Capital Normal University, North Xisanhuan 105, Beijing, 100048, China.
Biol Trace Elem Res. 2012 Apr;146(1):86-93. doi: 10.1007/s12011-011-9212-9. Epub 2011 Sep 24.
Lead is a widespread pollutant and has been reported to inhibit pollen tube development, but the mechanism of toxicity involved remains unclear. Here, we report that lead stress significantly prevented Picea wilsonii pollen germination and tube growth and also dramatically altered the tube morphology in a concentration-dependent manner. Fluorescence labeling with JIM 5 (anti-acidic pectin antibody) and Calcofluor white revealed the lead-induced decline of acidic pectin and cellulose, especially in the subapical region. Decolorized aniline blue staining showed the marked accumulation of callose in the apical and subapical regions of lead-treated tubes. Fluorescence labeling with Alexa Fluor 568 phalloidin and anti-tubulin antibody revealed that the distribution of the cytoskeleton in P. wilsonii pollen grains and tubes were developmentally regulated and that lead disturbed the cytoskeleton organization, especially in the shank of the pollen tubes. Taken together, our experiments revealed a link between the dynamics of cytoskeleton organization and the process of P. wilsonii pollen tube development and also indicated that lead disturbed the cytoskeleton assembly and, consequently, cell wall construction. These findings provide new insights into the mechanism of lead toxicity in the tip growth of pollen tubes.
铅是一种广泛存在的污染物，已被报道能抑制花粉管的发育，但其中涉及的毒性机制仍不清楚。在这里，我们报告说，铅胁迫显著阻止了云杉花粉的萌发和管的生长，并且以浓度依赖的方式显著改变了管的形态。用 JIM5（抗酸性果胶抗体）和 Calcofluor white 进行荧光标记显示，铅诱导的酸性果胶和纤维素下降，特别是在亚顶端区域。褪色苯胺蓝染色显示，在铅处理的管的顶端和亚顶端区域，胼胝质的积累明显。用 Alexa Fluor 568 鬼笔环肽和抗微管蛋白抗体进行荧光标记显示，云杉花粉粒和管中的细胞骨架的分布是发育调控的，而铅扰乱了细胞骨架组织，特别是在花粉管的柄部。总之，我们的实验揭示了细胞骨架组织动力学与云杉花粉管发育过程之间的联系，并表明铅扰乱了细胞骨架的组装，从而影响了细胞壁的构建。这些发现为花粉管顶端生长中铅毒性的机制提供了新的见解。
