Phenological associations of within- and among-plant variation in gender with floral morphology and integration in protandrous Delphinium glaucum
Phenological associations of within- and among-plant variation in gender with floral morphology and integration in protandrous Delphinium glaucum
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早熟飞燕草植物内和植物间性别变异与花形态和整合的物候关联
DOI：
10.1111/j.1365-2745.2012.01976.x
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发表时间：
2012
影响因子：
5.5
通讯作者：
Harder LD
中科院分区：
文献类型：
--
作者：
Ishii HS;Harder LD
1.在种群的开花季节，雌雄同体的植物内部和之间的开花时间差异使花的性别比例从雄性向雌性转变。这种动态应诱导负频率依赖性选择，有利于早期开花和早期开花的植物比晚期开花和晚期开花的个体在雌性功能上投入相对更多的资源和时间。相反，选择花的整合，以促进花粉输出和输入应限制花的变异。2.我们评估了这些对比的预期为protandrousDelphinium glaucum考虑的变异和共变异的关系，花被片的长度，花药和胚珠的数量，和雌雄阶段的持续时间在花序内的三个位置的第一个开花日期，34株植物的平均性别和大小。3.生殖表型在植物之间和植物内的变化与群体花性别比从雄性到雌性的偏移有关，但与植物大小无关。早花植物具有雌性偏向的表型性别和较小的花，每个胚珠的花药较少，雄性阶段比晚花植物短。在个人，早期（下）花较大，更高的女性努力，无论是在相对生产的胚珠和花药和相对持续时间的女性和男性阶段，比后来（上）花。总体而言，这些结果更符合负频率依赖选择的预期，而不是近似资源分配。4.花部性状之间的相关性表明了显著的花部整合。然而，这些相关性从下部到上部花减弱，表明个体内变异的模式限制了整合的程度。5.合成。生殖表型包括系统的花间变异，并且随着开花时间在个体之间一致地变化，如D. glaucum所表现的，可能是具有多花花序的雌雄异熟物种的典型。植物内部和植物之间的这种多样性应该是由密度依赖性选择和频率依赖性选择的结合造成的，密度依赖性选择反对同时开花的个体，频率依赖性选择倾向于强调开花季节特定阶段中最不常见的性别角色，两者都受到伴随个体之间异步开花的积极的选择性交配的促进。
1.Flowering‐time differences within and among protandrous, hermaphroditic plants shift the floral sex ratio from male‐ to female‐dominated during a population’s flowering season. This dynamic should induce negative frequency‐dependent selection favouring relatively greater investment of resources and time in female function by early flowers and early‐flowering plants than by late flowers and late‐flowering individuals. In contrast, selection for floral integration to facilitate pollen export and import should limit floral variation.2.We assessed these contrasting expectations for the protandrousDelphinium glaucumby considering the relation of variation and covariation in the lengths of perianth segments, anther and ovule number, and male‐ and female‐phase duration for flowers at three positions within inflorescences to the first flowering date, mean gender and size of 34 plants.3.Reproductive phenotypes varied among and within plants in association with a shift in population floral sex ratio from male‐ to female‐biased, but not with plant size. Early‐flowering plants had female‐biased phenotypic gender and smaller flowers with fewer anthers per ovule and shorter male phases than late‐flowering plants. Within individuals, earlier (lower) flowers were larger with higher female effort, in terms of both the relative production of ovules and anthers and the relative durations of female and male phases, than later (upper) flowers. Overall, these results are more consistent with the expectations of negative frequency‐dependent selection than with proximate resource allocation.4.Correlations among floral traits indicated significant floral integration. However, these correlations weakened from lower to upper flowers, suggesting that the patterns of intra‐individual variation limit the extent of integration.5.Synthesis. Reproductive phenotypes that incorporate systematic among‐flower variation and vary consistently among individuals with flowering time, such as those exhibited byD. glaucum, may be typical of dichogamous species with multi‐flowered inflorescences. Such diversity within and among plants should result from a combination of density‐dependent selection against simultaneous flowering of individuals and frequency‐dependent selection favouring emphasis on the least common sex role during specific stages of the flowering season, both facilitated by the positive assortative mating that accompanies asynchronous flowering among individuals.