Plants growing in the same environment typically share ecophysiological characteristics enabling them to survive and reproduce when exposed to a common selection pressure. As such, seedlings establishing in temperate forest habitats cope with similar issues of low light availability and climate seasonality. We examined similarities in the germination syndromes in three shade-tolerant temperate forest herbs, Allium ursinum (Amaryllidaceae), Mercurialis perennis (Euphorbiaceae) and Dioscorea communis (Dioscoreaceae) with a distant phylogenetic affiliation. Seeds of M. perennis and A. ursinum are dispersed in spring and those of D. communis in autumn. Experiments on phenology of seed germination and seedling emergence in natural conditions revealed that seeds of all three species germinate in the following autumn. Seedlings do not emerge immediately but rather remain below the soil surface until late winter or early spring. Experiments in controlled laboratory conditions showed that seeds germinated best at intermediate autumn or spring temperatures (between 10 and 15°C) following a period at high summer temperatures (around 20°C). Seed germination of Allium ursinum is strongly photoinhibited, while moderate photoinhibition and no photoinhibition at all was observed in Dioscorea communis and Mercurialis perennis, respectively. Although seeds of all three species are endospermic at dispersal, no embryo growth prior to germination was observed. The cotyledons functioned as a haustorium, recuperating the nutrient reserves in the endosperm post-germination. It can be concluded that although phylogenetically unrelated, the three species studied show a remarkable similarity in germination and seedling emergence strategy that is commonly observed in plants adapted to growing in shady conditions.

中文翻译：

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三种系统发育较远的耐阴温带森林草本植物具有相似的种子萌发综合征

在相同环境中生长的植物通常具有共同的生态生理特征，使它们能够在面临共同选择压力时生存和繁殖。因此，在温带森林栖息地中建立的幼苗应对类似的光照不足和气候季节性问题。我们研究了三种耐阴温带森林草本植物，葱属（石蒜科）、多年生红皮草（大戟科）和薯蓣（薯蓣科）的发芽综合征的相似性，它们具有远距离的系统发育从属关系。M. perennis 和 A. ursinum 的种子在春季散播，而 D.communis 的种子则在秋季散播。自然条件下种子萌发和出苗物候的实验表明，这三个物种的种子都在接下来的秋天发芽。幼苗不会立即出苗，而是一直留在土壤表面以下，直到晚冬或早春。在受控实验室条件下进行的实验表明，在夏季高温（约 20°C）一段时间之后，种子在秋季或春季中期温度（10 至 15°C）发芽最佳。Allium ursinum 的种子萌发受到强烈的光抑制，而在 Dioscorea community 和 Mercurialis perennis 中分别观察到中度光抑制和完全没有光抑制。尽管所有三个物种的种子在传播时都是胚乳，但未观察到萌发前的胚胎生长。子叶起到吸器的作用，在发芽后恢复胚乳中的营养储备。可以得出结论，虽然在系统发育上无关，