Department of Biology, University of Fribourg, Pèrolles, 1700 Fribourg, Switzerland.
Am J Bot. 2001 Sep;88(9):1593-9.
Adaptation of the annual plant Senecio vulgaris to ruderal and agricultural habitats was investigated. We expected S. vulgaris to be adapted to the agricultural habitat through nutrient-specific differentiation of relatively few genotypes responding to the generally high homogenous nutrient levels at the agricultural habitat caused by constant fertilization. To assess adaptation of S. vulgaris, vegetative and reproductive responses of seed families from various populations of agricultural and ruderal habitats, grown in the greenhouse at high and low nutrient levels, were compared. Data were analyzed with a three-level nested ANOVA based on the levels habitat, population, and family. A significant habitat effect indicated that S. vulgaris from ruderal and agricultural habitats were genetically different with plants from the agricultural habitat having larger leaves and a higher reproduction. A significant habitat by nutrient effect showed a stronger response of reproduction to nutrients at the agricultural habitat, suggesting that genetic differentiation among habitats is nutrient-specific. Contrary to expectations, only the agricultural habitat showed genetic diversity of S. vulgaris. Results suggest that nutrient levels at the agricultural habitat are more heterogeneous as generally proposed leading to a relatively high genetic variation.
我们研究了一年生植物千里光对杂草和农业生境的适应。我们期望千里光通过对相对较少的基因型的营养特异性分化来适应农业生境，这些基因型对农业生境中由于持续施肥而导致的普遍高均匀养分水平做出反应。为了评估千里光的适应性，我们比较了来自农业和杂草生境的不同种群的种子家族在温室中高和低养分水平下的营养和繁殖反应。数据使用基于栖息地、种群和家族三个层次的嵌套 ANOVA 进行分析。栖息地的显著影响表明，来自杂草和农业生境的千里光在遗传上是不同的，农业生境中的植物具有更大的叶子和更高的繁殖力。栖息地与养分的显著交互作用表明，对农业生境中的养分的繁殖反应更强，这表明生境之间的遗传分化是营养特异性的。与预期相反，只有农业生境显示出千里光的遗传多样性。结果表明，农业生境中的养分水平比普遍认为的更具异质性，从而导致相对较高的遗传变异。
