The regulation and organization of two different types of centromeres (mono- and holocentric) were studied in plants. Whereas in the first case a distinct size-restricted centromere distribution is found, the latter one shows an almost chromosome-wide centromere distribution. Despite the strikingly different centromere distribution between mono- and holocentric species, centromeric function is conserved between organisms. Therefore, studies of the organization and regulation of holo- and monocentric chromosomes might provide understanding both conserved and diverged features of centromere biology. The genome organization as well as behaviour of holocentric chromosomes during mitotic and meiotic divisions was studied in the plant species Luzula elegans. The obtained data suggest i) a distinct holocentric chromosome architecture characterized by a longitudinal centromeric groove along each sister chromatid except at chromosome ends, ii) an inverted order of the meiotic chromosome segregation process, i.e. an equational first and a reductional second meiotic division (inverted meiosis), and iii) a different genome organization in comparison to species with monocentric chromosomes. In Arabidopsis thaliana the transcriptional and post-translational regulation of the centromere-specific histone H3 (cenH3) was studied. The data suggest that cenH3, i) is preferentially expressed in dividing tissues, ii) is regulated by E2F transcription factors, which might be conserved between organisms, and iii) is post-translationally phosphorylated by AtAurora kinases in its N-terminal tail.