The effect of drought stress on inbreeding depression in four populations of the Mediterranean outcrossing plant Crepis sancta (Asteraceae)
The effect of drought stress on inbreeding depression in four populations of the Mediterranean outcrossing plant Crepis sancta (Asteraceae)
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DOI：
10.1046/j.1365-2540.2000.00759.x
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发表时间：
2000-09-01
期刊：
影响因子：
3.8
通讯作者：
Escarre, J
中科院分区：
文献类型：
--
作者：
Cheptou, PO;Berger, A;Escarre, J
生理胁迫对植物近交抑制程度的影响一直是少数研究的主题，并且由于结果相互矛盾，目前还存在争议。我们测量了三个干旱胁迫水平下的近交衰退，这是通过初步生理实验精确定义的。我们还测试了这样的假设：由于有害突变的清除，自交亲和性更高的种群表现出近亲繁殖抑制的减少。这项研究是针对从法国地中海地区收集的一年生异花植物 Crepis saintta 的两个种群以及来自具有不同自交不亲和水平的边缘地区的另外两个种群进行的。干旱胁迫并没有增加植物死亡率方面的近交抑制，但显着增加了首次开花日期、每株植物的头数和相对生长率的近交抑制。最自体受精的边缘种群在大多数测量的性状中都表现出不存在近交衰退，这表明该种群中可能发生了清除。其他三个种群对近交衰退的估计相对较低且相似（δ 约为 0.35）。与同种异体植物中发现的结果相比，获得的值相对较低，这表明我们的实验中没有对 C. saintta 进行竞争，可能低估了发生竞争的自然种群中近亲繁殖的影响。
The effect of physiological stress on the magnitude of inbreeding depression in plants has been the subject of few studies and is currently controversial because of contradictory results. We measured the inbreeding depression at three drought stress levels, precisely defined by a preliminary physiological experiment. We also tested the hypothesis that more highly self-compatible populations exhibit reduced inbreeding depression due to purging of deleterious mutations. The study was conducted on two populations of the annual and allogamous plant Crepis sancta collected from the French Mediterranean region and two other populations from marginal areas with various self-incompatibility levels. Drought stress did not increase inbreeding depression in terms of plant mortality but significantly increased the inbreeding depression for the date of first flowering, number of heads per plant and relative growth rate. The most self-fertile marginal population showed an absence of inbreeding depression in most of the measured traits indicating that purging could have taken place in this population. The three others populations showed relatively low and similar estimates of inbreeding depression (delta approximate to 0.35). The relatively low values obtained compared to the results found in allogamous plants suggests that the absence of competition for C. sancta in our experiment probably underestimated the effects of inbreeding in natural populations where competition occurs.