Plant species of the intermediate life strategy type are characteristic for species-rich grasslands, which are sensitive to changes in the level of disturbance. Germination and early establishment of seedlings is expected to be the most crucial stage, limiting the successful colonization of appropriate sites. Valeriana dioica is a typical plant of calcareous fens, which are dependent on regular suppression of strong competitors by means of moderate land use. It is endangered in many parts of Central Europe, including Lower Austria. We studied the effects of light, temperature and pre-treatment (cold stratification) on the germination success of V. dioica seeds and the role of litter produced by different competitors on the early establishment of seedlings. We tested seeds from five populations differing in the level of competition for light and considered also the morphological variability of propagules and maternal plants. We found that V. dioica is able to germinate without light. It showed high germination percentages both under high summer temperatures independent of cold stratification and at low temperatures, but only after the stratification. Litter produced by dicotyledonous forbs was less hampering for the seedlings than that of small sedges or grasses. Valeriana dioica possesses a broad regeneration niche and is able to use gaps for germination and establishment both in spring and in summer. It reproduces successfully in herb-dominated fen meadow vegetation but disappears from reed communities. This study demonstrates the significant plasticity of the regeneration niche for a species with an intermediate life strategy and also stresses the importance of gaps for its reproduction.

中文翻译：

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从属草甸植物 Valeriana dioica L 的发芽要求

中生战略类型的植物物种是物种丰富的草原的特征，对干扰水平的变化很敏感。预计幼苗的萌发和早期建立是最关键的阶段，限制了适当地点的成功定植。Valeriana dioica 是一种典型的钙质植物，它依赖于通过适度的土地利用定期压制强大的竞争者。它在中欧的许多地方都濒临灭绝，包括下奥地利。我们研究了光、温度和预处理（冷分层）对 V. dioica 种子发芽成功的影响以及不同竞争者产生的枯枝落叶对幼苗早期建立的作用。我们测试了来自五个在光竞争水平上不同的种群的种子，并考虑了繁殖体和母体植物的形态变异性。我们发现 V. dioica 能够在没有光的情况下发芽。它在与冷分层无关的夏季高温下和低温下均显示出高发芽率，但仅在分层后。双子叶杂草产生的枯枝落叶对幼苗的影响小于小莎草或禾本科植物的枯枝落叶。Valeriana dioica 拥有广泛的再生生态位，能够利用间隙在春季和夏季发芽和建立。它在以草本植物为主的沼泽草甸植被中成功繁殖，但从芦苇群落中消失。