Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona 08028, Spain.
Research Institute in Biodiversity (IRBio), University of Barcelona, Barcelona 08028, Spain.
Plant Physiol. 2023 Feb 12;191(2):974-985. doi: 10.1093/plphys/kiac540.
Ancient trees are life history longevity winners that mostly persist in remote and environmentally harsh mountainous areas. Here, we performed a multifeature analysis in a protected mature mountain pine (Pinus uncinata) forest to identify the morphological and physiological traits that make these trees unique. We compared the physiology of meristematic and somatic tissues (apical buds and needles, respectively) from juvenile, mature young, mature old, and mature ancient trees under cold stress and nonstress conditions. We successfully identified key morphological features of extreme longevity at the organism level, as well as various growth, vigor, stress, and dormancy markers underlying extreme longevity in old and ancient trees. Results indicated that evolution has exerted selective pressure on specific physiological traits that make trees become longevity winners (<0.1% of the tree population were ancient trees, with an average trunk diameter >100 cm and an estimated age of 700 years). Traits entailing longevity not only included apical dominance loss, epicormic growth, and modular senescence, but also an extreme plasticity in both meristematic and somatic tissues (buds and needles, respectively), as shown by various physiological markers. In conclusion, ancient trees are oddities that not only possess a unique ecological value but also show divergent physiological behaviors selected during their evolution to allow them to cope with adversities and attain long life.
古树是生命历史长寿的优胜者，它们大多存在于偏远且环境恶劣的山区。在这里，我们对一个受保护的成熟高山松林（Pinus uncinata）进行了多特征分析，以确定使这些树木具有独特性的形态和生理特征。我们比较了在冷胁迫和非胁迫条件下，幼树、成熟小树、成熟老树和成熟古树的分生组织和体细胞（分别为顶芽和针叶）的生理学特性。我们成功地鉴定了在生物体水平上的极端长寿的关键形态特征，以及老树和古树中存在的各种生长、活力、胁迫和休眠标志。结果表明，进化对使树木成为长寿优胜者的特定生理特征施加了选择性压力（<0.1%的树木为古树，平均树干直径>100 厘米，估计年龄为 700 年）。长寿特征不仅包括顶端优势丧失、副梢生长和模块化衰老，还包括分生组织和体细胞（分别为芽和针叶）的极端可塑性，这可以通过各种生理标记来证明。总之，古树是奇异的存在，它们不仅具有独特的生态价值，而且表现出在进化过程中选择的不同生理行为，使它们能够应对逆境并获得长寿。
