Chapter 5: The Y chromosome of white campion: sexual dimorphism and beyond.

The article focuses on the study of Y chromosome of white campion (Silene latifolia). The Y chromosome contains key genes controlling the sexual dimorphism. In male plants, a filamentous structure replaces the pistil, while in female plants the stamens degenerate early in flower development. In the absence of stamen promoting function located on the Y chromosome, the male developmental arrest in the female flower results from the lack of parietal initials and the subsequent degeneration of sporogenous cell initials during anther differentiation. Thus, the female plant (XX constitution) contains the genetic information necessary to initiate anther development up to the early sporogenous stage. Subsequently, anther development is arrested because the genes required to proceed beyond that stage are not expressed or are missing. flower. In the presence of gynoecium suppression function (GSF), located on the Y chromosome, the female developmental arrest in the male flower results from a block in carpel initiation. The male plant (XY constitution) contains all the genetic information to produce a functional hermaphroditic flower, while the GSF causes a sudden arrest of cell proliferation in whorl 4 of male flowers at the time of partitioning between whorls 3 and 4, at the flower meristem centre.