Experimental dissection of inbreeding and its adaptive significance in a flowering plant, Aquilegia canadensis (Ranunculaceae)
Experimental dissection of inbreeding and its adaptive significance in a flowering plant, Aquilegia canadensis (Ranunculaceae)
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DOI：
10.1111/j.0014-3820.2004.tb01622.x
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发表时间：
2004-12-01
期刊：
影响因子：
3.3
通讯作者：
Eckert, CG
中科院分区：
文献类型：
--
作者：
Herlihy, CR;Eckert, CG
近亲繁殖是许多动植物种群交配系统的主要组成部分，特别是两性物种。在开花植物中，近亲繁殖可以通过花内自花授粉（自花受精）、同一植物上的花之间自花授粉（geitonogamy）或密切相关的个体之间的异花授粉（双亲近亲繁殖）发生。我们进行了花去雄实验，在10个群体的Aquilegia canadensis（毛茛科），并使用等位酶标记估计的相对贡献，每一种模式的近亲交配系统。我们还研究了这些近交模式如何受到种群结构和花形态方面的影响，并且预计展示会影响交配系统。所有的种群都进行了大量的近亲繁殖。平均而言，只有25%的种子是通过异交产生的（种群间的范围= 9-37%），这与种群大小（r = +0.61）和密度（r = +0.64）呈正相关。近亲繁殖发生通过自花授粉和双亲近亲繁殖，和每一个的相对贡献是高度可变的种群之间。估计geitonogamy没有显着大于零的任何人口。我们检测到大量的双亲近交（平均值= 14%的种子，范围= 4-24%），估计明显的出售在去雄植物没有机会真正的自交。这种模式的近亲繁殖与人口规模呈负相关（r = -0.87）和冠层覆盖呈正相关（r = +0.90），这表明人口的特点，增加异交花粉转移减少双亲近亲繁殖。自花受精是所有种群中交配系统的最大组成部分（平均值= 58%，范围= 37-84%），并且正如预期的那样，在具有最多雌雄花受精花的种群中最低（r = -0.59）。虽然自花受精在自然种群中提供了繁殖保证。canadensis，它折扣胚珠使上级异交种子。因此，在这些人群中的高自体受精似乎是不利的，因此很难解释广泛的变化，在herkogamy观察之间，特别是在人群内。
Inbreeding is a major component of the mating system in populations of many plants and animals, particularly hermaphroditic species. In flowering plants, inbreeding can occur through self-pollination within flowers (autogamy), self-pollination between flowers on the same plant (geitonogamy), or cross-pollination between closely related individuals (biparental inbreeding). We performed a floral emasculation experiment in 10 populations of Aquilegia canadensis (Ranunculaceae) and used allozyme markers to estimate the relative contribution of each mode of inbreeding to the mating system. We also examined how these modes of inbreeding were influenced by aspects of population structure and floral morphology and display predicted to affect the mating system. All populations engaged in substantial inbreeding. On average, only 25% of seed was produced by outcrossing (range among populations = 9-37%), which correlated positively with both population size (r = +0.61) and density (r = +0.64). Inbreeding occurred through autogamy and biparental inbreeding, and the relative contribution of each was highly variable among populations. Estimates of geitonogamy were not significantly greater than zero in any population. We detected substantial biparental inbreeding (mean = 14% of seeds, range = 4-24%) by estimating apparent selling in emasculated plants with no opportunity for true selfing. This mode of inbreeding correlated negatively with population size (r = -0.87) and positively with canopy cover (r = +0.90), suggesting that population characteristics that increase outcross pollen transfer reduce biparental inbreeding. Autogamy was the largest component of the mating system in all populations (mean = 58%, range = 37-84%) and, as expected, was lowest in populations with the most herkogamous flowers (r = -0.59). Although autogamy provides reproductive assurance in natural populations of A. canadensis, it discounts ovules from making superior outcrossed seed. Hence, high autogamy in these populations seems disadvantageous, and therefore it is difficult to explain the extensive variation in herkogamy observed both among and especially within populations.