报春花二型花柱综合征的破坏。
Disruption of the distylous syndrome in Primula veris.
作者信息
Brys Rein, Jacquemyn Hans
机构信息
Division of Plant Ecology and Systematics, Biology Department, University of Leuven, Belgium and Research Institute for Nature and Forest, Kliniekstraat 25, BE-1070 Brussels, Belgium Division of Plant Ecology and Systematics, Biology Department, University of Leuven, Belgium and Research Institute for Nature and Forest, Kliniekstraat 25, BE-1070 Brussels, Belgium
Division of Plant Ecology and Systematics, Biology Department, University of Leuven, Belgium and Research Institute for Nature and Forest, Kliniekstraat 25, BE-1070 Brussels, Belgium.
出版信息
Ann Bot. 2015 Jan;115(1):27-39. doi: 10.1093/aob/mcu211. Epub 2014 Nov 26.
BACKGROUND AND AIMS
Distyly is a floral polymorphism characterized by the presence of two discrete morphs with reciprocal positioning of anthers and stigmas in flowers on different plants within the same population. Although reciprocal herkogamy and associated floral traits are generally thought to be discrete and strict polymorphisms, little is known about variation in floral traits related to the distylous syndrome within and among populations of a single species. In this study, variation in floral morphology and reciprocal positioning of the sexual organs in the distylous Primula veris (cowslip) is quantified.
METHODS
Data were collected in ten populations occurring in two contrasting habitat types (grasslands and forests), and for each population the average level of reciprocity was assessed, the strength of the self-incompatibility system was determined, and seed production under natural conditions was quantified.
RESULTS
In grassland populations, flowers showed clear distyly with low and symmetric reciprocity indices at both the lower and upper level. In forests, P. veris produced larger flowers that showed strong deviations in stigma-anther separation, especially in the L-morph. This deviation was mainly driven by variation in stigma height, resulting in high and asymmetric reciprocity indices and the occurrence of several short-styled homostylous plants. Self-incompatibility was, however, strict in both habitats, and morph ratios did not differ significantly from isoplethy. The observed shift in reciprocity in forest populations was associated with a significant reduction in seed production in the L-morph.
CONCLUSIONS
The results indicate that populations of P. veris show habitat-specific variation in flower morphology. Deviations from perfect reciprocal positioning of stigmas and anthers also translate into reduced seed production, suggesting that small changes in sexual organ reciprocity can have far-reaching ecological and evolutionary implications.
背景与目的
花柱异长是一种花的多态现象，其特征是在同一群体内不同植株的花中存在两种不同形态，花药和柱头相互异位。尽管互异型雌雄异位及相关花部性状通常被认为是离散且严格的多态现象，但对于单一物种的种群内和种群间与花柱异长综合征相关的花部性状变异却知之甚少。在本研究中，对花柱异长的报春花（黄花九轮草）的花部形态变异和性器官的相互定位进行了量化。
方法
在两种不同的栖息地类型（草地和森林）中的10个种群中收集数据，对每个种群评估互作的平均水平，确定自交不亲和系统的强度，并对自然条件下的种子产量进行量化。
结果
在草地种群中，花表现出明显的花柱异长，上下层的互作指数均较低且对称。在森林中，报春花产生的花更大，柱头与花药的分离表现出强烈偏差，尤其是在长花柱形态中。这种偏差主要由柱头高度的变异驱动，导致互作指数高且不对称，以及出现了几株短花柱的同型花柱植物。然而，在这两种栖息地中自交不亲和都很严格，形态比例与理论比例没有显著差异。在森林种群中观察到的互作变化与长花柱形态的种子产量显著降低有关。
结论
结果表明，报春花种群在花部形态上表现出特定于栖息地的变异。柱头和花药完美相互定位的偏差也会导致种子产量降低，这表明性器官互作的微小变化可能具有深远的生态和进化意义。
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