Several plant species display a temporal separation of the male and female flower organ development to enhance outbreeding; however, little is known regarding the genetic mechanisms controlling this temporal separation. Quercus suber is a monoecious oak tree with accentuated protandry: in late winter, unisexual male flowers emerge adjacent to the swollen buds, whereas unisexual female flowers emerge in the axils of newly formed leaves formed during spring (4–8 weeks after male flowering). Here, a phylogenetic profiling has led to the identification of cork oak homologs of key floral regulatory genes. The role of these cork oak homologs during flower development was identified with functional studies in Arabidopsis thaliana. The expression profile throughout the year of flower regulators (inducers and repressors), in leaves and buds, suggests that the development of male and female flowers may be preceded by separated induction events. Female flowers are most likely induced during the vegetative flush occurring in spring, whereas male flowers may be induced in early summer. Male flowers stay enclosed within the pre-dormant buds, but complete their development before the vegetative flush of the following year, displaying a long period of anthesis that spans the dormant period. Our results portray a genetic mechanism that may explain similar reproductive habits in other monoecious tree species.

中文翻译：

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雌雄性栎（Quercus suber L.）中的单性花萌生：一种分子方法。

几种植物表现出雌雄花器官发育的暂时性分隔，以增强近交。然而，关于控制这种暂时分离的遗传机制知之甚少。栎（Quercus suber）是一棵雌雄同体的橡树，带有浓重的藤本植物：在冬末，单性的雄花在肿胀的芽旁出现，而单性的雌花则在春季（雄性开花后4-8周）形成的新形成的叶腋中出现。在这里，系统发育分析导致对关键花卉调控基因的软木栎同系物的鉴定。通过对拟南芥的功能研究确定了这些软木栎同系物在花发育过程中的作用。。叶片和芽中的花调节剂（诱导剂和阻遏物）全年的表达情况表明，雄花和雌花的发育可能先于分开的诱导事件。雌花最有可能在春季发生的植物性潮红中被诱导，而雄花则可能在初夏被诱导。雄花保持在休眠前的花蕾中，但是在第二年的营养旺盛之前就完成了发育，表现出跨越休眠期的较长的花期。我们的研究结果描述了一种遗传机制，可以解释其他雌雄异株树种的类似繁殖习性。