PDF(Pubmed)
Abstract：
Quillworts (Isoëtes) represent highly specialized flora of softwater lakes, that is, freshwater ecosystems potentially sensitive to acidification. In this paper, we combine a review of previous studies and our new results to address unrecognized reproduction strategies of quillworts to overcome long-term environmental stresses. These strategies play an important role in the plant\'s ability to overcome atmospheric acidification of freshwaters, protecting the plants until their environment can recover. Environmental drivers of recovery of Isoëtes echinospora and I. lacustris were studied in two acidified lakes in the Bohemian Forest (Central Europe). Both populations survived more than 50 years of severe acidification, although they failed to recruit new sporelings. Their survival depended entirely on the resistance of long-living adult plants because the quillworts do not grow clonally. During the past two decades, a renewal of I. echinospora population inhabiting Plešné Lake has been observed, while no such renewal of I. lacustris, dwelling in Černé Lake, was evident, despite similar changes in water composition occurring in both lakes undergoing advanced recovery from acidification. Our in vitro experiments revealed that the threshold acidity and toxic aluminium concentrations for sporeling survival and recruitment success differed between I. echinospora (pH ≤ 4.0 and ≥300 μg L-1 Al at pH 5) and I. lacustris (pH ≤ 5.0 and ≥100 μg L-1Al at pH 5). The higher sensitivity of I. lacustris to both stressors likely stems from its year-long germination period and underlines the risk of exposure to chronic or episodic acidification in recovering lakes. By contrast, the shorter germination period of I. echinospora (2-3 months) enables its faster and deeper rooting, protecting this quillwort from periodic acidification during the next snowmelt. Our study brings novel insights into widely discussed environmental issues related to the long-term degradation of softwater lakes, which represent important hotspots of pan-European biodiversity and conservation efforts.
摘要：
Quillworts（Isotes）代表了软水湖泊的高度专业化的植物区系，也就是说,淡水生态系统可能对酸化敏感。在本文中,我们将对先前研究的回顾和我们的新结果相结合，以解决未被认可的仙草繁殖策略，以克服长期的环境压力。这些策略在植物克服淡水大气酸化的能力中起着重要作用，保护植物直到他们的环境可以恢复。在波西米亚森林（中欧）的两个酸化湖泊中研究了Isoesechinospora和I.lacustris恢复的环境驱动因素。这两个种群都在严重酸化中存活了50多年，尽管他们没有招募新的间谍。它们的生存完全取决于长期存活的成年植物的抗性，因为拟南芥不会无性系生长。在过去的二十年里，已观察到居住在PlenéLake的I.echinospora种群的更新，虽然没有这种I.lacustris的更新，居住在erné湖，很明显,尽管两个湖泊的水成分发生了类似的变化，但从酸化中进行了高级恢复。我们的体外实验表明，在I.echinospora（pH≤4.0且在pH5时≥300μgL-1Al）和I.lacustris（pH≤5.0且≥100μgL-1Al在pH5时）之间，阈值酸度和有毒铝浓度对于孢子存活和募集成功是不同的。I.lacustris对两种压力的敏感性较高，可能源于其长达一年的发芽期，并强调了在恢复的湖泊中暴露于慢性或周期性酸化的风险。相比之下,较短的发芽期（2-3个月）使其更快，更深的生根，在下一次融雪过程中保护这种酸草免受周期性酸化。我们的研究为广泛讨论的与软水湖泊长期退化有关的环境问题带来了新的见解，代表了泛欧生物多样性和保护工作的重要热点。
