Martínková Jana, Šmilauer Petr, Mihulka Stanislav, Latzel Vít, Klimešová Jitka
Institute of Botany, The Czech Academy of Sciences, Dukelská 135, 379 82 Třeboň, Czech Republic,
University of South Bohemia, Faculty of Science, Branišovská 1760, 370 05 České Budějovice, Czech Republic and.
Ann Bot. 2016 Apr;117(4):667-79. doi: 10.1093/aob/mcw010. Epub 2016 Mar 14.
Senescence is the process of losing fitness when growing old, and is shaped by the trade-off between maintenance and reproduction that makes reproduction more unsure and maintenance more costly with age. In repeatedly reproducing plants, reductions in growth and fertility are signs of senescence. Disturbance, however, provides an opportunity to reset the ageing clock and consequently potentially ameliorate senescence.
To test the effects of disturbance on traits closely related to fitness and thus to senescence, a long-term garden experiment was established with two short-lived perennial congeners,Barbarea vulgaris and Barbarea stricta, that differ in their ability to resprout after injury. In the experiment, five damage treatments were applied to plants in four different phenophases.
It was found that damage to the plant body significantly prolonged life span in B. vulgaris but decreased whole-life seed production in both species. High concentration of seed production in one growing season characterized short life spans. Both more severe damage and a more advanced phenological phase at the time of damage caused reproduction to be spread over more than one growing season and equalized per-season seed production. In terms of seed quality, average weight of a single seed decreased and seed germination rate increased with age regardless of damage.
Although disturbance is able to reset the ageing clock of plants, it is so harmful to plant fitness that resprouting serves, at best, only to alleviate slightly the signs of senescence. Thus, in terms of whole-life seed production, injured plants were not more successful than uninjured ones in the two studied species. Indeed, in these species, injury only slightly postponed or decelerated senescence and did not cause effective rejuvenation.
衰老指生物体在变老过程中机能衰退的过程，它由维持与繁殖之间的权衡所塑造，随着年龄增长，繁殖变得更不稳定，维持成本更高。在多次繁殖的植物中，生长和繁殖力的下降是衰老的标志。然而，干扰为重置衰老时钟提供了机会，从而有可能改善衰老状况。
为了测试干扰对与适合度密切相关从而与衰老相关的性状的影响，利用两种一年生多年生同属植物——普通山芥和窄叶山芥，建立了一个长期的花园实验，这两种植物在受伤后再发芽的能力有所不同。在实验中，对处于四个不同物候期的植物施加了五种损伤处理。
发现对植物体的损伤显著延长了普通山芥的寿命，但降低了两个物种的全生命周期种子产量。一个生长季节内种子产量高的特点是寿命短。更严重的损伤以及损伤时更晚的物候期都会导致繁殖分布在多个生长季节，并使每个季节的种子产量趋于均衡。就种子质量而言，无论是否受到损伤，单粒种子的平均重量都会随着年龄增长而下降，种子发芽率则会上升。
尽管干扰能够重置植物的衰老时钟，但它对植物适合度的危害极大，以至于再发芽充其量只能略微减轻衰老的迹象。因此，就全生命周期种子产量而言，在这两个研究物种中，受伤的植物并不比未受伤的植物更成功。实际上，在这些物种中，损伤只是略微推迟或减缓了衰老，并没有导致有效的复壮。
