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

Abstract

Floral organ development and sex differentiation are key processes controlling plant reproduction and yield in angiosperms. The ABCDE model explains floral organ identity through the combinatorial action of MADS-box transcription factors; however, additional regulators such as SPL, WOX, NAC, TGA, and AGL6 further refine organ specification and meristem activity. Flowering is regulated by environmental signals, including photoperiod, temperature, and vernalization, as well as endogenous pathways involving hormones, sugars, and age-related microRNAs. Central regulatory modules, such as CO–FT, FLC, and miR156–miR172, integrate these signals to control the transition to flowering. Hormonal crosstalk and metabolic cues, particularly carbon–nitrogen balance, further modulate gene expression and developmental outcomes. Sex differentiation adds another layer of complexity to floral development. Although hermaphroditism is predominant among angiosperms, monoecious and dioecious species produce unisexual flowers through diverse genetic, developmental, hormonal, and environmental mechanisms, with sex-linked loci and differentiated sex chromosomes contributing in some lineages. These mechanisms contribute to reproductive diversity and adaptation in angiosperms. This review summarizes recent advances in the molecular and environmental regulation of floral development, flowering, and sex differentiation, highlighting gene regulatory networks, transcriptional control, and environmental signals, with implications for future research and crop improvement.