PREMISE Lace plant (Aponogeton madagascariensis) leaves are remodeled via developmental programmed cell death (PCD) to produce perforations located equidistantly between longitudinal and transverse veins. Auxin has been implicated in other developmental PCD processes in plants; however, the role of auxin in perforation formation in lace plant is unknown. Here the role of auxin in developmental PCD in lace plant was studied using two auxin inhibitors N-1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, and auxinole, a potent auxin antagonist. METHODS Sterile cultures of lace plants were propagated and treated with NPA or auxinole. Leaf length, leaf width, and number of perforations were then analyzed. Vein patterning and perforation area were further examined in NPA-treated plants. Downstream PCD transduction events were investigated via spectrophotometric assays, histochemical staining, and immuno-probing. RESULTS Lace plants treated with NPA or auxinole produced leaves with fewer perforations compared to their respective controls. Although NPA treatment was insufficient to completely alter vein patterning, NPA-treated leaves did have significantly more atypical areoles compared to control leaves. Events involved in perforation formation in lace plant leaves were altered following treatment with NPA, including anthocyanin production, reactive oxygen species (ROS) accumulation, and the release of mitochondrial cytochrome c. CONCLUSIONS Our results indicated that inhibition of auxin signaling disrupts several downstream features of the lace plant PCD signaling cascade and results in fewer or no perforations. Therefore, we concluded that auxin signaling is important for developmentally regulated PCD in lace plant leaves.

中文翻译：

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生长素在花边植物发育调控程序性细胞死亡中的作用

PREMISE 花边植物（Aponogeton madagascariensis）的叶子通过发育程序性细胞死亡（PCD）进行改造，以产生等距位于纵向和横向静脉之间的穿孔。生长素与植物的其他发育 PCD 过程有关。然而，生长素在花边植物穿孔形成中的作用尚不清楚。在这里，使用两种植物生长素抑制剂 N-1-萘基邻苯二甲酸 (NPA)（一种植物生长素转运抑制剂）和植物生长素醇（一种有效的植物生长素拮抗剂）研究了植物生长素在花边植物发育 PCD 中的作用。方法 将花边植物的不育培养物繁殖并用NPA 或生长素醇处理。然后分析叶长、叶宽和穿孔数。在 NPA 处理的植物中进一步检查了静脉图案和穿孔区域。通过分光光度法、组织化学染色和免疫探测研究了下游 PCD 转导事件。结果 与它们各自的对照相比，用 NPA 或 auxinole 处理的花边植物产生的叶子具有更少的穿孔。尽管 NPA 处理不足以完全改变静脉图案，但与对照叶子相比，NPA 处理的叶子确实具有明显更多的非典型乳晕。在用 NPA 处理后，与花边植物叶片穿孔形成有关的事件发生了改变，包括花青素的产生、活性氧 (ROS) 的积累和线粒体细胞色素 c 的释放。结论 我们的结果表明，生长素信号传导的抑制破坏了花边植物 PCD 信号级联的几个下游特征，并导致较少或没有穿孔。所以，