Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona, Spain.
Planta. 2012 Feb;235(2):349-58. doi: 10.1007/s00425-011-1513-x. Epub 2011 Sep 10.
It is still an unsolved question of fundamental biology if, and how, perennial plants senesce. Here, age- and sex-related changes in phytohormones were tested in Borderea pyrenaica, a small dioecious geophyte relict of the Tertiary with one of the longest lifespan ever recorded for any non-clonal herb (more than 300 years). Biomass allocation, together with levels of cytokinins, auxins and absicisic acid, and other indicators of leaf physiology (chlorophylls, lipid peroxidation and F (v)/F (m) ratio) were measured in juvenile and mature plants, including both males and females of three age classes (up to 50 years, 50-100 years, and over 100 years). Plants maintained intact capacity of their vegetative growth and reproductive potential. Cytokinin levels decreased with age, but only in females. Such sex-related differences, however, were not associated with symptoms of physiological deterioration in leaves, but with an increased reproductive effort in females. It is concluded that B. pyrenaica does not show clear signs of senescence at the organism level. Altered cytokinin levels in females were associated with their reproductive effort, rather than to a degenerative process. The alternate use of five meristematic points in the tuber could explain the extraordinary longevity of this species.
多年生植物是否以及如何衰老，这仍然是一个基础生物学尚未解决的问题。在这里，我们测试了博尔德雷亚·皮雷纳卡（Borderea pyrenaica）中的植物激素的年龄和性别相关变化，这是一种小型雌雄异株的古生代植物，是第三纪遗留下来的，其寿命是所有非克隆草本植物中记录最长的（超过 300 年）。在幼年期和成年期植物（包括三个年龄组的雄性和雌性：50 岁以下、50-100 岁和 100 岁以上）中，我们测量了生物量分配、细胞分裂素、生长素和脱落酸的水平以及其他叶片生理指标（叶绿素、脂质过氧化和 F(v)/F(m)比值）。植物保持了其营养生长和生殖潜力的完整能力。细胞分裂素水平随年龄增长而降低，但仅在雌性植物中如此。然而，这种性别相关的差异与叶片生理恶化的症状无关，而是与雌性生殖努力的增加有关。因此，博尔德雷亚·皮雷纳卡（B. pyrenaica）在机体水平上没有表现出明显的衰老迹象。雌性中细胞分裂素水平的改变与它们的生殖努力有关，而不是与退化过程有关。在块茎中使用五个分生点的交替可以解释该物种的非凡长寿。
