Senescence in duckweed: age-related declines in survival, reproduction and offspring quality
Senescence in duckweed: age-related declines in survival, reproduction and offspring quality
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DOI：
10.1111/1365-2435.12359
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发表时间：
2015-04-01
影响因子：
5.2
通讯作者：
Laird, Robert A.
中科院分区：
文献类型：
--
作者：
Barks, Patrick M.;Laird, Robert A.
随着年龄的增长，大多数生物体都会经历渐进的生理退化，导致生存和繁殖率下降-一种被称为衰老的看似适应不良的现象。虽然衰老通常只与生存和繁殖有关，但健康的第三个组成部分，即后代质量，也可能随着年龄的增长而下降。然而，很少有研究使用真正反映健康的措施来评估与年龄相关的后代质量变化。在一个受控的环境中，我们测试了年龄相关的下降在三个人口组成部分的健身（生存，繁殖和后代质量）在浮萍，一个小的水生植物在亚科浮萍（浮萍）的寿命短，无性繁殖的速度快。我们对后代质量的主要衡量标准，即内在增长率，比以前的研究中使用的尺寸，寿命和总生殖输出等措施更接近健康。我们观察到与年龄相关的健康的所有三个组成部分的下降：老植物的存活率和繁殖率较低，产生的后代质量低于年轻植物。衰老进化生物学的理论和实证研究应更多地关注后代质量。这种经常被忽视的适应性成分可能会随着年龄的增长而变化--正如我们在小乳杆菌中所展示的那样--而且可能会受到导致衰老的相同进化力量的影响，并反馈给这些进化力量。
As they grow old, most organisms experience progressive physiological deterioration resulting in declining rates of survival and reproduction - a seemingly maladaptive phenomenon known as senescence. Although senescence is usually defined with respect only to survival and reproduction, a third component of fitness, offspring quality, may also decline with age. Few studies, however, have assessed age-related changes in offspring quality using measures that truly reflect fitness. In a controlled environment, we tested for age-related declines in three demographic components of fitness (survival, reproduction and offspring quality) in Lemna minor, a small aquatic plant in the subfamily Lemnoideae (the duckweeds) with a short life span and rapid rate of asexual reproduction. Our primary measure of offspring quality, the intrinsic rate of increase, more closely approximates fitness than measures used in previous studies such as size, life span and total reproductive output. We observed strong age-related declines in all three components of fitness: old plants had lower rates of survival and reproduction, and produced lower-quality offspring than younger plants. Theoretical and empirical research on the evolutionary biology of senescence should devote more attention to offspring quality. This often unrecognized component of fitness may change with age - as we have shown in L.minor - and may be shaped by, and feed back into, the same evolutionary forces that give rise to senescence.