Molecular and environmental regulation of floral development, flowering, and sex differentiation in angiosperms

Flowers, the reproductive organs of spermatophytes, are essential for fruit and seed formation and thus play a central role in plant reproductive success [ 1 ]. A typical angiosperm flower consists of four floral whorls: the calyx (sepals), corolla (petals), androecium (stamens), and gynoecium (carpels). Ovules are borne within the ovary of the gynoecium and develop into seeds following fertilization. Considerable variation in floral structure occurs among species [ 2 , 3 ]. For example, Eucommia ulmoides and Salix babylonica produce unisexual flowers containing either stamens or pistils. Viburnum opulus produces flowers lacking reproductive organs, whereas Morus species often lack petals [ 2 , 4 ]. These variations highlight the diversity of floral structure and the complexity of developmental regulation. Floral organ development is governed by intricate genetic networks and influenced by both endogenous physiological signals and environmental cues [ 5 ]. The discovery of MADS-box transcription factors, including MCM1, AGAMOUS (AG), DEFICIENS (DEF), and serum response factor (SRF), established a foundation for understanding the molecular regulation of flower development [ 6 , 7 ]. The classical ABCDE model provides a framework for understanding floral organ identity through the combinatorial action of floral homeotic genes [ 8 ]. However, floral organogenesis involves additional transcription factors and regulatory genes that extend beyond this classical framework [ 8 , 9 , 10 ]. These regulatory networks integrate floral meristem identity, organ specification, developmental timing, and reproductive development.