Karyotype analysis of mitotic chromosomes from crozier tips of Diplazium esculentum (Retz.) Sw.

Cytological research aids in defining species boundaries and resolving taxonomic uncertainty in many taxa. Studies of chromosome numbers and karyotype analysis have improved our understanding of evolutionary processes in plants. Pteridophytes are among the least investigated groups in this field for many reasons, the most notable being the frequent occurrence of genome duplication. In the present study, mitotic chromosomes were used for karyotype analysis. Emerging tips of croziers of Diplazium esculentum at various developmental stages were used to obtain mitotic chromosomes, and the materials were pretreated with paradichlorobenzene, fixed in Carnoy’s fluid, and stained with aceto-orcein for karyotype analysis. The chromosome count from the young crozier tip confirmed the occurrence of 82 chromosomes in its diploid state. The longest chromosome was 3.9159 µm in length, whereas the shortest was 1.6235 µm. Karyotype analysis based on several parameters, together with the predominance of metacentric chromosomes, confirmed the symmetric nature of the karyotype, suggesting that this fern is primitive. In addition to confirming the chromosome number, this study provides karyotype data that distinguish the species and help to clarify its evolutionary relationships.