Floral Anatomy, Sporogenesis, and Gametogenesis in the Rubber Dandelion (Taraxacum kok-saghyz): Implications for Breeding and Crop Development.

Taraxacum kok-saghyz (TK), the rubber dandelion, is an emerging crop offering potential for sustainable natural rubber production independent of tropical climates. Successful domestication of TK requires a mechanistic understanding of its reproductive biology, yet floral anatomy, sporogenesis, and gametogenesis remain poorly characterized. We hypothesized that TK's reproductive development follows the general patterns of sexually reproducing diploid Taraxacum species and other Asteraceae, distinguishable from the irregular meiosis reported in apomictic taxa. Here, using light and scanning electron microscopy across multiple developmental stages, we describe the floral and inflorescence anatomy, as well as sporogenesis and gametogenesis in TK. Anther development in TK predominantly follows the simultaneous microsporogenesis pattern, typical of eudicots, producing regular tetrahedral tetrads. Notably, we also observed occasional successive-type events resulting in dyads and tetragonal tetrads, indicating a previously unreported developmental variation within the species, culminating in mature tricellular pollen. We detail key reproductive structures, including anther wall layers, ovary mesophyll differentiation, and the presence of a micropylar obturator. The meiotic behavior and gametophyte development observed in TK are consistent with those of diploid, sexually reproducing Taraxacum species and other members of the Asteraceae, in contrast to the irregular meiosis reported in Taraxacum apomictic taxa. These newly described morphoanatomical details on reproductive aspects will inform breeding strategies and advance our understanding of pollination, fertilization, and seed development in TK.