Barabé Denis, Lacroix Christian, Jeune Bernard
Institut de recherche en biologie végétale, Jardin botanique de Montréal, Université de Montréal, 4101 Sherbrooke Est, Montréal, H1X 2B2, Canada.
Ann Bot. 2008 May;101(7):1027-34. doi: 10.1093/aob/mcn031. Epub 2008 Mar 20.
The inflorescence of Philodendron constitutes an interesting morphological model to analyse the phenomenon of homeosis quantitatively at the floral level. The specific goals of this study were (1) to characterize and quantify the range of homeotic transformation in Philodendron billietiae, and (2) to test the hypothesis that the nature of flowers surrounding atypical bisexual flowers (ABFs) channel the morphological potentialities of atypical bisexual flowers.
Inflorescences of P. billietiae at different stages of development were observed using SEM. The number of appendices in male, female and sterile flowers were counted on 11 young inflorescences (5-6 flowers per inflorescence). The number of staminodes and carpels on ABFs were counted on 19 inflorescences (n = 143). These data were used for regression and ANOVA analyses.
There was an average of 4.1 stamens per male flower, 9.8 carpels per female flower and 6.8 staminodes per sterile male flower. There was an average of 7.3 floral appendices per atypical flower. Staminodes and carpels are inserted on the same whorl in ABFs. A negative exponential relationship was found between the average number of staminodes and the number of carpels in ABFs. If only the ABFs consisting of less than six carpels are considered, there is a linear relationship between the number of carpels and the average number of staminodes. The value of the slope of the regression equation indicates that on average, in P. billietiae, 1.36 carpels are replaced by one staminode.
In P. billietiae, the number of appendages in female flowers imposes a constraint on the maximum total number of appendages (carpels and staminodes) that can develop on ABFs. The quantitative analyses indicate that the average number of different types of floral appendages on an ABF and the number of organs involved in a homeotic transformation are two independent phenomena.
喜林芋属植物的花序构成了一个有趣的形态学模型，可用于在花的层面定量分析同源异型现象。本研究的具体目标是：（1）描述和量化比氏喜林芋同源异型转变的范围；（2）检验如下假设：围绕非典型两性花（ABF）的花的性质决定了非典型两性花的形态潜能。
使用扫描电子显微镜观察处于不同发育阶段的比氏喜林芋的花序。在11个幼嫩花序（每个花序有5 - 6朵花）上统计雄花、雌花和不育花中的附属物数量。在19个花序（n = 143）上统计非典型两性花中的退化雄蕊和心皮数量。这些数据用于回归分析和方差分析。
雄花平均有4.1枚雄蕊，雌花平均有9.8枚心皮，不育雄花平均有6.8枚退化雄蕊。非典型花平均有7.3个花附属物。在非典型两性花中，退化雄蕊和心皮着生于同一轮。在非典型两性花中，退化雄蕊的平均数量与心皮数量之间呈负指数关系。如果仅考虑心皮数少于6个的非典型两性花，则心皮数量与退化雄蕊平均数量之间存在线性关系。回归方程斜率值表明，在比氏喜林芋中，平均1.36个心皮被1个退化雄蕊取代。
在比氏喜林芋中，雌花中的附属物数量限制了非典型两性花上可发育的附属物（心皮和退化雄蕊）的最大总数。定量分析表明，非典型两性花上不同类型花附属物的平均数量与同源异型转变中涉及的器官数量是两个独立的现象。
