Heterophylly is the development of different leaf forms in a single plant depending on the environmental conditions. It is often observed in amphibious aquatic plants that can grow under both aerial and submerged conditions. Although heterophylly is well recognized in aquatic plants, the associated developmental mechanisms and the molecular basis remain unclear. To clarify these underlying developmental and molecular mechanisms, we analyzed heterophyllous leaf formation in an aquatic plant, Callitriche palustris. Morphological analyses revealed extensive cell elongation and the rearrangement of cortical microtubules in the elongated submerged leaves of C. palustris. Our observations also suggested that gibberellin, ethylene, and abscisic acid all regulate the formation of submerged leaves. However, the perturbation of one or more of the hormones was insufficient to induce the formation of submerged leaves under aerial conditions. Finally, we analyzed gene expression changes during aerial and submerged leaf development and narrowed down the candidate genes controlling heterophylly via transcriptomic comparisons, including a comparison with a closely related terrestrial species. We discovered that the molecular mechanism regulating heterophylly in C. palustris is associated with hormonal changes and diverse transcription factor gene expression profiles, suggesting differences from the corresponding mechanisms in previously investigated amphibious plants.

中文翻译：

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两栖植物Calliriche palustris L中异叶植物独特分子框架的鉴定

异叶植物是根据环境条件在单个植物中发育不同的叶子形式。它经常在可以在空中和水下条件下生长的两栖水生植物中观察到。虽然异生植物在水生植物中得到广泛认可，但相关的发育机制和分子基础仍不清楚。为了阐明这些潜在的发育和分子机制，我们分析了水生植物 Callitriche palustris 中的异叶叶形成。形态学分析揭示了广泛的细胞伸长和 C. palustris 伸长的沉没叶片中皮层微管的重排。我们的观察还表明赤霉素、乙烯和脱落酸都调节沉叶的形成。然而，在空气条件下，一种或多种激素的扰动不足以诱导沉水叶片的形成。最后，我们分析了空中和水下叶片发育过程中的基因表达变化，并通过转录组比较缩小了控制异质性的候选基因，包括与密切相关的陆地物种的比较。我们发现在 C. palustris 中调节异叶植物的分子机制与激素变化和多种转录因子基因表达谱有关，这表明与先前研究的两栖植物中的相应机制存在差异。我们分析了空中和水下叶片发育过程中的基因表达变化，并通过转录组比较缩小了控制异质性的候选基因，包括与密切相关的陆地物种的比较。我们发现在 C. palustris 中调节异叶植物的分子机制与激素变化和多种转录因子基因表达谱有关，这表明与先前研究的两栖植物中的相应机制存在差异。我们分析了空中和水下叶片发育过程中的基因表达变化，并通过转录组比较缩小了控制异质性的候选基因，包括与密切相关的陆地物种的比较。我们发现在 C. palustris 中调节异叶植物的分子机制与激素变化和多种转录因子基因表达谱有关，这表明与先前研究的两栖植物中的相应机制存在差异。