Qiu Taijia, Li Song, Zhao Kunkun, Jia Diwen, Chen Fadi, Ding Lian
National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China.
Key Laboratory of Flower Biology and Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China.
Plants (Basel). 2023 Oct 30;12(21):3728. doi: 10.3390/plants12213728.
The chrysanthemum is widely used as a cut flower, potted flower, and garden flower worldwide and has high ornamental, edible, and medicinal value. The flower heads, composed of ray florets and disc florets, are the most diverse in terms of morphology among ornamental plants. Here, we compared and analyzed the developmental processes of different capitulum types as well as ray florets and disc florets. Morphological differentiation of the two florets occurred on the dorsal domain of the petals at stage Ⅳ of flower development, and differences in stamen development occurred at stage Ⅴ. The dorsal domain of the ray florets and the early stage of flower development were also an essential site and period, respectively, for the differences among capitulum types. In situ hybridization revealed that , whose homologs are involved in the specification of floret identity in Asteraceae, was expressed in both the dorsal and ventral domains of the ray petals in the tubular-type chrysanthemum, whereas, it was differentially transcribed in the ray petals of flat- and spoon-type chrysanthemum cultivars and had lower or no expression in the dorsal domain and higher expression in the ventral domain at stage Ⅳ. Our study indicates that the expression pattern of on the dorsal domain of the ray floret at stage Ⅳ contributes to the formation of diverse flower head types in chrysanthemums.
菊花在全球范围内被广泛用作切花、盆栽花卉和园林花卉，具有很高的观赏、食用和药用价值。由舌状花和管状花组成的花头，在观赏植物中形态最为多样。在此，我们对不同头状花序类型以及舌状花和管状花的发育过程进行了比较和分析。两种小花的形态分化发生在花发育的Ⅳ期花瓣的背侧区域，雄蕊发育的差异发生在Ⅴ期。舌状花的背侧区域和花发育的早期阶段，分别也是头状花序类型差异的关键部位和时期。原位杂交显示，其同源物参与菊科小花身份的确定，在管状型菊花舌状花瓣的背侧和腹侧区域均有表达，而在平瓣型和匙瓣型菊花品种的舌状花瓣中差异转录，在Ⅳ期背侧区域表达较低或无表达，在腹侧区域表达较高。我们的研究表明，Ⅳ期舌状花背侧区域的表达模式有助于菊花多种花头类型的形成。
