Members of the genus Paphiopedilum are world-famous for their large, colourful flowers, unique floral morphology and long floral lifespan. Most Paphiopedilum species bloom in spring or autumn. The control of flowering time is of great significance to the commercial production of floral crops, because it affects the sales and prices of flowers. However, the mechanism that regulates when Paphiopedilum species bloom is unclear. In the present study, floral bud initiation and development of P. micranthum (spring-flowering species with one flower per stalk), P. dianthum (autumn-flowering species with multiple flowers per stalk) and P. henryanum (autumn-flowering species with one flower per stalk) were investigated by morphological and anatomical methods. We divided Paphiopedilum floral bud differentiation into six phases: the initiation of differentiation, inflorescence primordium differentiation, flower primordium differentiation, sepal primordium differentiation, petal primordium differentiation and column primordium differentiation. We found that the timing of floral bud differentiation for the three species was synchronized when experiencing the same environment, while the period from initiation to flowering largely differed. In addition, initiation of floral bud differentiation in P. dianthum was earlier at a warmer environment. The difference in flowering time of three species was mainly caused by the duration of floral bud development, rather than the initiation time. The findings were of great significance for the cultivation and flowering regulation of Paphiopedilum species.

中文翻译：

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兜兰品种的季节性开花时间是否是由花芽分化起始时间的差异引起的？


兜兰属植物以其硕大、色彩缤纷的花朵、独特的花形和较长的花期而闻名于世。大多数兜兰品种在春季或秋季开花。开花时间的控制对于花卉作物的商业化生产具有重要意义，因为它影响花卉的销售和价格。然而，调节兜兰物种开花时间的机制尚不清楚。在本研究中，P. micranthum（春花品种，每茎一朵花）、P. dianthum（秋花品种，每茎多花）和 P. henryanum（秋花品种，每茎多朵花）的花芽萌发和发育。每茎一朵花）通过形态学和解剖学方法进行了研究。将兜兰花芽分化分为6个阶段：分化起始期、花序原基分化期、花原基分化期、萼片原基分化期、花瓣原基分化期和柱原基分化期。我们发现，在经历相同环境时，这三个物种的花芽分化时间是同步的，但从萌芽到开花的时间却有很大差异。此外，在较温暖的环境下，石竹花芽分化的起始时间较早。三个物种开花时间的差异主要是由花芽发育的持续时间引起的，而不是由花芽萌生时间引起的。该研究结果对于兜兰属植物的栽培和开花调控具有重要意义。